Published 8-April-2013 by Jenny Hope at dailymail.co.uk
Why a whiff of rosemary DOES help you remember: Sniffing the herb can increase memory by 75%
Useful and attractive: Research has found the essential oil from rosemary helps long-term memory and alertness
• The Tudors believed rosemary had powers to enhance memory
• In Hamlet, Ophelia says ‘There’s rosemary that’s for remembrance’
• Researchers have found the oil helps alertness and arithmetic
Shakespeare was right in saying rosemary can improve your memory.
Researchers have found for the first time that essential oil from the herb when sniffed in advance enables people to remember to do things.
It could help patients take their medication on time, it is claimed, or even help the forgetful to post a birthday card.
In a series of tests rosemary essential oil from the herb increased the chances of remembering to do things in the future, by 60-75 per cent compared with people who had not been exposed to the oil.
Other studies have shown the oil increases alertness and enhances long-term memory.
Rosemary has been long been linked to memory, with the most famous literary reference found in Hamlet when Ophelia declares: ‘There’s rosemary, that’s for remembrance: pray, love, remember.’ It is used in modern-day herbal medicine as a mild painkiller and for migraines and digestive problems.
A team of psychologists at Northumbria University, Newcastle, tested the effects of essential oils from rosemary.
Dr Mark Moss, who will present the findings today at the British Psychology Society conference in Harrogate, said the benefit of aromas was becoming clear through scientific investigation.
He said ‘We wanted to build on our previous research that indicated rosemary aroma improved long-term memory and mental arithmetic.
‘In this study we focused on prospective memory, which involves the ability to remember events that will occur in the future and to remember to complete tasks at particular times. This is critical for everyday functioning, for example when someone needs to remember to post a birthday card or to take medication at a particular time.’
Rosemary essential oil was diffused in to a testing room by placing four drops on an aroma stream fan diffuser and switching this on five minutes before people entered the room.
Altogether 66 people took part in the study and were randomly allocated to either the rosemary-scented room or another room with no scent.
In each room participants completed a test designed to assess their prospective memory functions.
Herb lore: William Shakespeare referred to rosemary's power to enhance the memory in Ophelia¿s line in Hamlet
This included tasks such as hiding objects and asking participants to find them at the end of the test and instructing them to pass a specified object to the researcher at a particular time.
All the tasks had to be done with no prompting but if the task was not performed then different degrees of prompting were used.
The more prompting that was used the lower the score.
The volunteers, all healthy adults, also completed questionnaires assessing their mood.
Blood was taken from volunteers and analysed to see if performance levels and changes in mood following exposure to the rosemary aroma were related to concentrations of a compound known as 1,8-cineole present in the blood.
The compound is also found in the essential oil of rosemary and has previously been shown to act on the biochemical systems that underpin memory.
The results showed that participants in the rosemary-scented room performed better on the prospective memory tasks than the participants in the room with no scent.
This was the case for remembering events, remembering to complete tasks at particular times, and the speed of recall.
The results from the blood analysis found that significantly greater amounts of 1,8-cineole were present in the plasma of those in the rosemary scented room, suggesting that sniffing the aroma led to higher concentrations.
Power of herbs: Rosemary is also used as a painkiller and for migraines and digestion
Previous research suggests volatile molecules from essential oils can be absorbed into the bloodstream through the nose.
The chemicals also stimulate the olfactory nerve in the nose directly, which could have effects on brain functioning.
Researcher Jemma McCready said ‘The difference between the two groups was 60-75 per cent, for example one group would remember to do seven things compared with four tasks completed by those who did not smell the oil, and they were quicker.
‘We deliberately set them a lot of tasks, so it’s possible that people who multi-task could function better after sniffing rosemary oil.’ Miss McCready said ‘There was no link between the participants’ mood and memory. This suggests performance is not influenced as a consequence of changes in alertness or arousal.
‘These findings may have implications for treating individuals with memory impairments.
‘It supports our previous research indicating that the aroma of rosemary essential oil can enhance cognitive functioning in healthy adults, here extending to the ability to remember events and to complete tasks in the future.
‘Remembering when and where to go and for what reasons underpins everything we do, and we all suffer minor failings that can be frustrating and sometimes dangerous. ‘Further research is needed to investigate if this treatment is useful for older adults who have experienced memory decline’ she added.
Florian Birkmayer, M.D., founded the Birkmayer Institute in 2009 to offer holistic person-centered psychiatry and addiction medicine as well as seminars and workshops on a wide range of holistic topics to facilitate self-transformation and continued self-development. This approach has been inspired by C.G. Jung’s ideas about Individuation, which is the journey of the limited ego to the Higher Self. His emphasis in holistic psychiatry is on Equine-assisted therapy, person-centered psychotherapy and holistic medication management including aromatherapy.
I met Dr. Birkmayer in February 2013, when he attended a weekend seminar I gave at the College of Botanical Healing Arts in Santa Cruz. The Birkmayer Institute is located in Albuquerque, New Mexico.
Robert: Not many psychiatrists use essential oils in their practice, in fact I can’t think of any others. What have been your main reference points for how to proceed using essential oils?
Dr. Birkmayer: You are correct that not many psychiatrists use essential oils and I feel like any pioneer in that I’ve had to proceed carefully. My main reference points for using essential oils have been holistic providers, many of whom recognize the interactions between emotional and physical symptoms. Also I have learned a lot from my clients, who are really the experts on their own well-being. Essential oils fit nicely into a client-centered and self-empowering approach. Sylla Sheppard-Hanger’s book The Aromatic Mind has been a very useful guide, as well as Salvatore Battaglia’s Complete Guide to Aromatherapy. There are also several books about the safety, including your Essential Oil Safety, that are very valuable. Unlike many psychiatrists, my clients are generally very interested and willing to try essential oils and report benefits and that is what has kept me going.
Are there different rationales for essential oil use in psychiatry?
