Marianne asks:
A perennial question – if essential oils are diffused in a room and someone lights a candle or a cigarette, is this a fire risk? If not, why not? At a famous Oncology hospital in the U.K. essential oil diffusers are not used for this reason – in case a spark from any electrical equipment (including pulling out a plug from the wall) gets in touch with any diffused oil! But you could say the same, if essential oils are used for massage, creams and compresses, the scent is in the air which means that volatile molecules are in the air.
Have a great day. Marianne
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Vaporized essential oil in the air is not a fire risk. If it was, I imagine a lot of houses would have burned at this point. Maybe if you somehow managed to vaporize a few kilos of essential oil in a small room, and then lit a flame…? It would be hard to breathe though – you might suffocate before you got your flame going.
Where there have been problems is with burner/vaporizers that use a naked flame candle – these have been known to “spontaneously” catch fire, and they are a fire hazard. When a naked flame comes into direct contact with concentrated essential oils and a very hot burner, sometimes with oily residues, this can be a risk. Much better to use ones that operate without a naked flame.
As for a spark from electrical equipment, this has never been known to ignite essential oil, and I can’t imagine a scenario where it would be a problem. How far do those sparks shoot? 2 inches? But, with UK health & safety, every theoretical risk is assumed to be potentially fatal these days!
Dit artikel is ook beschikbaar in het Nederlands!
A question came up recently on TheBeautyBrains forum: Lavender oil in cosmetics – does it cause skin cell death, and is that a problem? This was in response to the description of “lavender extract and oil” on Paula Begoun’s Cosmetic Ingredient Dictionary. Paula is known for her belief that fragrances, natural or synthetic, have no place in cosmetic products. Here are some random examples from her website: “Cedarwood oil: there is evidence that cedarwood oil is allergenic and can cause skin irritation. Rose oil: Fragrant, volatile oil that can be a skin irritant and sensitizer. Tangerine oil: Fragrant, volatile citrus oil that can be a skin irritant.” And so on. In her profile of lavender oil, she goes out of her way to find negative information, but is hard pressed to find anything positive to say:
Lavender: widely-used plant that’s a member of the mint family. It is primarily a fragrance ingredient, although it may have antibacterial properties. There is no research showing it has any benefit for skin (Sources: Phytotherapy Research, June 2002, pages 301–308). In fact, it can be a skin irritant but there is a conflicting research on just how much of a photosensitizer lavender can be. It appears lavender oil all by itself isn’t a photosensitizer, but when exposed to oxygen (as it would be when applied to your skin), one of it’s fragrant components, linalyl acetate forms substances that lead to allergic contact dermatitis in and out of sunlight (Sources: The New Ideal in Skin Health: Separating Fact from Fiction, Thornfeldt, Carl M.D., Allured Books, 2010, pages 286–287; Contact Dermatitis, January 2008, pages 9–14; Hautarzt, February 2002, pages 93–97; and Contact Dermatitis, August 1999, page 111).
Research also indicates that other components of lavender, specifically linalool, can be cytotoxic, meaning that topical application causes skin-cell death (Source: Cell Proliferation, June 2004, pages 221–229). Lavender leaves contain camphor, which is known as a skin irritant. Because the fragrance constituents in lavender oil oxidize when exposed to air, lavender oil is pro-oxidant. This enhanced oxidation also increases its irritancy on skin (Source: Contact Dermatitis, September 2008, pages 143–150). Lavender oil is the most potent form, and even small amounts of it (0.25% or less) can be problematic. It is a must to avoid in skin-care products, but is fine used as an aromatherapy agent for inhalation or relaxation (Source: Psychiatry Research, February 2007, pages 89–96; and www.naturaldatabase.com).
Let’s take a look at these points one at a time.
“There is no research showing it has any benefit for skin”
Well, this was almost true in 2002, but not quite. Of the articles I’m about to cite, all except three were published either in 2002, or later. But today, this statement makes no sense. One of the early papers was on wound healing (Guba 1998/1999). A mixture of oils including 4% lavender oil was used on 18 patients with skin ulcers or wounds. In most cases the formulation was applied daily, and healing took from 5 days to 12 weeks. There were no adverse reactions. In an anti-allergic study, lavender oil, applied to the skin of rats or mice at 0.1%, 1.0%, 10% or 100%, inhibited immediate-type allergic reactions. It also inhibited the release of the inflammatory mediators, TNF and histamine (Kim & Cho 1999). In a clinical trial of 120 women post-childbirth, lavender oil sitz baths (a few drops in water) significantly reduced redness during healing after episiotomy (Vakilian et al 2011). Two other studies have reported positive effects for lavender oil in wound healing (Hartman & Coetzee 2002, Kerr 2002). No adverse reactions were reported in any of the above studies. Hartman & Coetzee also used lavender oil at 4%, and blue chamomile oil at 2%.
