Personal Care Truth or Scare

cosmetic safety information based on scientific research

You are here: Home / Archives for lavender oil

lavender oil

Lavender Oil and Negative Innuendo

By 27 Comments

In a recent blog post an Environmental Working Group (EWG) research assistant suggests that lavender oil may be unsafe, saying: “the science is still evolving and safety can’t be assumed.” The science is still evolving? Isn’t that true of anything? Are we just sowing the seeds of doubt here?

I have written a number of posts about the EWG and sloppy science. Their modus operandi involves highlighting negative information, along with liberal use of the phrase “has been linked to”. Factual information is so often distorted that their reputation in scientific circles is all but worthless. I have never read an EWG report in which both sides of an argument are presented. The problem I have with this approach is that the EWG audience is consumers, who have neither the scientific training nor the knowledge and expertise to challenge what is being said. In spite of this many do, because they instinctively feel that something is not right.

Skin allergy
Lavender oil “has been linked to” allergic reactions, it’s true. But how strong is that link? After all, if you look hard enough, you will find at least one allergic reaction report for almost every substance used in cosmetics. Cherry picking a few negative studies is not a useful way to help consumers assess product safety. What we need is a comparative rating that clearly flags high-risk ingredients, along with practical safety guidelines.

“Allergy epidemics” have occurred in the past, most often with preservatives. As use becomes more extensive, adverse reactions escalate, and eventually the substance is either banned or restricted. In spite of widespread use, this is not happening with lavender, which has been the most popular essential oil for aromatherapy use since the 1970s.

The EWG post is written by Swati Sharma. She tells us that: “Despite its ubiquity in cosmetics, researchers in Japan who compared eight essential oils found that lavender caused the greatest number of skin allergies.” No it did not, unless you only look at two of the nine years of the study! The Japanese researchers tested six essential oils, one absolute and two essential oil constituents. The essential oil that produced the greatest number of adverse reactions was ylang-ylang (tested at 5%), followed by geranium (tested at 20%) followed by lavender (also tested at 20%). And since all the other substances were tested at either 5% or 2%, the relative risk of each cannot be compared anyway. The higher the test concentration, the greater will be the number of reactions. And, the Japanese subjects were all dermatology patients “suspected of cosmetic dermatitis”, an especially high-risk group.

Considering that the lavender oil was patch tested at 20% in a high-risk population, and that only 1.4% (21 of 1,483) of patients had an adverse reaction, this does not suggest a significant allergen. Other research points to lavender oil presenting a very low risk. When 50 healthy volunteers were patch tested with the undiluted oil, there were no reactions (Meneghini et al 1971). Similarly, none were produced in 25 volunteers tested with lavender at 10% (Opdyke 1976 p451). In a study of 200 dermatitis patients in Poland, none were sensitive to 2% lavender oil (Rudzki et al 1976). In a Danish study, two of 217 dermatitis patients (0.9%) tested positive to 2% lavender oil (Veien et al 2004). Tested at 1%, lavender oil produced no reactions in 273 dermatitis patients (Meneghini et al 1971).

Taken together, these results show that two of 690 dermatitis patients (0.3%) reacted to lavender oil when patch tested at 1% or 2%. However, extrapolating from patch test data on dermatology patients to the general population is notoriously difficult (especially since the conditions of patch testing exaggerate risk) and the actual number of people with adverse reactions to lavender is very much less than 0.3%. Over a 15 year period (1986-2000) there have only been five cases of lavender oil allergy reported worldwide (Brandão 1986, De Groot 1996, Keane et al 2000, Schaller & Korting 1995, Selvaag et al 1995) and three were people with multiple allergies. This is in contrast to millions of bottles of undiluted lavender oil being sold to consumers per annum, and millions more personal care products containing lavender oil.