I see several rationales: First and foremost, many medications and the approach of many psychiatrists is disempowering to clients, and essential oils restore a client’s sense that there’s something they can do, that empowers them to change their emotional state and cope better. Also, many clients that seek me out have experienced serious side effects and limited benefit from their psychiatric medications and are seeking gentler approaches. However I don’t want to ‘throw the baby out with the bath water,’ and for many clients we use a combination of medications and essential oils. I use the oils both to alleviate symptoms and enhance well-being and coping, but also to counteract side effects of medications.
Are you looking for specific effects from specific oils, or is it all basically ‘feel-good’, or do you use fragrance to anchor feelings?
I use essential oils for specific effects, such as enhancing mood or alleviating anxiety or insomnia as well as to counteract certain side effects of medications. What you refer to as ‘feel-good’ I see as the enhanced sense of well-being that clients get from regaining a sense of resilience and improved coping skills with regards to their symptoms and life stressors. This also allows clients to shift from being symptom-focused to being ‘strengths based’ or ‘recovery oriented.’ In many cases, I tell clients to think of an intention or positive thought when they apply the essential oils, so in addition to the specific effects, the oils can thereby anchor feelings and intentions, or, more broadly, an enhanced sense of self-efficacy.
What type of complaints do you see most?
The most common complaints I see are related to traumic experiences, as well as anxiety, depression, insomnia and side-effects from medications.
Do you mostly use single oils or blends? Why?
I use both single oils as well as blends of up to four or five oils. In my psychiatric practice I’ve met many clients that are on multiple medications, which increases the chance of drug interactions and side effects and one of my core approaches is to simplify medication regimens as much as possible. Similarly when I use oils I try to use a minimum number – it’s more elegant and it’s gentler on the client’s brain.
Do you allow some clients to pick their own oil or blend?
Most of the oils and blends I offer are customized for the individual client with input from them. During a visit, I select a few oils that I feel might be helpful and let the clients smell them and choose the oils that agree with them. The olfactory nerves go directly to the limbic system, which is the part of the brain that processes emotions, and thus how a client reacts to a smell to me is an indication of what their limbic system may need at that time.
What do you hope for in terms of the effects of the oils?
There are many specific effects related to sleep, anxiety, mood, but above all I hope to restore a client’s sense of self-efficacy, so they can cope better with their lives and that the oils become ‘tools in their toolbox of coping skills.’
What are some of your favorites, and what do you mostly use them for?
I have many favorites, but recently I’ve been particularly fond of a simple combination of melissa (lemon balm) and palo santo essential oils which I have given several clients with anxiety and trauma-related issues and it appears to allow people to center themselves and let go of feeling overwhelmed.
Can you describe one or two of your cases where essential oils have played a major role in mental health improvement?
I have a simple blend that I call Sleep Oil that I developed and started using for myself and then shared with colleagues and then with clients – insomnia is a very common problem – and the response has been overwhelming. People are always asking me for more Sleep Oil, giving it to relatives and raving about it. One of the cool things about using this is that it’s applied to the skin. Many people are used to having to ingest something, a medication or a supplement, to get help with insomnia, so when they use Sleep Oil, they unlearn that they need to ingest something to sleep and that goes a long way towards restoring a natural sleep pattern.
Another example: As you may know, some psychiatric medications cause sexual side effects, which can be very distressing. I’ve had success with several clients in overcoming these side effects by using ylang-ylang diluted in a carrier oil and topically applied.
So how exactly are your essential oils used – does it always involve topical application? To skin?
I’ve been using topical application, which I tell clients to think of as anointing themselves as well as sprays which I tell clients to consider their ‘signature scent’.
Apart from treating clients, what are some of your other activities?
One of the goals of The Birkmayer Institute is to offer seminars on a wide range of holistic topics, including aromatherapy. I’ve been teaching a monthly seminar on C.G. Jung’s Red Book for the past year, which has been a remarkable journey. Apart from essential oils and Jung, my greatest passion is equine assisted therapy and I have been blessed that my relationship to horses has gotten deeper and more profound through providing equine assisted therapy and experiencing the healing power of horses. Several times a year, I host a retreat for healers called ‘Horses Healing Healers.’
Do you see any signs that conventional medicine is becoming any more open to the use of unconventional therapy, especially essential oils? Could aromatherapy transform psychiatry?
The clients are very eager for new, more gentle and transformative approaches. However, the field of psychiatry acts reserved and skeptical, even more than providers in other medical specialties, at least on the surface. In private I’ve had several colleagues, especially nurses but also a few physicians, express great interest. My dream is to organize a conference on holistic – especially aromatic – psychiatry in the next couple years, as I suspect there’s a lot of hunger for knowledge.
Dr. Birkmayer received his B.A. from Princeton University and his M.D. from the College of Physicians and Surgeons of Columbia University. He completed his psychiatry residency at the University of New Mexico. He has previously served as the director of the Dual Diagnosis Clinic at University of New Mexico Psychiatric Center and as the director of the Substance Use Disorders program at the Veterans Affairs Medical Center in Albuquerque, NM. He was invited to be a full member of the Group for the Advancement of Psychiatry. He has a long-standing commitment to working with the underserved, e.g. working with Na’anizhozhi Center Inc., a Navajo-tradition based detox and rehab center in Gallup, NM and providing tele-psychiatry to underserved areas. He views himself as a bridge-builder between different medical worlds and works closely and respectfully with a wide range of healers.
There has been much social media discussion recently (February 2012) about the wisdom or otherwise of putting essential oils into your eyes to treat eye problems. This arose from two webpages, here and here. One of these, on the Livestrong website, states: “More and more people are choosing to use alternative medicines to treat minor illnesses rather than taking a prescription. Putting essential oils in or near the eyes isn’t something that is widely known about, but there are several that can aid in the treatment of eye problems. Before using essential oils for your eyes, always contact your doctor.