From Hartman & Coetzee (2002)
Lavender is one of the most active essential oils against MRSA (Edwards-Jones et al 2004), and the benefits of preventing MRSA establishing itself on your skin should not be underestimated. Lavender oil is moderately active against Propionibacterium acnes (Zu et al 2010), one the the principal bacteria involved in acne. It is moderately active against two of the principal fungi that can cause skin problems such as athlete’s foot and ringworm (Trycophyton rubrum and T. mentagrophytes) (Cassella et al 2002), and highly active against a third, Candida albicans (D’Auria et al 2005). The use of up to 0.5% of lavender oil in aqueous body milks allowed the regular synthetic preservative to be cut back by up to 8.5 times without any reduction in efficacy (Kunicka-Styczynska et al 2009). Lavender oil is very effective against some problematic bacteria and fungi found on the skin, but not all (Kunicka-Styczynska et al 2011, Sokovic et al 2010) so it would not be appropriate to use as a stand-alone preservative.
There is anecdotal evidence that lavender oil is a useful remedy for burns (Gattefossé 1993, p87). This is supported by the antimicrobial data above (i.e. preventing infection), and by the fact that lavender oil has a proven analgesic action (Ghelardini et al 1999, Sakurada et al 2009). This action is mostly due to linalool, and may also explain why lavender oil reputedly soothes bee stings, something I can personally attest to. Burns too.
Ultra-violet (UV) radiation can damage the skin because it leads to the generation of free radicals. The body has a limited amount of protective antioxidant enzymes, and these enzymes tend to decrease with age, making the skin more vulnerable to oxidative stress. A Japanese study reported that lavender oil inhibited the generation of singlet oxygen, which causes the most damage in response to UVA/UVB radiation (Sakurai et al 2005). This suggests that the regular use of lavender oil in skin preparations could suppress the aging effects of sunlight on the skin. Lavender oil has shown excellent antioxidant activity in several assays (Yang et al 2010), suggesting that it could inhibit degenerative change such as skin cancer, sun damage and the effects of ageing. Linalool, one of the major constituents of lavender oil, has shown very good in vitro activity against human basal cell carcinoma (Cherng et al 2007) and a topically applied 10% dilution of linalool reduced skin tumor incidence in mice by 33% (Gould et al 1987).
So today we can say that the principal known benefits of using lavender oil on the skin are that of numbing pain and healing wounds (cuts, sores, abrasions, ulcers), and other probable benefits include preventing bacterial colonization, treating fungal infections, combating blemishes, preventing skin cancer, and countering the damaging effects of UV radiation (photo-ageing).
“There is a conflicting research on just how much of a photosensitizer lavender can be.”
There is no conflict. Perhaps Paula Begoun does not know the difference between phototoxicity and photoallergy. She also seems to have confused allergic reaction with phototoxicity. I know, dermatology jargon can be very confusing! Lavender oil is not photosensitizing on the skin (Opdyke 1976 p451), and linalyl acetate is neither a photoirritant nor a photoallergen (Bickers et al 2003). This means that there is no risk of an adverse reaction in strong sunlight, as there is with bergamot and some other citrus oils.
There is one report of photoallergy to lavender oil (Goiriz et al 2007). This is the only case of photoallergy to lavender oil ever reported, and photoallergy from essential oils is so rare that it can be discounted as a risk. This is not only a non-issue, it’s also ironic, considering lavender’s protective action in relation to UV radiation damage.
Photo-ageing
“When exposed to oxygen (as it would be when applied to your skin), one of it’s fragrant components, linalyl acetate forms substances that lead to allergic contact dermatitis in and out of sunlight.”
Lavender oil contains two major constituents in approximately equal amounts – linalool and linalyl acetate. Oxidation is actually more of a problem with linalool than with linalyl acetate, and it’s true that, over a period of months or years, lavender oil constituents can oxidize to hydroperoxides. These “oxidation products” are often slightly more skin-allergenic than the original compounds (which are virtually non-allergenic). However, oxidation is a very slow process – it does not happen in a few minutes while a product is sitting on your skin! To avoid the possibility of oxidation, I recommend that products containing lavender oil also include an added antioxidant. This is in line with the International Fragrance Association recommendation that essential oils high in linalool should include an antioxidant, such as the addition of 0.1% alpha-tocopherol (IFRA 2009). Even without an antioxidant, the shelf life of a lavender-containing product should be good for at least 12 months, so long as the essential oils were reasonably fresh when first used.
“Because the fragrance constituents in lavender oil oxidize when exposed to air, lavender oil is pro-oxidant. This enhanced oxidation also increases its irritancy on skin.”
This is partly true. It’s important to realize that in these tests, the essential oil is typically exposed to the air every day for a period of weeks or months. This scenario does not reflect real-world use of lavender oil, though it does show that oxidation will happen eventually. But Paula Begoun is wrong to label lavender oil as a pro-oxidant – it is not, it is an antioxidant that can itself eventually oxidize. That does not make it a pro-oxidant! Pro-oxidants cause oxidation. And, she uses “irritation” here when she means “allergenicity.” They are not the same thing, and the hydroperoxides that can form in lavender oil are potentially allergenic, not irritant.
