Later On

A blog written for those whose interests more or less match mine.

Lavender & tea-tree oils unsafe for boys

with 18 comments

UPDATE: From emails and discussions, I realize that the following story is easily misread. The problem exists only for young boys, not adults. Puberty unleashes a tsunami of hormones that makes the tiny contributions from lavender oil and tea tree oil in cosmetic products negligible. And, indeed, I would guess that the vagaries of individual differences would produce different effects in different young boys. But certainly there’s nothing in the following to suggest that adolescents or adults are at any risk whatsoever from these cosmetic products.

UPDATE 2: See comment below by Jennifer, which references some criticisms of this study. Link to come.

From Science News, issue of 1 July 2006 (behind subscription wall):

Two ingredients common in many hair- and skin-care products have been linked to abnormal development of breasts in boys. Lavender oil and tea tree oil contain compounds that act like female sex hormones and interfere with male hormones, researchers have determined.

Enlarged male breasts, or gynecomastia, result from an imbalance between the activity of estrogens, which stimulate breast growth, and estrogen-inhibiting androgens. The condition is extremely rare before puberty, says Denver-area pediatric endocrinologist Clifford Bloch.

Nevertheless, since the mid-1990s, Bloch has treated gynecomastia in a series of boys age 10 or younger. Most had normal ratios of sex hormones in their blood, indicating that theirs wasn’t a problem of hormone production.

From the youngsters and their parents, Bloch learned that at least five boys had been using a shampoo, hair gel, soap, or another topical product that listed lavender oil among its ingredients. One of the products also contained tea tree oil. “A couple of patients were putting pure lavender oil on their skin,” he says.

Bloch recommended that the boys stop using lavender-containing products. When they followed his advice, gynecomastia disappeared within a few months.

To verify his hunch that the plant oils were hormonally active, Bloch contacted Derek Henley and Kenneth Korach of the National Institute of Environmental Health Sciences in Research Triangle Park, N.C. In their lab, the two investigators exposed human-breast cells to lavender oil and, separately, to tea tree oil. They found that each oil turned on estrogen-regulated genes and inhibited an androgen-regulated gene.

“These oils possess both estrogenic and anti-androgenic properties,” Henley reported at the Endocrine Society meeting in Boston this week. He adds that the finding is the first to implicate “essential oils” from plants in gynecomastia.

Young boys should avoid the oils, Bloch advises. Many personal-care products contain them. Other plant products act like estrogens in the body.

Pediatric endocrinologist Edward Reiter of Tufts University School of Medicine in Springfield, Mass., applauds Bloch for his “impressive, Sherlock Holmes” performance in unearthing what the boys had in common. While similar patients probably trickle in to other endocrinology clinics, he says, the cause of their enlarged breasts could escape diagnosis because doctors don’t make the connection to personal-care products.

“If I had seen [just] one of those kids, I’m sure I would have missed it,” he says.

The rapid reversal of gynecomastia that Bloch accomplished is a rare achievement in medicine, comments Ken Ong, a pediatric endocrinologist at the Medical Research Council in Cambridge, England. As such, it strongly suggested a link between the products and the boys’ problem.

The plant essences presumably have similar potential effects in young girls, Reiter says. Studies show a recent rise of early breast development in girls. Prepubertal children have low sex hormone concentrations, so relatively small amounts of hormone-mimicking compounds might upset their physiologic balance at that age, says Reiter.

Written by Leisureguy

11 July 2006 at 11:38 am

Posted in Health, Science

18 Responses

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  1. Gynecomestia is perhaps the most annoying health disorder in the males. Science News has stated right that gynecomestia is the development of abnormally large breasts on men. Gynecomestia results from the imbalance between the activity of estrogens, which stimulate breast growth, and estrogen-inhibiting androgens. Though it is an annoying disease it is curable.



    21 July 2006 at 3:44 am

  2. My 9 year old son has a lump under his right nipple. I googled boy breast lumps and came upon this article regarding use of Tea Tree Oil.

    Well, my son has had terrible cradle cap since he was born. A good friend of mine is a hairdresser and suggested I get him a shampoo that contains Tea Tree Oil. My son used this shampoo for a couple of months but hasn’t used it in about six weeks. He just noticed the lump about a week ago. He says it’s a little uncomfortable when he lays on his belly.

    Do you feel it’s possible that the lump could have appeared about 6 weeks after stopping the use of the Tea Tree oil shampoo.