From all of the above we can conclude that a 20% concentration of lavender oil might be risky for Japanese consumers with cosmetic allergies, but 2% is not a risk to anyone, and even undiluted lavender is safe to use on healthy skin. Not only is lavender a very low-risk skin allergen, it possesses anti-allergic properties. Topically applied, the oil inhibited immediate-type allergic reactions by inhibiting the release of histamine from mast cells (Kim et al 1999). How is this possible? Probably because in most cases, allergies only occur from the use of oxidized lavender oil. The unoxidized oil is anti-allergic, and is even moderately antioxidant (Wei and Shibamoto 2007).

Oxidation
Sharma tells us that linalyl acetate, a major constituent of lavender oil, can oxidize in the presence of atmospheric oxygen, “forming allergens that can cause contact dermatitis” (Sköld et al 2008). Indeed it can, as can linalool, the other major constituent of lavender oil (Sköld et al 2004). However, these are theoretical risks, not actual risks, and lavender oil oxidation is a process that takes many months, even years. What this research suggests is that products containing lavender oil should be protected from oxidation by the addition of antioxidants, and that very old products should be discarded. The International Fragrance Association (IFRA) does not have a regulation for lavender oil, but it does for linalool. Referring to linalool-rich essential oils, the IFRA guideline recommends the addition of an antioxidant: “The addition of 0.1% BHT or a-tocopherol has shown great efficiency” (IFRA 2009).

Next, Sharma informs us that “lavender oil may be toxic to human skin cells” though curiously no reference is given (it’s Prashar et al 2004). I addressed this issue in a previous post about lavender, in which I explain how we know that the oil is not a skin irritant, and is not toxic to skin cells when applied to human skin.

Hormone disruption
Finally, Sharma raises the question of lavender oil and hormone disruption, an issue I have also addressed previously, in this article. To sum up, there was no established link between lavender oil and breast growth in three pre-perbertal boys, but lavender oil did show a weak in vitro estrogenic action in two (of the four possible) types of in vitro test for estrogenic activity (Henley et al 2007). None of this establishes that lavender oil disrupts hormones. To quote Diel et al (1999): “…even a combined use of several in vitro test systems is not able to predict the occurring action of a substance in the organism.” In other research, lavender oil was significantly toxic to human breast cancer cells (Zu et al 2010) suggesting that it would prevent breast cancer, and not increase risk.

Summary points
Consumer products containing lavender oil may benefit from the addition of an antioxidant, such as alpha-tocopherol. This should be used at 0.1-0.2% (note that using more is not more effective).

Bottles of lavender oil, or products containing lavender oil, that are more than 12 months old (after first use) should be discarded if they no longer smell fresh.

There is a theoretical risk of skin allergy from lavender oil, but this risk is extremely low. Restricting the percentage of lavender oil in leave-on products (skin creams, lotions, gels) to 2% would be over-cautious, but combined with the addition of an antioxidant, will make a product super-safe.

Lavender oil has a weak in vitro estrogenic activity, but there is no reason to believe that this translates to a hormone-disrupting effect in humans.

References
Brandão FM 1986 Occupational allergy to lavender oil. Contact Dermatitis 15:249-250

De Groot AC 1996 Airborne allergic contact dermatitis from tea tree oil. Contact Dermatitis 35:304-305

Diel P, Smolnikar K, Michna H 1999 In vitro test systems for the evaluation of the estrogenic activity of natural products. Planta Medica 65:197-203

Keane FM, Smith HR, White IR et al 2000 Occupational allergic contact dermatitis in two aromatherapists. Contact Dermatitis 43:49-51

Henley DV, Lipson N, Korach KS et al 2007 Prebubertal gynecomastia linked to
lavender and tea tree oils. New England Journal of Medicine 365: 479-485

IFRA 2009 Standards, including amendments as of October 14th 2009. International Fragrance Association, Brussels. http://www.ifraorg.org

Kim HM, Cho SH 1999 Lavender oil inhibits immediate-type allergic reaction in mice and rats. Journal of Pharmacy & Pharmacology 51:221-226