“Lavender leaves contain camphor, which is known as a skin irritant.”
This assertion smacks of desperation! Lavender oil contains less than 1% of camphor which, anyway, is only a mild irritant. If you have a product containing 1% lavender oil, then you will end up with less than 0.01% of camphor. Even if camphor was a powerful irritant, this would hardly be an issue.
“Research also indicates that other components of lavender, specifically linalool, can be cytotoxic, meaning that topical application causes skin-cell death.”
Here lies the fundamental claim of risk, which however is based on a fundamental misunderstanding. Lavender oil was cytotoxic to human dermal fibroblasts and endothelial cells (skin cells) in vitroat concentrations greater than 0.125%. Linalool (35% of the oil sample) had similar toxicity to the essential oil, while linalyl acetate (51% of the oil sample) was more toxic. Membrane damage was thought to be the mechanism of toxicity (Prashar et al 2004). In this type of assay, the test substance is in direct contact with isolated cells in a petri dish. Without that direct contact, cell membrane damage will not take place at those low dilutions. It’s an in vitro test, and you can’t assume that the same effect will happen when you apply lavender oil to the skin, because the skin has a protective barrier: the stratum corneum. However, even if you applied lavender oil to broken skin, it would still not be equivalent to the test using isolated cells, because the dermis is a complex matrix of tissue that contains those cells.
Any type of in vitro test is only suggestive of a possible effect. You can never assume that the same effect will take place in the living body. It might, it might not. Either the cytotoxicity described above will manifest as irritation, or it will be so negligible as to have no importance. The most telling evidence is the fact that lavender oil has been successfully used in wound healing at 4%, with no adverse effects. Dermatological testing also reveals a lack of irritation. In a 48 hour occlusive patch test on 50 Italian volunteers, undiluted lavender oil produced no adverse reactions. Similarly tested at 1%, it produced no reactions in 273 eczema patients (Meneghini et al 1971). Undiluted lavender oil was slightly irritating to rabbit skin, but was not irritating to mouse or pig skin; tested at 10% on 25 healthy volunteers it was neither irritating nor sensitizing (Opdyke 1976 p451). So if there is any cytotoxicity, it’s not significant.
“It is a must to avoid in skin-care products.”
Skin allergies to lavender oil do happen occasionally, and I know of five cases (not cited here) in the dermatology literature, reported between 1986 and 2000. Considering that it is the most widely used essential oil in aromatherapy (global annual production about 200 tonnes), lavender oil allergy is extremely rare. And, although it is a very low-risk skin allergen (possibly only when oxidized), it is not an irritant. Nor are rose, cedarwood and tangerine. Undiluted lavender oil can work wonders on stings and blemishes, but it should not be applied to large areas of skin simply because it has a drying effect, due to rapid evaporation – the same reason that alcohol is drying.
If you don’t want to use lavender oil – or essential oils in general – that’s fine. But please, don’t mis-represent the science just so you can justify your world-view! Paula is right to draw attention to the possibility of lavender oil oxidation, but this is not a major problem, and is easy to avoid. To be super-safe, use undiluted lavender oil within 12 months of purchase, keep it cool and away from strong sunlight, and add an antioxidant to any product containing it (not needed in soaps).
If you search for negative effects you will surely find them, and it’s easy to become enmeshed in that negativity. I submit that the dermal benefits of lavender oil outweigh the risks to a considerable degree.
References
Bickers D, Calow P, Greim H et al 2003b A toxicologic and dermatologic assessment of linalool and related esters when used as fragrance ingredients. Food & Chemical Toxicology 41:919-942
Cassella S, Cassella JP, Smith I 2002 Synergistic antifungal activity of tea tree (Melaleuca alternifolia) and lavender (Lavandula angustifolia) essential oils against dermatophyte infection. The International Journal of Aromatherapy 12(1):2-15
Cherng J-M, Shieh D-E, Chiang W 2007 Chemopreventive effects of minor dietary constituents in common foods on human cancer cells. Bioscience, Biotechnology & Biochemistry 71:1500-1504
D’Auria FD, Tecca M, Strippoli V et al 2005 Antifungal activity of Lavandula angustifolia essential oil against Candida albicans yeast and mycelial form. Medical Mycology 43:391-396
Edwards-Jones V, Buck R, Shawcross SG et al 2004 The effect of essential oils on methicillin-resistant Staphylococcus aureus using a dressing model. Burns 30:772-777