Clary sage is the essential oil that is most widely used to treat vision problems. It is placed in the eye, so advice from an optometrist is important before use. Clary sage is used as a cleanser for the eyes. It can also be used to clear eye sight due to foggy vision or an injury to the eyes. Clary sage can also be used to brighten the eyes and improve vision. Finally, it can have beneficial results for people with eye issues related to aging” (Eliza Martinez).
Damage to the cornea after inadvertent adminstration of Olbas Oil. Courtesy of Nature Publishing Group
This actually dates from May 2010, but judging from the related comments, has only recently been noticed. The statement that “Clary sage is the essential oil that is most widely used to treat vision problems” is not true, since there are no essential oils commonly used to treat vision problems. The only evidence for any essential oil treating any eye problem relates to tea tree oil and eyelash mites (see below). The reference to clary sage probably derives from 17th century European herbalists, but this refers to using clary sage seeds, or mucilage made from them, and not to clary sage essential oil: “The seed put into the eyes clears them from motes and such like things gotten within the lids to offend them, and it also clears them from any white and red spots which may be on them” (Culpeper 1652). Another common name for clary sage (Salvia sclarea) was “clear eye” because of this common use of the seeds, which probably pre-dated Culpeper by many years. “Clary” may derive from “clear-eye.”
Not only is there no evidence that any essential oil can help with vision problems, age-related or otherwise, but placing any essential oil “in the eye” is extremely dangerous advice. Almost any undiluted essential oil coming into contact with the ocular membranes will be corrosive, possibly causing scarring of the cornea, and certainly causing significant pain.
I could find no reports in the literature of ocular accidents involving single essential oils, but there are several for Olbas oil. This is a mixture of essential oils and menthol:
35.45% Eucalyptus oil
35.45% Dementholized mint oil
18.5% Cajuput oil
3.7% Wintergreen oil
2.7% Juniper berry oil
0.1% Clove oil
A 2009 report from an ophthalmologist in Bristol UK, describes partial loss of corneal tissue (ie erosion) when a 73-year-old man dripped Olbas Oil into his left eye (he had no right eye) because he thought he was using eye drops (see picture above). He was “considerably incapacitated”, but recovered after a week of treatment with “topical antibiotics and lubricants”. On checking, the author found that just his hospital, in the previous 18 months, had seen 12 patients who had mistakenly dripped Olbas Oil into one eye. He describes the result as a chemical burn, though he found that Olbas Oil in tears was pH neutral (most chemical burns are caused by substances that are strongly acid or alkaline). All “Olbas Oil patients” recovered fully within one week following intensive treatment (Adams et al 2009).
Olbas Oil may cause problems even when not applied directly to the eyes. The mother of a 4-month-old boy placed several drops of Olbas Oil in his right nostril in an attempt to help his respiratory infection, not realizing that the product warns against use in infants. The child immediately showed signs of respiratory distress, and was taken to the emergency room. Two hours after admission his eyes became inflamed, and examination revealed bilateral superficial corneal scarring. He also had conjunctivitis, and could not open his eyes. They were flushed with saline over four days, and he recovered with no residual scarring (Wyllie and Alexander 1994).
More than 65,000 work-related eye injuries and illnesses are reported annually in the USA, a “significant percentage” of these being ocular chemical burns. They require rapid treatment, and severe burns have a poor prognosis. The standard treatment is copious irrigation with saline solution for 1-2 hours. Contact lenses should not be removed initially (Peate 2007). With essential oils, fatty oil has been suggested as an appropriate first aid treatment though the advantage of saline is that the eyes can be continually flushed, and this is less easy with fatty oil.
What about diluted essential oils?
The second article describes using essential oils diluted to (by my estimation) about 3%. It includes the following advice:
“Here is a truly natural solution, which has been shown to benefit your eye health and the only one I will use. Gary Young has used this recipe for his patients at the Ecuador Clinic for macular degeneration, health issues, cataracts, and improving sight. I’ve been using it for a couple of years and love it! I started using this recipe before I had to have a vision exam in order to purchase new contacts. And I knew my vision had deteriorated from my last exam. So I put the drops in my eyes every night for about 6 months prior to the exam and my prescription had not changed according to their records, but I know what I was not seeing and I know what I was seeing as a result of using these drops – clearly my vision had improved! The recipe is as follows:
7-10 drops of Frankincense
7-10 drops of Rosemary
7-10 drops of Cypress
2 Tbsp of V-6
Put oils in a glass dropper bottle with a lid on it. My experience has been that I can see much more clearly just after putting the drops in my eye so I am also going to experiment with putting a drop in my eyes in the morning” (Diana Ewald).
“V-6” is a proprietary blend of vegetable oils. The above implies that using these oils on a daily basis is likely to have a healing effect in cases of cataract, macular degeneration or failing eyesight. Although the article continues to describe various effects of the essential oils, none of them have any relationship with any of these conditions. So the question arises – how to weigh potential benefits against potential risks?
The word “experiment” in the above seems appropriate. Eyesight problems are difficult to treat, and once damage has occurred, recovery is not always simple. A 3% dilution may not be sufficient to cause corneal erosion, but on the other hand there is no evidence of any benefit. One concern is that the wrong dilution may be used, and the risk of this is substantial. For example, it would be easy to confuse “tbsp” with tsp”, resulting in a dilution of about 10% instead of 3%.
In a Chinese study, an ointment containing 5% tea tree oil was used by patients whose eyelash follicles were infested with “eyelash mites” (Demodex folliculorum). The ointment was applied to the lid margins with eyes closed, daily for 4 weeks after washing the face, and resulted in considerably less itching and fewer mites. Two of the 24 patients experienced slight irritation from the ointment. The 5% concentration was arrived at after preliminary testing using various dilutions on rabbit eyes (Gao et al 2012).
* Undiluted essential oils should not be applied to the eyes.
* It is rash to suggest that essential oils are commonly used to treat eye problems
* Eye injuries and diseases are medical conditions, and any product claiming to treat them is a medicine, subject to drug legislation.