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 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

Rudzki E, Grzywa Z, Brud WS 1976 Sensitivity to 35 essential oils. Contact Dermatitis 2:196-200

Schaller M, Korting HC 1995 Allergic airborne contact dermatitis from essential oils used in aromatherapy. Clinical & Experimental Dermatology 20:143-145

Selvaag E, Holm JO, Thune P 1995 Allergic contact dermatitis in an aromatherapist with multiple sensitizations to essential oils. Contact Dermatitis 33:354-355

Sköld M, Börje A, Harambasic E et al 2004 Contact allergens formed on air exposure of linalool. Identification and quantification of primary and secondary oxidation products and the effect on skin sensitization. Chemical Research in Toxicology 17:1697-1705

Sköld M, Hagvall L, Karlberg AT et al 2008 Autoxidation of linalyl acetate, the main component of lavender oil, creates potent contact allergens. Contact Dermatitis 58:9-14

Sugiura M, Hayakawa R, Kato Y et al 2000 Results of patch testing with lavender oil in Japan. Contact Dermatitis 43:157-160

Veien NK, Rosner K, Skovgaard GL 2004 Is tea tree oil an important contact allergen? Contact Dermatitis 50:378-379

Wei A, Shibamoto T 2007 Antioxidant activities and volatile constituents of various essential oils. Journal of Agricultural & Food Chemistry 55:1737-1742

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

 

 

Lavender Oil – Skin Savior or Skin Irritant?

By 25 Comments

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%.

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.

“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.

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

Gattefossé RM 1993 Gattefossé’s aromatherapy.  CW Daniel, Saffron Walden

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

IFRA 2009 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

Gattefossé’s Burn

By Leave a Comment

“In 1910 French chemist and scholar René-Maurice Gattefossé discovered the virtues of the essential oil of lavender. Gattefossé badly burned his hand during an experiment in a perfumery plant and plunged his hand into the nearest tub of liquid, which just happened to be lavender essential oil. He was later amazed at how quickly his burn healed and with very little scarring. This started a fascination with essential oils and inspired him to experiment with them during the First World War on soldiers in the military hospitals.”

If you’re in the aromatherapy biz, you are probably familiar with the story. The above version appears, word-for-word, on several websites, and the same basic tale on many. I’m fascinated by the appearance of “In 1910” in the story which, although true, is quite a recent development. There’s only one original source of that date: Monsieur Gattefossé, but whoever wrote the above clearly did not read Gattefossé’s own account. Ah well, that’s how it goes with rumours.

The story is basically correct, apart from the instinctual plunging of the hand into the nearest available liquid, which is total fiction. Anyway, who leaves large containers of lavender oil lying around unlidded? Certainly not a perfume chemist like Gattefossé.

It’s remarkable how the mythical aspects of the tale have continued, long after the publication in English, in 1993, of his 1937 book Aromathérapie (by the way, this was the first appearance of the word “aromatherapy” in print). Yes, he burned his hand in his laboratory and yes, he treated it with lavender oil, but this was not a eureka-like, lucky-chance moment. It would be great if it was true. Translated from French, this is Gattefossé’s own description of the incident, and this is all he has to say about it:

“The external application of small quantities of essences rapidly stops the spread of gangrenous sores. In my personal experience, after a laboratory explosion covered me with burning substances which I extinguished by rolling on a grassy lawn, both my hands were covered with a rapidly developing gas gangrene. Just one rinse with lavender essence stopped “the gasification of the tissue”. This treatment was followed by profuse sweating, and healing began the next day (July 1910).”

His application of lavender oil was clearly an intentional act, and the result impressed him greatly, and possibly saved his life. It was a special moment for him, and for aromatherapy.