Ghelardini C, Galeotti N, Salvatore G et al 1999 Local anaesthetic activity of the essential oil of Lavandula angustifolia. Planta Medica 65:700-703
Goiriz R, Delgado-Jimenez Y, Sanchez-Perez J et al 2007 Photoallergic contact dermatitis from lavender oil in topical ketoprofen. Contact Dermatitis 57:381-382
Gould MN, Malzman TH, Tanner MA et al 1987 Anticarcinogenic effects of terpenoids in orange peel oil. Proceedings of the 78th Annual Meeting of the American Association for Cancer Research 28:153
Guba R 1998/1999 Wound healing: a pilot study using an essential oil-based cream to heal dermal wounds and ulcers. The International Journal of Aromatherapy 9(2):67-74
Hartman D, Coetzee JC 2002 Two US practitioners’ experience of using essential oils for wound care. Journal of Wound Care 11(8):317-320
IFRA2009 Standards, including amendments as of October 14th 2009. International Fragrance Association, Brussels. http://www.ifraorg.org
Kerr J 2002 The use of essential oils in wound healing. The International Journal of Aromatherapy 12(4):202-206
Kim HM, Cho SH 1999 Lavender oil inhibits immediate-type allergic reaction in mice and rats. Journal of Pharmacy & Pharmacology 51:221-226
Kunicka-Styczyńska A, Sikora M, Kalemba D 2009 Antimicrobial activity of lavender, tea tree and lemon oils in cosmetic preservative systems. Journal of Applied Microbiology 107:1903-1911
Kunicka-Styczyńska A, Sikora M, Kalemba D 2011 Lavender, tea tree and lemon oils as antimicrobials in washing liquids and soft body balms. International Journal of Cosmetic Science 33:53-61
Meneghini CL, Rantuccio F, Lomuto M 1971 Additives, vehicles and active drugs of topical medicaments as causes of delayed-type allergic dermatitis. Dermatologica 143:137-147
Opdyke DL J 1976 Monographs on fragrance raw materials. Food & Cosmetics Toxicology 14 supplement
Prashar A, Locke IC, Evans CS 2004 Cytotoxicity of lavender oil and its major components to human skin cells. Cell Proliferation 37:221-229
Sakurada T, Kuwahata H, Katsuyama S et al 2009 Intraplantar injection of bergamot essential oil into the mouse hindpaw: effects on capsaicin-induced nociceptive behaviors. International Review of Neirobiology 85:237-248
Sakurai H, Yasui H, Yamada Y et al 2005 Detection of reactive oxygen species in the skin of live mice and rats exposed to UVA light: a research review on chemiluminescence and trials for UVA protection. Photochemical & Photobiological Sciences 4:715-720
Soković M, Glamočlija J, Marin PD et al 2010 Antibacterial effects of the essential oils of commonly consumed medicinal herbs using an in vitro model. Molecules 15:7532-7546
Vakilian K, Atarha M, Bekhradi R et al 2011 Healing advantages of lavender essential oil during episiotomy recovery: a clinical trial. Complementary Therapies in Clinical Practice 17:50-53
Yang SA, Jeon SK, Lee EJ et al 2010 Comparative study of the chemical composition and antioxidant activity of six essential oils and their components. Natural Product research 24:140-151
Zu Y, Yu H, Liang L et al 2010 Activities of ten essential oils towards Propionibacterium acnes and PC-3, A-549 and MCF-7 cancer cells. Molecules 15:3200-3210
Hello Robert,
I met you at the AIA conference in Denver, CO 4 years ago.
I follow your blog and have subscribed to your posts and comments. You are such a wealth of knowledge and I love the way to combine research and common sense.
I have a question about juniperus ashei. My company is called Touch of Earth. I have several products in the marketplace, including an insect repellent called Bugz Be Gone. I am thinking of adding about 1.5% Texas Cedarwood to the formula. The reason for this is I have seen some interesting posts and sites on its use for fleas, ticks and especially bed bugs.
This product has traveled world wide and I have lots of questions from folks about bedbugs these days, especially with the latest news that they may carry MRSA.
I have also read that cedarwood is contraindicated in pregnancy.
I am wondering what your thoughts/opinion of this may be since I have found little to really substantiate this.
Thank you in advance. Nancy
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Hi Nancy,
There is no known reason to avoid any type of cedarwood oil in pregnancy. I have also seen this occasionally, and I don’t know where it comes from, but there’s no scientific basis for it. Texas cedarwood has not been tested on pregnant rodents, which is the way a substance is normally tested for reproductive toxicity, nor have either of its major constituents, thujopsene and alpha-cedrene. However, thujopsene is a sequiterpene, and as such is unlikely to possess any significant reproductive toxicity. Acetyl cedrene, a molecule similar to alpha-cedrene, has been tested on pregnant rats, and there were no adverse fetal effects at the highest oral dose used – 100 mg/kg, equivalent to an adult human ingesting 7 g, or 1/4 oz.