* There is currently no evidence that applying dilutions of essential oil to the eyes will be beneficial in any condition.
* Diluted (5%) tea tree oil may help eradicate eyelash mites, but it should not be placed into the eyes.
Adams MK, Sparrow JM, Jim S et al 2009 Inadvertent administration of Olbas oil into the eye: a surprisingly frequent presentation. Eye (London) 23:244
Culpeper N 1652 The English Physitian, or an Astro-physical discourse of the vulgar herbs of this nation. Being a compleat method of physick, whereby a man may preserve his body in health; or cure himself, being sick. Thomas Kelly, London
Gao YY, Xu DL, Huang IJ et al 2012 Treatment of ocular itching associated with ocular demodicosis by 5% tea tree oil ointment. Cornea 31:14-17
Peate WF 2007 Work-related eye injuries and illnesses. American Family Physician 75:1017-1022
Wyllie JP, Alexander FW 1994 Nasal instillation of ‘Olbas Oil’ in an infant. Archives of Disease in Childhood 70:357-358
This article also appears in the International Journal of Professional Holistic Aromatherapy, Vol. 1 Issue 4
I would really appreciate it if you could tell me what type of vitamin E to use to slow the oxidation of essential oils, as in cream. Is it just tocopherol? Or some other type?
Thank you for your time.
PS. I enjoyed your webinar very much!
There are four principal isomers (chemical subtypes) of tocopherol:
There are also sub-types of each one.
You can use ‘mixed’ tocopherols: all four in various proportions. But my preference for essential oils is to use alpha-tocopherol, specifically d-alpha tocopherol. Here is a supplier that sells small quantities, as well as large.
Because it is very viscous, you may want to mix it 50/50 with a fatty oil or essential oil before adding to your product. You don’t need much – the tocopherol should be added at 0.1% by weight of the total product. Putting more in won’t be more effective.
Although ‘tocopherol’ and ‘vitamin E’ are often used synonymously, vitamin E is actually even broader, because the term encompasses both tocopherols and tocotrienols.
Hello there. I am in hopes you can please help me. I currently use the doTERRA line of essential oils and I also have used them to help my 18month old daughter. I have recently used ylang-ylang, roman chamomile, lavender and sandalwood to reduce stress and attempt to balance my hormones that have been out of wack since my pregnancy. Unfortunately, my husband is extremely skeptical as to the healing properties of EO’s as well as the safety of their use. He is concerned about the oils coming through my breast milk and causing issues for our daughter and recently he attributes my use of Lavender and Roman Chamomile on our daughter’s severe diaper rash as exacerbating the rash. I tried to explain that her reaction to anything on her rash when it was this raw would have made her scream and cry, but unfortunately, he attributes it only to my use of the oils. I also tried to explain the healing properties of those two oils specifically for diaper rash, but he says that he saw me “burn her” with the 2 oils based on her screaming response to the diaper change.
Would you mind please responding by addressing my husband’s concerns as well as pointing him in a direction where he can read scientific evidence of the healing properties and explain the safety of the use of oils with regard to our baby, pregnancy and breast feeding? Are there any specific oils not to use during pregnancy or breast feeding? And lastly, do you have an opinion on the doTERRA brand of oils and that they claim to be Certified Pure Therapeutic Grade?
Thank you so much for helping to educate my husband, so that I may continue to help my family in a natural, alternative way. I am not a fan of antibiotics (unless absolutely necessary) or synthetic and chemical treatments or remedies. I am very concerned with a lot of these questionable ingredients in our western over the counter and prescribed medicines.
As far as the oils I listed as having used on myself, I use 1 neat drop rubbed on the back of my neck or collar bone or wrist once to twice a day. The lavender & Roman Chamomile used on my daughter has been applied 2 drops of each in my hands patted on her dry, clean bottom. This is how I did it 2 days ago and she did not get upset and it seemed to help alleviate her itching, but since then, her rash has gotten worse from more acidic urine and feces and the rash now appears more raw and is weeping. Today, I did the same type of application & then let her be without a diaper for an hour while she laid on top of me & rested, and the redness has already subsided substantially. There is still the raw spot though.
The information I seek as being most important is in regards to the possibility of exacerbation of the rash by use of the oils, the possibility of oils harming our daughter through topical and/or aromatic applications to our daughter, the possibility of oils harming our daughter by way of my breast milk, if there are specific oils not to use while pregnant and or breastfeeding and any scientific studies and/or evidence showing the healing properties of the oils that my husband can reference.
Also, if you wouldn’t mind touching on your opinion of doTERRA’S line and in your professional opinion sharing with me if you think it is a credible product.
Once again, thank you very much for trying to answer my questions! I truly appreciate your efforts!
Thank you and in health,
In my opinion, your use of 1 or 2 drops a day on yourself will have no effect in regard to breastfeeding. Of that amount, at least 95% evaporates or rubs off on clothes, and only a very small percentage of what you do absorb will reach breast milk (or fetus). You would probably absorb just as much essential oil from eating a couple of oranges or a bowl of strawberries.
Most essential oils, including lavender & Roman chamomile, have a drying effect if used undiluted on the skin, for the same reason that alcohol is drying – rapid evaporation. It does not sound as if your use of these oils has made things worse, but I would caution you against using the oils in this way because it does increase the risk of irritation or allergic reaction, especially for a baby, which has relatively thin skin.
Do use the oils, but mix into a vegetable oil, gel or cream base before use, for a baby at no more than 1%, or one part in 100. Barrier creams for babies are made to form a literal barrier over the skin, to protect it from the urine, feces etc. Essential oils, if anything, have the opposite effect – helping other substances to penetrate the dermal layers.
In my opinion, DoTerra essential oils are good quality though over-priced. I have written about ‘therapeutic grade’ claims here. I don’t have an easy-to-reference list of oils to avoid in pregnancy, but the most important would be fennel and anise. Here is a link to research on lavender oil.