    A side note is that I am currently 43 and had breast cancer when I was 39. I have since tested positive for the BRCA2 gene.

    Someone, please respond!!!!

    Thank you.


    Laurie Conway

    21 July 2006 at 7:03 pm

  3. Unfortunately, I’m not qualified to respond, but I do suggest that you print out the article and take it with you to an endocrinologist—or, perhaps, first to your primary care physician.

    Good luck.



    21 July 2006 at 7:49 pm

  4. I read this article with interest. My 15 year old grandson has this problem. Because of teasing, his self esteem is low, he wears 3 tee shirts all the time, won’t go swimming, doesn’t stand up straight, and it wears on his mind all the time. He has used the personal care products mentioned. Of course since learning of this, all those products are gone. The article says that the problem then goes away quite quickly. Anyone had the experience of this reversal? Anything else that can be done, beside not using the products?
    Teasing by his peers has made his life miserable.


    Patricia Subbayya

    25 July 2006 at 8:38 am

  5. Glad the article is useful. So far as anything else that can be done, I would recommend that you check with his primary care physician and/or an endocrinologist. I suggest you take with you the printed article, in case the study is news to them.



    25 July 2006 at 8:45 am

  6. Could this be true for rosemary or sage? The plants rosemary and sage are similar to lavender. Just wondering.



    29 July 2006 at 10:59 pm

  7. I have no idea. The oils from those plants were not included in the study, so far as I can tell.



    30 July 2006 at 12:46 am

  8. I stumbled into this thread whilst researching on the estrogenic properties of Maleleuca Tea Tree. Let me also state that I am not “advertising” or receiving any monetary benefits from the sources I am about to mention. I just wanna share this with you, and hope it would help you.

    Mine is a cyst problem, but the cause of it could be the same cause for breasts in young boys. Overdose of estrogen.

    2 months ago, I was diagnosed with an ovarian cyst (my mum has 1 too) and my gynae recommended a surgery to remove it. I found out through subsequent research, of the late Dr John M Lee breakthrough research on estrogen being the factor responsible for breast cancer, fibroid cysts, ovarian cysts, PMS problems, hot flashes, etc etc… the list goes on. I subsequently found a resident doctor in US (I am in Singapore) who administers this theory with a natural progesterone oil. One of his guidelines was to avoid estrogen from the environment, and particularly to watch out for what goes on the skin. Sage and rosemary are amongst the herbs that were listed as being estrogenic, and should be avoided. There are other herbs that has hormonal effects, too.

    I cut down ruthlessly on estrogen (and whilst I am looking for a new laundry detergent, I haven’t even started on the oil), and the results have been very good. I sleep better, my back aches are gone, my acne improved.

    I was researching on Maleleuca products, and found this site. Thanks for pointing out the effect of Tea tree oil on young boys. I am currMy hunch is that it may be estrogenic, and hence I would not go for the Maleleuca laundry detergent I was eyeing on.

    You might wanna check out Dr John Lee’s book “What Your Doctor May Not Tell You About Menopause”. There are other books in the series “What Your Doctor May Not Tell You…”

    Hope this helps. If you wanna find out more, you can email me. Due to lack of time, I doubt I will revisit this site to follow up on the discussion, but I certainly hope you find a solution soon.



    30 July 2006 at 8:57 pm

  9. My son had this problem years ago, we did not use these EO in any of our products. Our solution to the problem was to have surgery at age 17 to have them removed. He is very happy and quite pleased with the turn out.

    Perhaps you can look into that when the age is right.



    1 February 2007 at 5:00 pm

  10. I recently read that the studies performed by Bloch were extremely unscientific (all three boys were from the same clinic and were not tested for environmental factors like parabens, phosphates or pesticides), and that tea tree oil wasn’t even in any of the products on a stand alone basis, only lavender oil was. A lot of assumptions were made on the diagnosis of 3 boys and one invitro study that indicated the oils mimicked estrogen. No further research has been done, and no further “epidemic’ has been mentioned. Tea tree oil has been used for thousands of years by the Aborigines and they aren’t running around with breasted young men.



    25 July 2007 at 8:51 am

  11. Good addition, Jennifer. I’ll update the post. Do you have a link for the criticisms of Bloch’s study? That would be useful.



    25 July 2007 at 9:11 am

  12. I have used these natural oil products for decades, so my now 20 year old daughter has been exposed to these products again and again. I never used anything other than tea tree oil for cuts and abrasions, ear infections, lice prevention and treatment, the list goes on and on. She had no signs of early breast development at all, and neither did dozens of children I have known whose parents used them, and that is a lot of people these days.