Joanne L. writes:
Hi Robert, I was wondering if you have any thoughts on the following – a short course student of mine works in an essential oil / fragrance suppliers. Recently she poured an unspecified amount of Lemon Scented Myrtle oil over her leg into her shoe which she continued to wear for a number of hours until the end of the day. Her foot and leg turned an orangey red for over a week until she went on holiday and swam in the pool. The same student also spilled lemongrass oil onto her arm at another time. This also turned orangey red but cleared up within a few days. I assume the aldehydes play a part in the discolouration but wonder why the LSM would stain the skin for such a long time?. (I have recommended that she takes milk thistle on a regular basis!) Joanne
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Wow, tough question Joanne! I have never come across this before. Certainly there is a link between lemon-scented myrtle and lemongrass, as they are both very high in citral (about 90% and 80% respectively). The orange-red skin sounds very much like an excess of beta-carotene, and can be caused by eating a LOT of carrots. In the body, beta-carotene is metabolized into retinol, then retinaldehyde (a form of vitamin A) and then retinoic acid. Citral inhibits the enzyme (ALDH1A2) that carries out this last stage (retinaldehyde > retinoic acid). That’s what normally happens. However, if in this person the citral instead inhibited the initial stage of metabolism (beta-carotene > retinol), then an excess of beta-carotene could build up in the skin, so long as some citral was still there. Rather than an individual difference, it’s also feasible that a massive amount of citral might overwhelm metabolic pathways, leading to a “traffic jam” that has the same end result. It’s not a perfect explanation, but it highlights the only link between those essential oils and beta-carotene-like skin. It does not sound like a phototoxic reaction, since these only happen on exposure to sunlight, they don’t spontaneously clear up very quickly, and the discoloration is patchy and tanned rather than orange. But I think that would be the only other possibility.
Q: I have heard that tea-tree oil is one of the only things that can be used to help combat the superbug in hospitals – is this right?
A: I presume you are referring to methicillin-resistant Staphylococcus aureus, or MRSA (there are several other antibiotic-resistant bacteria.) One of the current problems being faced in hospitals worldwide is the increasing resistance of dermally carried MRSA to soaps and ointments intended to eradicate it. These contain active ingredients such as mupirosin, triclosan or chlorhexidine, but bacteria are becoming increasingly resistant to these.
In vitro studies in Australia and the UK have found that tea tree oil is effective against MRSA at concentrations as low as 0.25%. To eradiate MRSA on the skin, creams, ointments and body washes with at least 5% tea tree oil have been successfully used in hospital trials.
Other essential oils including oregano, thyme, patchouli, lemongrass, lavender and geranium are also able to kill MRSA if used in sufficient concentration, but most of the research has been on tea tree oil. Note that systemic MRSA, which can be fatal, is not yet known to be treatable with essential oils. However, in the video clip below you will hear an account of how a man’s life was saved with a mixture of clove, cinnamon, rosemary, lemon and eucalyptus. He had contracted an antibiotic-resistant strain of bacteria in hospital, and conventional treatment had failed.
This question combines two recent topics – lavender oil and cancer – and shows that strange information continues to swirl about…
Beverley H writes
Hi Robert
One of the first references I use when looking up contra-indications is your book with Tony Balaczs – Essential Oil Safety. I understand that you are working on a new edition so no doubt there is more information available than is presently in the book I have.
This morning one of my graduates contacted me. An essential oil supply store in her area has added a caveat to their lavender EO, and say it is now contraindicated for cancer. I have not come across any evidence to support this contra-indication and I was wondering whether if you had. If you have any insight on this I would love to hear it.
Thanks very much. Bev
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Beverley, that’s completely baffling to me! Robert
A Google search for “Avoid high doses of lavender oil during pregnancy because it is a uterine stimulant” produces about 10,500 hits, though none of these will tell you how much constitutes a “high dose”. (Yes, I checked every single one.) Other Google search results about lavender in pregnancy include:
“Lavender oil is a uterine stimulant” – 15,800 hits.
“Lavender is an emmenagogue” – 106,000 hits.
“Lavender should be avoided in the first trimester” – 191,000 hits.
Clearly there is some concern about the safety of lavender oil during pregnancy, although there are also a number of sites where lavender is either absent from “should not be used in pregnancy” lists – in fact it is only rarely found on such lists – or where the oil is actually stated to be safe in pregnancy.
The safety concerns raise questions such as:
Is lavender oil a menstrual stimulant?
Is lavender oil a uterine stimulant?
If it is either or both of these, what is the dose threshold?
Is lavender oil safe to use in pregnancy?
Particular risks that would apply to the first trimester are (a) an increased risk of miscarriage and (b) risk of fetal malformation. However, these risks do not go away after three months, and so limiting avoidance of a reproductively toxic substance to the first trimester only makes sense if there is evidence to support this guideline. But, is lavender oil even reproductively toxic at all?
Emmenagogues
An emmenagogue, or menstrual stimulant, may act by directly stimulating uterine contractions, or through stimulating hormone production. Bartram (1995) defines emmenagogues as: “Plant substitutes for hormones that stimulate the pituitary gland to produce more gonadotrophic hormones. Herbs that initiate and promote the menstrual flow. Most are uterine tonics and stimulants to restore normal function of the female reproductive system. Not used in pregnancy, except when a practitioner has good cause to do so in the first few weeks.” Bartram goes on to list 54 herbs, though lavender is not one of them.