I hope this is helpful.
Lavender oil does not mimic estrogen nor does it enhance the body’s own estrogens. It is therefore not a ‘hormone disruptor’, cannot cause breast growth in young boys (or girls of any age), and is safe to use by anyone at risk for estrogen-dependent cancer. The lack of estrogenic action is the conclusion of a new report, which used a novel form of ‘uterotrophic’ assay.
This measures the effect of a test substance on the uterus of immature or estrogen-deprived female rats over three days. Any estrogenic action causes a rapid and measurable increase in uterine weight. The assay has been in use since the 1930s, was adopted by the OECD in 2007, and is now regarded as the “benchmark animal assay for estrogenic effects” (Politano 2013).
A 2007 report by Henley et al found that both lavender and tea tree oils had a weak in vitro estrogenic action. Lavender was suggested as the cause of three cases of prepubertal gynecomastia (breast growth) in boys, and tea tree was suggested in one case. The report was subsequently criticized on a number of grounds. For example it was pointed out that there was no evidence of either essential oil causing the gynecomastia in any of the four cases, and that in vitro estrogenic findings frequently do not extrapolate to a similar action in warm bodies (see Rebuttals, below).
Since 2007 there have been many warnings about lavender and tea tree oils that relate back to this study. Others, including myself, have suggested that such cautions are unnecessary and premature. The new research, in which considerable quantities of lavender oil were used, found that there was no increase in uterine weight, and so no estrogenic action.
The novel aspect of the uterotrophic assay was that the test substance – lavender oil – was applied to the skin, while the most common method is subcutaneous injection. This was changed in order to mimic the circumstances of the Henley et al 2007 case reports, and it also mimics the use of lavender oil in fragrances and personal care products. Lavender oil was used in two concentrations, 4% and 20% in corn oil. According to Politano et al 2013, these concentrations are respectively more than 6,000 and 30,000 times greater than a conservative estimate of human skin exposure from multiple cosmetic products containing lavender oil. They are also 5,000 and 1,000,000 times greater than the estimated exposure to lavender oil experienced by the Henley et al boys.
These calculations may seem exaggerated, but the massive differences are because in the uterotrophic assay, the lavender oil was applied in Hilltop Chambers patches, which do not allow any evaporation, or loss of essential oil by means other than dermal absorption. Examples of the quantities of fragrant substance absorbed from personal care products are shown below. The amount of fragrance absorbed from a shampoo, for instance, is 200 times less than the amount applied to the head. If amounts of dermally-absorbed lavender oil that are at least 5,000 times greater than any normal human exposure are not estrogenic, then we can be confident that this particular safety issue is not a concern.
Data from Cadby et al 2002
Safety in pregnancy is a broader question than hormonal action alone, since affects on the fetus, or even miscarriage, are theoretically possible with any substance. The question of uterine stimulation and miscarriage was thoroughly investigated here, and there is clearly no risk. As for fetal effects we know that linalool, a major constituent of lavender oil, is not fetotoxic to pregnant rats at an oral dose 1 g/kg/day for 16 days (equivalent to a human oral dose of 60 g, or 2 oz per day, and a total dose of 32 oz). The chances of lavender oil being fetotoxic in the amounts used in personal care products are negligible, considering the small amounts both applied to, and subsequently absorbed by human skin (Cadby et al 2002).
The new research findings represent a major development in our knowledge of lavender oil safety, since the possibility of estrogenic action now looks remote. While no single test should be taken as absolutely conclusive, we can expect the volume of noise about lavender being estrogenic to diminish considerably.
Dean CJ 2007 Prepubertal gynecomastia linked to lavender and tea tree oils. New England Journal of Medicine 356:2543-2544
Kalyan S 2007 Prepubertal gynecomastia linked to lavender and tea tree oils. New England Journal of Medicine 356:2542-2544
Kemper KJ, Romm AJ, Gardiner P 2007 Prepubertal gynecomastia linked to lavender and tea tree oils. New England Journal of Medicine 356:2541-2542
Kurtz JL 2007 Prepubertal gynecomastia linked to lavender and tea tree oils. New England Journal of Medicine 356:2542-2543
Lawrence BM 2007 Estrogenic activity in lavender and tea tree oils: Part I. Perfumer & Flavorist 32:20-25
Lawrence BM 2007 Estrogenic activity in lavender and tea tree oils: Part II. Perfumer Flavorist 32:14-20
Tisserand R Tea tree and lavender not linked to gynecomastia
Cadby P A, Troy W R, Vey M G 2002 Consumer exposure to fragrance ingredients: providing estimates for safety evaluation. Regulatory Toxicology & Pharmacology 36: 246-252
Henley DV, Lipson N, Korach KS, Bloch CA 2007 Prebubertal gynecomastia linked to lavender and tea tree oils. New England Journal of Medicine 365(5): 479-485
Politano VT, Lewis EM, Hoberman AM et al 2008 Evaluation of the developmental toxicity of linalool in rats. International Journal of Toxicology 27:183-188
Politano VT, McGinty D, Lewis EM et al 2013 Uterotrophic assay of percutaneous lavender oil in immature female rats. International Journal of Toxicology Open access article
I have read that the essential oil extraction process can (but doesn’t’ always) include the use of solvents, and that many of the manufacturers buy and distribute oils that contain these solvents (claiming that they are pure). Can you recommend a manufacturer and or a distributor that can be trusted to sell high quality oils?
Dr. James Lembeck
Essential oils are extracted by steam or water distillation, citrus oils generally by expression. Other than water or steam, no solvents are involved. So there are no solvent-extracted essential oils.
Concretes, absolutes and resinoids are extracted using solvents, most commonly hexane. (Benzene used to be used, but is no longer due to toxicity). This is the nature of the process, so there are no concretes or absolutes that are not extracted using solvents. Absolutes are widely used in fragrances and food flavorings, and a few are used in aromatherapy – most commonly rose and jasmine. Rose essential oil is also produced. So there are rose oils, and also rose absolutes.