Gas gangrene is a potentially fatal infection, and was the cause of many amputations and deaths in the First World War. Although traumatic gas gangrene is rare today, 25% of those who contract it still die. It is caused by infection of a wound, most commonly by Clostridium perfringens. Onset is rapid and dramatic (though it normally takes 1-4 days from the time of infection), with bacterial toxins causing tissue death and subcutaneous swelling and gas. Sweating is one of the early symptoms of infection. Since the bacterium is most commonly found in soil, Gattefossé’s rolling in the grass might have precipitated the infection.

While the incident did not initiate his study of aromatherapy, it was certainly a strong hint – a definite push in a direction he was already headed. Subsequently he collaborated with a number of doctors who treated French soldiers for war wounds using lavender and other essential oils. The accounts of these cases constitute a large part of his text.

Microbiological research shows that a number of essential oils are active against strains of Clostridium perfringens including winter savory (Satureja Montana) lemongrass (Cymbopogon citratus) lemon myrtle (Backhousia citriodora) lemon tea tree (Leptospermum petersonii) and tea tree (Melaleuca alternifolia). Some of these are being given to factory-farmed chicken, which are susceptible to Clostridium perfringens-related disease. The essential oils don’t have the same drawbacks as antibiotics.

No-one has yet tested lavender oil against Clostridium perfringens, although we do know that lavender oil can inhibit the mechanism (known as quorum sensing) through which bacteria “decide” to release their toxins. Gattefossé’s use of lavender oil was not so much a happy accident as an instinctual success. It also helped make him famous, and we still remember the incident 101 years later. Serendipity, however you look at it.

References
De Oliveira TL, De Araújo Soares R, Ramos EM et al 2011 Antimicrobial activity of Satureja montana L. essential oil against Clostridium perfringens type A inoculated in mortadella-type sausages formulated with different levels of sodium nitrite. International Journal of Food Microbiology 144:546-555

Gattefossé R-M, Tisserand RB (ed.) 1993 Gattefossé’s aromatherapy: the first book on aromatherapy. CW Daniel, Saffron Walden, p 87

Shanmugavelu S, Ruzickova G, Zrustova J et al 2006 A fermentation assay to evaluate the effectiveness of antimicrobial agents on gut microflora. Journal of Microbiological Methods 67:93-101

Szabó MA, Varga GZ, Hohmann J et al 2010 Inhibition of quorum-sensing signals by essential oils. Phytotherapy Research 24:782-786

Wannissorn B, Jarikasem S, Siriwangchai T et al 2005 Antibacterial properties of essential oils from Thai medicinal plants. Fitoterapia 76:233-236

No Suspension of Disbelief Required

By 2 Comments

Unlike the practice of acupuncture or homoeopathy, the belief system underlying the use of plants as medicines is not necessarily different to the use of single substances, or “drugs”. For sure, herbalist and doctor may have very different approaches to healing disease, and the concept of synergy is one that remains almost totally unexplored in conventional medicine (perhaps a missed opportunity…).

But, medicines of both types can be described using similar pharmacological terminology – anti-inflammatory, analgesic, antibacterial and so on. Therefore, no suspension of disbelief is required – no fundamental paradigm shift  – no reinvention of the laws of physics or chemistry. Yes, there exist a number of energetic systems, Ayurveda, TCM and others, but plant medicine is also chemical medicine, even if it is somewhat complex, involving as it does the synergistic and antagonistic interactions of many substances.

Lavender oil is often described as relaxing, calming, sedative. There is no argument about what these terms mean, although “sedative” might be inappropriate, as the research suggests that lavender oil improves sleep quality, but is not as strong a sedative as prescription sleeping pills. The effect of lavender oil has been described as “weak”, or “poor” by those firmly within the allopathic camp. This may be intended as criticism, but really there is no argument here – yes, as a “sedative”, lavender has only a mild effect.

However, as an anxiolytic (anti-anxiety) medicine, its effect is more notable, and lavender oil capsules have recently been licensed for use in Germany, under the brand name Lasea. The related research – see below – describes the medicine under the name Silexan, but basically it is lavender oil in capsule form. And no, it’s not a placebo effect.