The absence of lavender from Bartram’s list is not surprising since it has not traditionally been regarded as a herb to avoid in pregnancy, or as a uterine stimulant. Culpeper (1652) did say that “lavender….provokes women’s courses”, i.e. stimulates menstruation, but he was referring to spike lavender, not true lavender. In his 1964 text, Dr. Jean Valnet refers to lavender oil as an emmenagogue when internally used, though he gives no contraindication for pregnancy. Lawless (1992) also cites lavender oil as an emmenagogue, though not limited to internal use, and there is similarly no pregnancy contraindication. Franchomme and Pénöel (1990) give no contraindications at all for lavender oil, and do not mention menstrual stimulation but they do list an antispasmodic action for the oil. An antispasmodic action on the uterus suggests a substance that is helpful in menstrual pain, and not one that would stimulate menstruation.
Davis (1999) says that lavender oil is helpful in “reducing…scanty menstruation” and that it should be avoided during the first trimester. It seems likely that Davis was picking up on Valnet’s use of “emmenagogue” and that her mention of first trimester avoidance was an assumption on her part. Tiran (2000) mentions that lavender oil “contains a small amount of the ketone camphor, which can be emmenagogic” and that it “should be used with caution in early pregnancy”. In fact the amount of camphor in true lavender oil is very small and camphor only presents a risk in pregnancy in massive doses (see below).
Herbal safety texts
Three herbal safety texts have concluded that lavender flowers are safe to use in pregnancy, and one of theses includes the essential oil. (These are the only such texts in my possession – there may be others that draw different conclusions.) McGuffin et al (1997) give lavender flowers a “Class 1” rating, meaning generally safe to use, with no contraindication for pregnancy or breastfeeding. They apply this to Lavandula angustifolia (true lavender) L. latifolia (spike lavender), L. stoechas (Spanish lavender) and L. x intermedia (lavandin). Mills and Bone (2005) state that using lavender flowers (L. angustifolia and L. spica) is compatible with breastfeeding, and is safe in pregnancy: “No increase in frequency of malformation or other harmful effects on the foetus from limited use in women.”
The Complete German Commission E Monograph for lavender lists L. angustifolia, both flowers and essential oil, as officially “approved” and with no side effects and no contraindications. This includes internal use of 1-4 drops (20-80 mg) of the essential oil as a daily dose (Blumenthal et al 1998). The Commission E Monographs are generally regarded as the most authoritative source on the safety of herbal medicines.
What the research shows
Camphor is neither reproductively toxic nor abortifacient except in almost fatal doses, and a lethal human dose is approximately 200 mg/kg. No adverse fetal effects were seen from feeding camphor to pregnant rats at 1,000 mg/kg/day, or pregnant rabbits at 681 mg/kg/day (Leuschner 1997). This non-fetotoxic rabbit dose is equivalent to an adult human dose of 48 g (1.6 oz), and a person would have to ingest 24 kg (52.9 lb) of lavender oil to reach that amount of camphor. Therefore the camphor in lavender oil presents no risk.
Linalool is not reproductively toxic. When it was administered by stomach tube to pregnant rats at 250, 500 or 1,000 mg/kg/day, on gestational days 7-17, no fetal toxicity or teratogenicity occurred at any dose level (Politano et al 2008). The high dose is equivalent to an adult human ingesting 70 g of linalool, or approximately 200 g (7 oz) of lavender oil. Linalyl acetate has not been tested on animals for reproductive toxicity.
The research shows that lavender oil (L. angustifolia) is not a uterine stimulant. When used on the isolated rat uterus, it in fact reduced contractions (Lis Balchin and Hart 1999). And, lavender oil has no apparent adverse effects during childbirth. It was one of ten essential oils offered to 8,058 women in an 8-year study at the John Radcliffe Hospital in Oxford, UK. Aromatherapy did, however, reduce the need for pain medication. During the years of the study, the use of pethidine in the study center declined from 6% to 0.2% of women (Burns et al 2000).
One in vitro study found that lavender oil had a very weak estrogenic action in MCF-7 breast cancer cells (Henley et al 2007). However, there is no evidence that lavender oil has any adverse effects on human hormonal activity. In another in vitro study, lavender oil inhibited the growth of MCF-7 cells (Zu et al 2010) suggesting that, while it may bind to estrogen receptor sites in the body, it is not an estrogen mimic, and so does not promote estrogen.
Conclusions
Proving safety in pregnancy is always a challenge, but all the indications are that lavender oil is completely safe to use. It is certainly not a uterine stimulant – in any dose. The online references to lavender oil as a uterine stimulant presumably originated from the few books (probably beginning with Valnet in 1964) that describe it as having an emmenagogic action. An assumption was then made that this was due to a uterine stimulant effect, and a further assumption was made that therefore lavender oil could pose a risk of miscarriage in pregnancy. However, there is no evidence that either lavender flowers or lavender oil stimulate menstruation. Thus are myths conceived. Patricia Davis, I’m sure, felt her caution was well-founded, but with the benefit of hindsight we can see that it was an over-reaction. Erring too heavily on the side of safety has a downside – it creates fear, doubt and confusion.