Concretes and absolutes always contain traces of the solvent used – usually in the 1-5 ppm range. Hexane is not highly toxic, and this concentration of hexane possesses zero toxicity, hence approval for food use.
CO2 extracts are made using CO2 as a solvent. Of course we are constantly exposed to large concentrations of CO2 whenever we breathe, so it is not toxic to humans. CO2 extracts are neither essential oils nor absolutes.
Very occasionally, extraction is performed using both distillation and solvent extraction, but this is almost never used for commercial production – only experimental.
If you want to avoid fragrance raw materials that contain solvents, then don’t buy concretes or absolutes.
My husband has just been diagnosed with endocarditis. His doctor wants to start him on intravenous antibiotics followed by oral doses of antibiotics. I was hoping to support him with essential oils. Do you think that’s safe, or could they interfere with the effectiveness of the antibiotics?
I would appreciate your advice.
In this situation you can do no harm with essential oils. They often help considerably, as many essential oil/antibiotic combinations are more effective than the antibiotic treatment alone. And if they don’t help at all, you have lost nothing. There is no such thing as eradicating an infection too efficiently. Just don’t stop the antibiotics too soon.
One of the outstanding properties of many essential oils, including tea tree (Melaleuca alternifolia), is that they can be effective even against bacterial biofilms.
A biofilm is a layered matrix, consisting mainly of polysaccharide and protein, that bacteria or fungi create on a surface as a secure habitat. In this form they are more difficult to kill, because the biofilm structure affords protection from the environment. Plaque on teeth is an example of a biofilm and the success of ‘essential oil’ mouthwashes such as Listerine compared to others is partly due to their ability to break down and inhibit plaque formation (Oyanagi et al 2012). (Listerine contains four essential oil constituents: thymol, menthol, 1,8-cineole and methyl salicylate. It was originally developed and used as a surgical antiseptic.)
In a biofilm, the outer layer consists of more or less dormant cells that are also especially resistant. Medical implants, such as heart valves, catheters, stents etc, are becoming more common. They are subject to colonization by bacterial biofilms, and if this occurs the result can be fatal, as antibiotics have great difficulty penetrating the outer layer of resistant bacteria (Hoiby et al 2010). Consequently, implant-related fatalities are on the rise.
Staphylococcus aureus biofilm on a catheter
Carvacrol and cinnamaldehyde (major constituents of oregano oil and cinnamon bark oil respectively) inhibited biofilm formation on a polymer coating. It is proposed that medical devices coated with such compounds would be much less susceptible to bacterial colonization. Cinnamaldehyde significantly reduced Pseudomonas aeruginosa biofilm at 1%, and most bacteria were inhibited by either compound at 0.1% (Zodrow et al 2012). P. aeruginosa is one of the most difficult bacteria to kill. It forms mucosal biofilms in the lungs in cystic fibrosis, and it can be a problem in wound healing.
Biofilm may be found on contact lenses, chronic wounds and ulcers, vaginal mucous membrane, in fact on any surface where there is moisture and nutrients. It is constantly forming on our skin, in addition to the usual mix of dirt, sebum, sweat and cosmetics. Biofilms are also found on surfaces outside the body. Because of a combination of grease-cutting and antibiofilm properties, pine oil and orange oil are common ingredients in household disinfectants. More on biofilms here.
In vitro testing often shows antibiotics to be more effective than essential oils. Conversely, some essential oils are more effective at killing bacteria in biofilm, because they can penetrate it more effectively, and because they are less susceptible to resistant mechanisms. Essential oils that have shown good antibiofilm action in in vitro testing include:
- Cinnamon bark: Staphylococcus epidermis biofilm (Nuryastuti et al 2009)
- Oregano: S. aureus and S. epidermis biofilm (Nostro et al 2007)
- Thyme: Listeria monocytogenes biofilm on stainless steel and polystyrene (Desai et al 2012)
- Rosemary: Candida albicans and C. tropicalis biofilm (Chifiriuc et al 2012)
- Tea tree: S. aureus, MRSA and C.albicans biofilm (Kwiecinski et al 2009, Park et al 2007, Sudjana et al 2012)
Some of these essential oils are now being considered for use in food preservation, another situation where biofilm formation is a challenge.
Melaleuca alternifolia in flower (Australian Tea Tree Industry Association)
Staphylococcus aureus is a ubiquitous bacterium, notably found on the skin. In vitro research shows that tea tree oil dose-dependently eradicates S. aureus biofilm (Kwiecinski et al 2009) and that it is effective against MRSA and MSSA biofilm (Brady et al 2006). A 50% concentration of tea tree oil was as effective as vancomycin in vitro in eradicating MRSA biofilm on typanostomy tubes (Park et al 2007). S. aureus biofilm, in an infected cochlear implant, was found to be resistant to all conventional antimicrobials, but 5% tea tree oil completely eradicated it in one hour (Brady et al 2010). Tea tree oil has shown good effect in eradicating MRSA on the skin, used at 5% in a body wash, in addition to either 4% in an ointment (Caelli et al 2000) or 10% in a cream (Dryden et al 2004).
Candida albicans forms biofilms that cause disease and are difficult to treat with conventional antifungal agents. At 0.031% in vitro, tea tree oil significantly reduced biofilm formation for all of 10 C. albicans isolates tested (Sudjana et al 2012). Further in vitro work suggests that tea tree oil may be effective in oral hygiene products for the prevention and control of oral candidosis in cancer patients (Bagg et al 2006, Ramage et al 2012). In 25 AIDS patients with oral candidosis who had not responded to fluconazole treatment, 7 were cured and 8 improved after four weeks using oral solutions containing tea tree oil (Vazquez et al 2002).