This-for-that plant medicine (this remedy for that problem) is perhaps not the holistic ideal, but it’s still hugely important, and I would much rather advocate the use of lavender oil than benzodiazepines. Most doctors won’t promote Lasea, any more than they have promoted Mintec or Colpermin (both peppermint oil capsules that have been around for decades). Yes, “we” can provide “you” with good evidence that plant medicines can be both safe and effective. But will “you” take any notice when we do?

There are two distinct challenges – the problem of “scientism” – I believe only in science, and plant medicine does not sound like science to me – and the problem of the pharmaceutical companies’ stranglehold on healthcare providers. But, it’s time for people to start taking notice of the opportunities now being made available. Don’t suspend your disbelief, just your anxiety.

Kasper S, Gastpar M, Müller WE et al 2010 Silexan, an orally administered Lavandula oil preparation, is effective in the treatment of ’subsyndromal’ anxiety disorder: a randomized, double-blind, placebo controlled trial. International clinical psychopharmacology 25:277-287

Woelk H, Schläfke S 2010 A multi-center, double-blind, randomised study of the Lavender oil preparation Silexan in comparison to Lorazepam for generalized anxiety disorder. Phytomedicine 17:94-99

Hidden Benefits

By 3 Comments

Reports on the effects of aromatherapy massage on pain, anxiety and depression in cancer patients are inconsistent, with some finding significant effects, and others not. One that did find an effect (Imanishi et al 2007) was authored by a group of researchers from four Japanese Universities. In 12 patients with breast cancer, anxiety was significantly reduced over a 4 week period. The patients received two 30 minute massage sessions each week, using diluted sweet orange, lavender and sandalwood oils. STAI (State-Trait Anxiety Inventory) scores were significantly lower after a massage session than before it, and the reduction was progressive. Even one month after the last session, anxiety levels remained low.

One possible reason for the positive outcome is that a blend of oils was used – many studies use a single oil, most commonly lavender. Another interesting finding was that the aromatherapy massage increased lymphocytes, demonstrating an improvement in immune function. But was the positive effect on the immune system due to the fact that the patients were feeling less anxious, or was it a direct immunological action?

In an earlier study (Kuriyama et al 2005), some of the same researchers measured STAI before and after a single 30 minute massage session, in 11 volunteers. Although there was a significant anxiety reduction after aromatherapy massage, there was a similar reduction after plain oil massage. But, only the aromatherapy massage increased white blood cell counts, with increases in CD8+ and CD16+ lymphocytes. In the 2007 report, CD8+ lymphocytes were also increased, but CD16+ lymphocytes were reduced. However, the 2005 report used a different oil blend – lavender, cypress, marjoram and tea tree.

What this suggests is that anxiety can be reduced by aromatherapy massage, but whether an effect takes place, and if so what effect, may depend on the specific essential oils used. Evidence of anxiety reduction from aromatherapy massage is not exactly riveting news. What is more interesting, is that it can significantly affect white blood cell count, and this is not because of the anxiety reduction. If it was, white blood cells would also have increased in the plain oil massage group in the 2005 study, and they did not. In this instance, it’s the oils, not the massage. I’m just saying…

Yes, they were very small studies, but the results imply that the benefits of aromatherapy massage go some way beyond relaxation. You will find both articles here.

Ask the Experts

By 2 Comments

Question:

My friend is a breast cancer survivor.  She had another friend, also a breast cancer survivor tell her she should not use any products containing essential oils because essential oils contain estrogen and it is a build up of estrogen in the body which causes cancer.

I would love a scientific response to this as I believe it to be a misconception that is spreading.

Thank-you

Kris

Answer:

Kris –

No essential oils contain estrogen. Some essential oils contain compounds that have very weak, estrogen-like effects in in vitro tests. However, in the case of tea tree oil, for example, the estrogen-like compounds do not penetrate human skin, and a hormonal effect from dermal application of the oil is therefore impossible.