Finally…while searching the internet for the alleged dangers of lavender oil in pregnancy, I came across this advice on a Vitamins and Health Supplements Guide page: “Pregnant and breastfeeding women should avoid using lavender, as it is a uterine stimulant.” What, breastfeeding women too? The logic of this escapes me. Surely a woman wants her uterus to contract back to it’s normal size after childbirth. (Not that lavender oil would do this anyway.)
References
Bartram T 1995 Encyclopedia of herbal medicine. Grace Publishers, Christchurch UK, p166
Blumenthal M, Busse WR, Goldberg A et al 1998 The complete German Commission E monographs: therapeutic guide to herbal medicines. American Botanical Council, Austin, Texas, p160
Burns EE, Blamey C, Ersser SJ et al 2000 An investigation into the use of aromatherapy in intrapartum midwifery practice. Journal of Alternative & Complementary Medicine 6:141-147
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
Davis P 1999 Aromatherapy an A-Z. CW Daniel, Saffrom Walden, p322
Franchomme P, Pénöel D 1990 L’aromathérapie exactement. Jollois, Limoges, p364
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
Lawless J 1992 The encyclopaedia of essential oils. Element, Shaftsbury, p118
Lis-Balchin M, Hart S 1999 Studies on the mode of action of the essential oil of lavender (Lavandula angustifolia P. Miller). Phytotherapy Research 13:540-542
McGuffin M, Hobbs C, Upton R et al 1997 Botanical safety handbook. CRC Press, Boca Raton, p68
Mills S, Bone K 2005 The essential guide to herbal safety. Churchill Livingstone, St. Louis, p493
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
Tiran D 2000 Clinical aromatherapy for pregnancy and childbirth. Churchill Livingstone, Edinburgh p137
Valnet J 1964 Aromathérapie. Librairie Maloine, Paris, p225 (English translation: Valnet J 1990 The practice of aromatherapy. CW Daniel, Saffron Walden, p144
Zu Y, Yu H, Fu Y et al 2010 Activities of ten essential oils towards Propionibacterium acnes and PC-3, A-549 and MCF-7 cancer cells. Molecules 15:3200-3210
Cory T asks
What do you think is the upper safety level for Ylang-ylang in an oil based perfume? I have looked at the IFRA (International Fragrance Association) guideline and I’m not sure what to think about it. Thanks if you have an answer. I would appreciate it.
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Hi Cory, thank you for your support! I would go along with the IFRA guideline of 0.8%. Ylang-ylang is, relatively speaking, one of the most skin-reactive essential oils. I don’t always agree with IFRA guidelines, but I think this is a good one. Robert
During my mini-tour of Australia in October 2010 I interviewed Ron Guba in Melbourne. Some of this interview is shown above, in which Ron talks about his use of essential oils to treat very small, early-stage skin cancers or pre-cancerous lesions. These were not cancers that required urgent medical intervention.
The main types of skin cancer include:
Solar (or actinic) keratosis (a precursor to SCC)
Squamous celle carcinoma (SCC)
Basal cell carcinoma (BCC)
Melanoma
Melanoma (a.k.a. malignant melanoma) is the rarest, but most virulent type of skin cancer. You can find more detailed information on the different types of skin cancer here. Ron believes that “For solar keratoses, or basal and squamous cell carcinomas in early stages, a number of essential oils would be worthy to trial.” This is a trial formula, for 30 grams total:
Gently melt the beeswax and Jojoba oil together, then add the essential oils and place into containers to cool. This ointment should be applied to affected areas, two to three times per day. Resolution of lesions can take up to six weeks of daily application. If there is no improvement, discontinue use and seek medical advice.
The two photographs below show the complete resolution of a solar keratosis on a woman’s chest. She used the same formulation as above, but with 50% essential oil. Because of the irritation she experienced, Ron is now using the essential oils at 33%. This is her account of using the formulation: “The second photo doesn’t show it so well but the spot had nearly halved in size, the top half is gone (the photographer didn’t tell me the ruler wasn’t in line!). I can’t notice any remaining mark looking in the mirror but in the final photo there could be the faintest pink mark where it was. I used the oil twice/day. I got some skin irritation after about a week of using it. I considered diluting it but instead applied a little sweet almond oil to the surrounding area when I applied it. The skin irritation resolved after a day or two of doing that. After 2 weeks I noticed part of the keratosis was just disappearing. The rest was completely gone within another 10 days. A very good result considering the skin specialist told me if it was removed it would leave a large white scar.”
Solar keratosis, day 0
In post-video emails, Ron has added the following information: Another long time aromatherapy friend (a red-head) used the 50% blend on a diagnosed BCC – about 3mm on his upper right chest. Six weeks to full resolution. The two other cases were from afar. One had a small BCC on his right shoulder and reported to me that the lesion had cleared after four weeks. The other had a small SCC arising from an actinic keratosis on his left hand. He had multiple actinic keratoses and had had a number of these removed with cryosurgery and some SCCs were surgically excised. I heard from him some months later that the lesion had healed after ‘some weeks’.