These studies suggest promising uses for essential oils, notably tea tree, in the prevention and eradication of biofilm-related medical problems that may be resistant to conventional treatment, as well as in surface cleaning, hand hygiene and skin cleansing products.
Bagg J, Jackson MS, Sweeney MP et al 2006 Susceptibility to Melaleuca alternifolia (tea tree) oil of yeasts isolated from the mouths of patients with advanced cancer. Oral Oncology 42:487-492
Brady A, Loughlin R, Gilpin D et al 2006 In vitro activity of tea-tree oil against clinical skin isolates of meticillin-resistant and -sensitive Staphylococcus aureus and coagulase-negative staphylococci growing planktonically and as biofilms. Journal of Medical Microbiology 55:1375-1380
Brady AJ, Farnan TB, Toner JG et al 2010 Treatment of a cochlear implant biofilm infection: a potential role for alternative antimicrobial agents. Journal of Laryngology, Rhinology & Otology 124:729-738
Caelli M, Porteous J, Carson CF et al 2000 Tea tree oil as an alternative topical decolonization agent for methicillin-resistant Staphylococcus aureus. Journal of Hospital Infection 46:236-237
Chifiriuc C, Grumezescu V, Grumezescu AM et al 2012 Hybrid magnetite nanoparticles/Rosmarinus officinalis essential oil nanobiosystem with antibiofilm activity. Nanoscale Research Letters 7:209
Desai MA, Soni KA, Nannapaneni R et al 2012 Reduction of Listeria monocytogenes biofilms on stainless steel and polystyrene surfaces by essential oils. Journal of Food Protection 75:1332-1337
Dryden MS, Dailly S, Crouch M 2004 A randomized, controlled trial of tea tree topical preparations versus a standard topical regimen for the clearance of MRSA colonization. Journal of Hospital Infection 56:283-286
Hoiby N, Bjarnsholt T, Givskov M et al 2010 Antibiotic resistance of bacterial biofilms. International Journal of Antimicrobial Agents 35:322-332
Kwiecinski J, Eick S, Wojcik K 2009 Effects of tea tree (Melaleuca alternifolia) oil on Staphylococcus aureus in biofilms and stationary growth phase. International Journal of Antimicrobial Agents 33:343-347
Nostro A, Sudano Roccaro A et al 2007 Effects of oregano, carvacrol and thymol on Staphylococcus aureus and Staphylococcus epidermidis biofilms. Journal of Medical Microbiology 56:519-523
Nuryastuti T, van der Mei HC et al 2009 Effect of cinnamon oil on icaA expression and biofilm formation by Staphylococcus epidermidis. Applied & Environmental Microbiology 75:6850-6855
Oyanagi T, Tagami J, Matin K et al 2012 Potentials of mouthwashes in disinfecting cariogenic bacteria and biofilms leading to inhibition of caries. The Open Dentistry Journal 6:23-30
Park H, Jang CH, Cho YB et al 2007Antibacterial effect of tea-tree oil on methicillin-resistant Staphylococcus aureus biofilm formation of the tympanostomy tube: an in vitro study. In Vivo 21:1027-1030
Ramage G, Milligan S, Lappin DF et al 2012 Antifungal, cytotoxic, and immunomodulatory properties of tea tree oil and its derivative components: potential role in management of oral candidosis in cancer patients. Frontiers in Microbiology 3:220
Sudjana AN, Carson CF, Carson KC et al 2012 Candida albicans adhesion to human epithelial cells and polystyrene and formation of biofilm is reduced by sub-inhibitory Melaleuca alternifolia (tea tree) essential oil. Medical Mycology 50:863-870
Vazquez JA, Zawawi AA 2002 Efficacy of alcohol-based and alcohol-free melaleuca oral solution for the treatment of fluconazole-refractory oropharyngeal candidiasis in patients with AIDS. HIV Clinical Trials 3:379-385
Zodrow KR, Schiffman JD, Elimelech M 2012 Biodegradable polymer (PLGA) coatings featuring cinnamaldehyde and carvacrol mitigate biofilm formation. Langmuir 28:13993-13999
At almost 850 pages, there’s plenty of reading here. Unfortunately, this book is replete with errors. There are innumerable mis-spellings of the names of chemicals. Terpinen-4-ol is an alcohol, not a phenol, and bergamotene is a terpene, not a furanocoumarin. On page 374 we read that “Coumarins are thought to be antispasmodic, as are many other esters.” Coumarin is not an ester. Stewart mentions that myrrh oil is rich in ‘furanoid compounds’ – well yes, it is indeed rich in FURANS, and he goes on to say that “furanoid compounds can amplify ultraviolet light and can make an oil phototoxic.” (p23/24). Well, I don’t know why he wants myrrh oil to be phototoxic, but it isn’t, because it contains no FURANOCOUMARINS. Using the term ‘furanoid compounds’ fails to make a vital distinction – between (phototoxic) furanocoumarins, and (non-phototoxic) furans.
In some cases Stewart seems to have copied mistakes from other sources, without realizing they were mistakes. l-Limonene is quite often given instead of d-limonene, and methyleugenol has curiously disappeared as an essential oil constituent altogether – Stewart does not list it a constituent of any of the oils it is actually found in! Furanocoumarins are frequently cited that may indeed be present in the plant but are not found in the essential oil.
He has made a valiant effort to list the components of 113 essential oils, but the method he used – combining data from various books – is risky. The end result is said to represent a ‘typical’ essential oil, but is rather hit-and-miss, and in many cases does not represent any existing essential oil at all. Some of the total percentages add up to more than 100%. Reporting constituent chemistry from different sources is a challenge I am often confronted with myself, but there are more elegant solutions.