The National Cancer Institute states that “Applying lavender and tea tree oils to the skin over a long period of time has been linked in one study to breast enlargement in boys who have not yet reached puberty.”  This is incorrect on two counts: (1) neither lavender oil nor tea tree oil were applied to the skin in any of the three cases.  Various unidentified products (such as hair gel) were used, that were alleged to contain either lavender oil or tea tree oil.  However, no evidence was presented to show that the products used by the boys did actually contain either essential oil.  Also, it is not known whether the personal care products used actually caused the gynecomastia, since (b) they were NOT used over a long period of time.  This sheds considerable doubt on any causal connection, and the study has drawn criticism from the scientific community for its lack of rigor.

For a full account of the facts and critique, read below “Neither Lavender Oil nor Tea Tree Oil Can Be Linked to Breast Growth in Young Boys“.

Introduction
In 2007, a correlation was alleged between commercial products containing lavender and tea tree oils and breast growth in young boys. Three cases were seen in boys aged 4-7, who had all been using such products. In each case, the breast growth reduced to normal parameters within several months of ceasing to use the products. Subsequent laboratory testing showed that both essential oils had estrogen-like properties (Henley et al 2007).  In the report, no information was given about any of the product ingredients, and there is scant information on product use. No analysis was carried out to confirm or rule out the presence of essential oil constituents.

Case One
In the first case, “The patient’s mother reported applying a “healing balm” containing lavender oil to his skin starting shortly before the initial presentation.” No further details of the product or its use are given, but a healing balm sounds like something that might only be applied to a small area of skin. If so, then it is unlikely that any ingredient couldhave entered the boy’s blood in sufficient concentration to cause gynecomastia within a short time period.

Case two
In the second case, a styling hair gel was applied to the hair and scalp every morning, along with regular use of a shampoo. Both tea tree oil and lavender oil are cited on the ingredient list of both products.  In a subsequent website report, it is claimed that the two hair products used in this case were manufactured by Paul Mitchell®, and that these were analyzed by a competitor.  The shampoo was said to contain “very low concentrations” of tea tree oil, and the
content in the hair gel was “virtually undetectable”.  Lavender oil concentration was not checked (Neustaedter 2007).

Dermal absorption of fragrance from shampoo application has been estimated to be 80 times less than that from body lotion (Cadby et al 2002) and tea tree oil constituents are poorly absorbed by human skin. In one study, only 3% of the essential oil volume, applied as a 20% concentration in ethanol, was absorbed in a 24 hour period (Cross and Roberts 2006). If the website report is reliable, considering that shampoo is a wash-off product, and that there was only a negligible amount of tea tree oil in the hair gel, tea tree oil can be ruled out as a possible cause of this boy’s gynecomastia.  However, liberal use of a hair gel rich in lavender oil could result in moderate dermal absorption of lavender oil constituents (Cal 2006).

Case Three
The third case involved “lavender-scented soap, and intermittent use of lavender-scented commercial skin lotions”. This sounds as if there may not be very much natural lavender oil present. Since soap is a wash-off product, and use of the skin lotions is described as “intermittent”, whether any meaningful absorption of lavender oil constituents took place at all seems doubtful.As dermal absorption of soap fragrance is some 266 times less than that from body lotion, it is virtually impossible that the fragrance in a soap could be absorbed in sufficient quantity to cause any physiological effect (Cadby et al 2002).

Of great interest is the statement that, in this third case, a fraternal twin used the same skin lotions, but not the soap, and did not develop gynecomastia. It would be reasonable to assume that, since the soap could not be responsible for the effect, and since the twin used the lotions without any problem, the gynecomastia in this third case must have been due to some cause other than essential oils.