Solar keratosis, day 26
In the end, it is an experimental formula. As I said, it is worthy to trial on small SCCs, BCCs (BCCs being the least risky) and solar keratoses when there is not an immediate need for treatment. If there is no result in six weeks, move on to medical treatment. Part of Elson’s work on ‘exogenous isoprenoids’ were done on melanoma cell lines in vitro and many of the compounds like limonene, geraniol, etc. were effective at arresting growth and inducing apoptosis at low use levels. Of course, it would be interesting to see if such formulae could actually be truly effective on early diagnosed melanomas, but too risky to suggest.
What is great about the essential oil treatment is the lack of pain, and the fact that it does not create a woundwith consequent scarring as compared to conventional treatments. I will be making a formula soon for a woman with a small patch of Bowen’s Disease – a pre-cancerous form of squamous carcinoma. I may also extract some powdered frankincense resin with the essential oils, as the boswellic acids in the resin have some useful anti-cancer properties.
Ron Guba is Australia’s leading proponent of aromatic medicine, having studied and practiced since the early 1980s.
Completing his diploma in Phytotherapy and Aromatic Medicine in 1988 in France, Ron began Essential Therapeutics, a company devoted to providing therapeutic-grade essential oils to health practitioners.
Ron founded the Centre for Aromatic Medicine in 1989, to provide education and training in the practice of aromatic medicine and aromatherapy.
Ron is a founding member and past chairman of both the International Federation of Aromatherapists (Australia) andthe Australian Aromatic Medicine Association. He writes, and lectures extensively in Australia and overseas.
Note
In animal research, experimental skin cancers have been successfully treated with sandalwood oil at 5% (Dwivedi and Abu-Ghazaleh 1997,Dwivedi and Zhang 1999), tea tree oil at 10% (Greay et al 2010).
Dwivedi C, Abu-Ghazaleh A 1997 Chemopreventive effects of sandalwood oil on skin papillomas in mice. European Journal of Cancer Prevention 6:399-401
Dwivedi C, Zhang Y 1999 Sandalwood oil prevent skin tumour development in CD1 mice. European Journal of Cancer Prevention 8:449-455
Greay SJ, Ireland DJ, Kissick HT et al 2010b Inhibition of established subcutaneous murine tumour growth with topical Melaleuca alternifolia (tea tree) oil. Cancer Chemotherapy & Pharmacology 66:1095-1102
How many of your favourite oils can you mix together before you lose the plot, so to speak? And are, say, three stress-relieving oils blended together more effective than one on its own?
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If you want something for, say, aching muscles or sinus congestion, then “fragrance impact” is less important. However, if you are looking for an ideally-proportioned, wonderfully-smelling blend, most people find that if they mix more than 4 or 5 oils together they begin to, as you say, lose the plot.
You have to remember that each essential oil is composed of some 50 to 100 aromachemicals, and so when you blend three oils together you are actually blending a couple of hundred fragrance materials. Blending many oils together successfully is possible, and I routinely use between 10 and 20 oils in blends for products. However, the relative quantities have to be very precise, and losing the plot is, if anything, much easier.
Three stress-relieving oils blended together are probably going to be more effective than a single oil, maybe not hugely, but blends do tend to be more effective. I think if you achieve “fragrance synergy” then you are probably also going to achieve therapeutic synergy. Plus, whoever chooses the oils and makes the blend puts their positive energy into it, so probably it will have more power than any single oil.
Medical disclaimer: The contents and information on this website are for informational use only, and are not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you read on this website. Robert Tisserand does not give medical advice nor does he engage in the practice of medicine. He will not be liable for any direct, indirect, consequential, special, exemplary, or other damages arising from the application of information on this website.
A Google search for “Avoid high doses of lavender oil during pregnancy because it is a uterine stimulant” produces about 10,500 hits, though none of these will tell you how much constitutes a “high dose”. (Yes, I checked every single one.) Other Google search results about lavender in pregnancy include:
The absence of lavender from Bartram’s list is not surprising since it has not traditionally been regarded as a herb to avoid in pregnancy, or as a uterine stimulant. Culpeper (1652) did say that “lavender….provokes women’s courses”, i.e. stimulates menstruation, but he was referring to spike lavender, not true lavender. In his 1964 text, Dr. Jean Valnet refers to lavender oil as an emmenagogue when internally used, though he gives no contraindication for pregnancy. Lawless (1992) also cites lavender oil as an emmenagogue, though not limited to internal use, and there is similarly no pregnancy contraindication. Franchomme and Pénöel (1990) give no contraindications at all for lavender oil, and do not mention menstrual stimulation but they do list an antispasmodic action for the oil. An antispasmodic action on the uterus suggests a substance that is helpful in menstrual pain, and not one that would stimulate menstruation.