Stewart is highly critical of what he calls the ‘British School’ of aromatherapy, because it espouses the idea that some essential oils can be dangerous, and because, according to Stewart, it “relies on scientific research on animals”. However, he does take on board the idea that some furanocoumarins are phototoxic. Stewart perhaps does not realize that phototoxicity in essential oils is almost entirely based on RIFM research using pigs, and much of the ‘French’ information about essential oil constituents that Stewart cites is based on animal research. If the book was properly referenced, this would be obvious. He also criticizes the British for “usually applying only certain compounds isolated from essential oils rather than the whole oil.” (p4) It is difficult to fathom from where he plucked this outrageous notion!
There is a massive amount of information here, but there is not a single scientific reference to back up any of it. The result is an uncomfortable mix of fact and fiction. The book perpetuates the myth that any dangers of essential oils (apart from phototoxicity) only apply to what he calls ‘perfume grade’ oils, which, according to Stewart, British aromatherapists like to use! I’m not sure then, who buys all the independently certified organic essential oils sold in Britain. There is no ‘perfume grade’ of essential oil (on either side of the Atlantic), nor is there a ‘therapeutic grade‘. [The grades that do exist are various organic certifications, ISO standards, BP (British Pharmacopeia) standards, and FCC (Food Chemicals Codex) standards.]
Stewart does humanity and science a disservice by alleging that it is impossible for an essential oil to cause an allergic reaction: “Occasionally, a person receiving essential oils claims to have had allergic reaction to them….such a reaction is never allergenic…they are usually therapeutic and indicate the initiation of a cleansing, healing process.” (p451) Stewart goes on to explain his hypothesis that essential oil constituents cannot be allergenic, because they are not composed of amino acids. No, they are not composed of amino acids, but yes, they can in fact cause allergic reactions, because an essential oil constituent such as cinnamaldehyde (known as a ‘hapten‘) can combine with proteins in the skin and can then be recognized by the immune system as an allergen. This is not new science, and Stewart’s bending of the facts to suit his world view is shameful and potentially dangerous.
There is a lot of information in this book and it is by no means all wrong, but the fact-to-error ratio is too rich for me, and the way he plays with words to make ‘his truth’ look like fact is disturbing. On page 462 he states: “There has never been a documented instance of antigen-antibody response (i.e. sensitization) to an essential oil. Essential oil antibodies have never been found or detected in anyone. Never.” The last part is true, but only because (a) you can’t have an antibody to an essential oil, only an essential oil constituent (is this genuine ignorance of basic biology, or just more fact-bending?), and (b) no scientist has ever found antibodies to essential oil constituents, because no scientist has ever looked for them. Perhaps the clinical reality of an allergic reaction needs no proof. Here are two documented cases of allergic reaction to cinnamon bark oil:
Ackermann L, Aalto-Korte K, Jolanki R et al 2009 Occupational allergic contact dermatitis from cinnamon including one case from airborne exposure. Contact Dermatitis 60:96-99
Sánchez-Pérez J, García-Díez A 1999 Occupational allergic contact dermatitis from eugenol, oil of cinnamon and oil of cloves in a physiotherapist. Contact Dermatitis 41:346-347
The IFRA safety standards require that cinnamon bark oil should not be used on the skin at more than 0.6%, to avoid allergic reactions.
Essential Oil Safety – a rebuttal
Stewart is critical of my book, Essential Oil Safety. Here are some of his comments:
Much of the research cited is on the toxic effects of single components of an oil, which is an invalid application of science. This is an incredible statement, considering that most of Stewart’s book is devoted to explaining essential oil chemistry, and the relationships between constituents and therapeutic properties. On page 468, for instance, Stewart says: “essential oils rich in phenols should be used with caution when applying to the skin.” If extrapolating single component data to whole essential oils is not OK when I do it, why is it OK when Stewart does it?
Furthermore, as the authors point out, in all of the studies they cite, the data are for animals (not people) and/or the tests were not for the whole oil but for isolated compounds of an oil. These types of studies are not valid indicators of the behavior of oils in actual practice. (p21/22) This is simply not true, and is not stated anywhere in the Essential Oil Safety text. There are many studies cited in Essential Oil Safety where whole essential oils were patch-tested on individuals (such as the two reports for cinnamon above), and there are many cited cases of poisoning from whole essential oils. And, see my previous comment.
There are two places where I have been mis-quoted:
1) In the preface the authors state “this text was largely an extrapolation of toxicological reports from the Research Institute for Fragrance Materials (RIFM).” In other words, this book is based on data that apply only to perfume grade oils which are customarily refined, denatured, and laced with synthetics. (p787)
This is what the preface actually says:
“This book [i.e. Essential Oil Safety] replaces The Essential Oil Safety Data Manual by Robert Tisserand, first published in 1985. This text was largely an extrapolation of toxicological reports from the Research Institute for Fragrance Materials (RIFM).” So , I was not referring to Essential Oil Safety at all, I was referring to a previous, and very much smaller book.
2) These authors state on p ix, “the majority of essential oils we recommend should not be available to the general public”. In their opinion, the majority of essential oils should be restricted only to what they would regard as “qualified aromatherapists.” (p788)
This is what is actually said:
“In the UK and USA at least, it is currently possible to purchase, by mail order, the majority of the essential oils which we recommend should not be available to the general public.” Stewart is trying to make it sound as if I don’t believe essential oils should be available to the general public. Of the 450 odd essential oils produced today, I do believe that a dozen or so should not be publicly sold, because they are so toxic. To suggest that I am not in favor of ordinary people having access to essential oils is just incredible. David Stewart, what do you think I have been doing for the past 40 years? Why is there a brand of essential oils called Tisserand Aromatherapy? Why are these essential oils available to anyone? Why did I write The Art of Aromatherapy in 1977? And what was I thinking when I wrote a book called Aromatherapy for Everyone in 1988?
In both cases, by omitting the first part of the sentence, the meaning has been completely changed. And in the second quote, two words were omitted to further change the meaning. It’s sad that someone should invest so much energy in writing a comprehensive text, and then sabotage it by trying to bend the truth to suit a commercial agenda. (And if there is no commercial agenda, why are Young Living products mentioned throughout the book?)