The in vitro evidence shows weak but definite endocrine disrupting effects for both lavender and tea tree oils.  The second case was the only one in which tea tree oil was involved. Tea tree oil was tested because it was deemed to be “chemically similar” to lavender oil. However, apart from the fact that both are essential oils, they have very little in common chemically.  The composition of the essential oils tested is not given, nor is any other information about them, apart from the supplier. Since they do not appear to be organically grown, biocide content is a possibility.

Discussion
It is unusual in such reports not to name the products suspected as being responsible for the effects in question. In the circumstances, it is also curious that the labeled ingredients were not cited. It is even more surprising that no attempt was made to ascertain, retrospectively, whether any constituents of lavender or tea tree oil were detectable, and if so at what concentrations. If the products are not named, no one else can test them either.

Subsequent research has confirmed that tea tree oil does show weak in vitro estrogenic action in MCF-7 cells (Nielsen 2008). However, none of the tea tree oil constituents that penetrate human skin (terpinen-4-ol, α-terpineol, 1,8-cineole) act as estrogens, either singly or in combination, in fact α-terpineol is anti-estrogenic (Cross et al 2008, Nielsen 2008, Reichling et al 2006). Tea tree oil is not a skin penetration enhancer, and in one study reduced the quantity of other substances (benzoic acid and methiocarb) crossing the dermal barrier (Nielsen and Nielsen 2006).

The two main lavender oil constituents, linalool and linalyl acetate, are absorbed by human skin (Jäger et al 1992). However, transcutaneous absorption from fragrances takes some time. The amount that could find its way into the blood from a wash-off product such as a shampoo or soap is negligible, because the time of skin contact is so short.  Skin absorption from tea tree oil and lavender oil constituents is measured in hours rather than minutes, and in some instances even leave-on products result in minimal dermal penetration (Cal 2006, Reichling 2006).

No attempt was made to identify the constituent(s) responsible for the in vitro effect, but it is reasonable to expect that any hormonal action in an essential oil would be due to one or two constituents, or even contaminants. It is noteworthy that, while in vitro hormonal effects from essential oil constituents have been previously reported, these are generally very weak, and have been estimated as being at least 10,000 times less potent than 17β-estradiol (Howes et al 2002). Very weak activity is typical of estrogens from plant sources (Chadwick et al 2006).

There is no evidence that the effect seen in vitro would take place in vivo, and much more research would be needed before any such conclusion could be drawn. The report mentions that none of the boys had been exposed to any known endocrine disruptor, such as medications, oral contraceptives(!), marijuana or soy products. However, no mention is made of other known endocrine disruptors, including organochlorine pesticides, PCBs, polychlorinated dioxins, alkyl phenols, pthalates and parabens (Darbre 2006). Both pesticides and phthalates have been found in essential oils, and both phthalates and parabens are commonly found in cosmetic products.

Personal care products have been identified as contributing to phthalate body burden in adult men (Duty et al 2005); phthalates are commonly found in cosmetic products, and are potential hormone disruptors (Darbre 2006). DEHP, for example, has hormone disrupting effects in both male and female rats (Lovekamp-Swan and Davis 2003, Parks et al 2000), and high levels of several phthalates were found in the blood of 28 of 41 prepubertal girls (68%) with premature breast development compared to only 1 of 35 controls (3%) (Colón et al 2000).

It is, therefore, entirely possible that other ingredients or contaminants in the products caused the gynecomastia. Pesticides, PCBs and dioxins are found in the environment, often in food, and it is also possible that a local surge of environmental hormone disruptors caused these cases in Colorado.

Conclusions
As the report states, breast growth in pre-pubertal boys is extremely uncommon, yet three cases were reported within a short period of time, and all in the same clinic.  Considering that some 200 tonnes per annum are produced of both lavender oil and tea tree oil, that most of this goes into personal care products, and that very little of the evidence presented for these three cases is convincing, the initial press reports of caution were premature, as are the cautions now found on many websites.

