“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 vitro at 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.
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