Even if one or more of these cases was linked to product use, any connection with either lavender or tea tree oil is unproven. Other endocrine disrupting ingredients in the products could have played a role. Furthermore, we do not know what other factors, such as dietary or environmental, may have played a part.

The in vitro work reported by Henley et al (2007) does indicate a hormonal effect.  However, this cannot be extrapolated to estimate actual human risk, especially without knowing more about the essential oil constituents causing the in vitro effects seen, the amounts being applied to the body, and their bioavailability.

No connection was established between the in vitro work and the three cases, and the evidence for tea tree oil having an effect on prepubertal gynecomastia is non-existent.  Phytoestrogens generally have a very weak hormonal activity, and it is implausible that the amounts of essential oil that enter the body from product use would have a significant effect.

References

Cadby PA, Troy WR, Vey MG 2002 Consumer exposure to fragrance ingredients:  providing estimates for safety evaluation.  Regulatory Toxicology & Pharmacology 36:  246-252

Cal K 2006 How does the type of vehicle influence the in vitro skin absorption and elimination kinetics of terpenes? Archives of Dermatological Research 297: 311-315

Chadwick LR, Pauli GF, Farnsworth NR 2006 The pharmacognosy of Humulus lupulus L. (hops) with an emphasis on estrogenic properties. Phytomedicine 13: 119-131

Colón I, Caro D, Bourdony CJ et al 2000 Identification of phthalate esters in the serum of young Puerto Rican girls with premature breast development. Environmental Health Perspectives 108:895-900

Cross S, Roberts M 2006 In-vitro human epidermal membrane penetration of tea tree oil components from pure oil and a 20% formulation. A report to RIRDC (Australian Rural Industry Research and Development Corporation)

Cross SE, Russell M, Southwell I et al 2008 Human skin penetration of the major components of Australian tea tree oil applied in its pure form and as a 20% solution in vitro. European Journal of Pharmaceutics & Biopharmaceutics 69:214-222

Darbre PD 2006 Environmental oestrogens, cosmetics and breast cancer. Best Practice & Research Clinical Endocrinology & Metabolism 20: 121-143

Duty SM, Ackerman RM, Calafat AM et al 2005 Personal care product use predicts urinary concentrations of some phthalate monoesters. Environmental Health Perspectives 113:1530-1535

FMA 2007 http://www.fmafragrance.org/sub_pages/020107henleyresponse.pdf

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

Howes M-JR, Houghton PJ, Barlow DJ et al 2002 Assessment of estrogenic activity in some common essential oil constituents. Journal of Pharmacy & Pharmacology 54:1521–1528

Jäger W, Buchbauer G, Jirovetz L et al 1992 Percutaneous absorption of lavender oil from a massage oil. Journal of the Society of Cosmetic Chemists 43:49-54

Lovekamp-Swan T, Davis BJ 2003 Mechanisms of phthalate ester toxicity in the female reproductive system. Environmental Health Perspectives 111:139-145

Neustaedter R 2007 http://www.cureguide.com/Natural_Health_Newsletter/Lavender_Dangers/lavender_dangers.html

Nielsen JB 2008 What you see may not always be what you get – bioavailability and extrapolation from in vitro tests. Toxicology in Vitro 22:1038-1042

Nielsen JB, Nielsen F 2006 Topical use of tea tree oil reduces the dermal absorption of benzoic acid and methiocarb. Archives of Dermatological Research 297:395-402

Parks LG, Ostby JS, Lambright CR et al 2000 The plasticizer diethylhexyl phthalate induces malformations by decreasing fetal testosterone synthesis during sexual differentiation in the male rat. Toxicological Sciences 58:339-349

Reichling J, Landvatter U, Wagner H et al 2006 In vitro studies on release and human skin permeation of Australian tea tree oil (TTO) from topical formulations. European Journal of Pharmaceutics & Biopharmaceutics 64: 222-228

Robert Tisserand