    You will notice that at the end of the “source” article above, there IS mention of the possibility of this phenomenon happening to little girls as well. Strange that the treating physician has not had any little female patients.

    There are thousands, if not hundreds of thousands of people, who have safely used these products over and over. Lavender oil especially is not new, it has been successfully used by women for hundreds of years in England and Europe. When I was a girl growing up in the 1960’s old ladies frequently smelled of lavender oil, and it is hard to imaging that they did not use it for all sorts of things, as a preservative in clothes closets to a headache reliever, on pillows to calm and induce relaxation and sleep, you name it.

    What is much more commonly used these days, and which was unknown 50 years ago, is the incredibly widespread use of the contraceptive pill, and also the chemical herbicide glyphosate (aka Roundup). Both contain large amounts of synthetic estrogen compounds, and are being discharged into waterways at an unprecedented rate, and being taken up by biological organisms, including humans, every day. And what about the growth hormones given to livestock and then eaten by humans etc.?

    If boys (and these articles cite no female patients) are being affected in this way (and I assume that we are not simply talking about obese children here, who are known to sufferf from enlarged breast tissue for obvious reasons, as do adult obese males), then perhaps people should familiarise themselves with the very modern condition aka “intersex” which is afflicting male babies at an alarming and ever-increasing rate (about 1:10,000). Some male babies are so affected by estrogen hormone compounds in utero that they fail to fully develop male reproductive organs, and sadly, many of these boy children have been subjected to sex change operations in the UK. Some are now adults and campaign against the operations, which are unethical to say the least, seeing as the children affected are under age, and therefore cannot have been sufficiently informed to consent, but have to live with the legacy of being in sexual limbo for the rest of their lives. It’s a scandal.

    People should be looking to synthetic chemical pollution for the answer to these problems, and lobbying politicians to regulate more stringently the use of synthetic chemicals, especially these notorious hormones and endocrine disruptors, before males die out completely.. Even male fish are being affected, ie increasingly exhibiting female sex characteristics and failing to breed, and scientists are testing the water they live in only to find …youi guessed it…synthetic estrogen compounds in the water.

    It takes only THREE parts per million to change the delicate balance of the natural order. it isn’t rocket science. It’s mad science. And it is wreaking havoc from one end of the planet to the other. Somehow, it must be stopped.


    Deb Guildner

    7 September 2007 at 4:40 pm

  13. Jennifer,

    It’s not really relevant that Tea Tree Oil wasn’t a stand alone EO in the products. The case led them to test it and it was confirmed it does in fact mimick Estrogen.

    I used a shampoo that contained Tea Tree Oil in it. I started in Sept ’04 and by Nov I had noticed what I thought was fat developing on my chest. This continued as I also continued to use the new shampoo for almost 3 years..DAILY. Well I came across this study and thought ‘wow…what a coindidence’. it’s been almost 8 weeks since stopping and I’ve since lost 9 lbs (no excercise). I wasn’t overweight to begin (5’10 193lbs…now weigh 184 lbs). My chest fat is definately going down but not where it was previous to the shampoo. I’m confident it’ll continue to decrease as time goes on. I did take the stuff for close to 3 years…w/out missing a day and being a clean freak I shampoo’d my hair up to 3x daily.



    Jack Evans

    10 September 2007 at 11:58 am


    I have been using tea tree skincare products for my spots on my face for around 2-3 years and recently over the last year iv been getting allot of fat chest (MAN BOOBS) is this the cause????

    I do exercise and am not fat ……..

    If this is the case and i stop using them, how long will it take for them to go down and disappper??????



    10 April 2008 at 4:03 pm

  15. Stop using the tea tree products and the condition (if that’s the cause) will reverse itself. I don’t know how long the reversal will take.



    10 April 2008 at 4:08 pm

  16. Okay I have a 14 yr. old son who went to go live with his grandma for about 6 months he just came home a couple of days ago and to our shock he had developed breasts with in the last 2 months, I think instead of worrying about the essential oils we need to worry more about the high amounts of hormones in red meat and milk(unless organic), especially the BGH hormones which cause premature boobs in little girls and premature menstration so why would it not do this to little boys. I feed my kids a very low amount of those things and I’m convinced that that is the cause, I went to the health food store and bought him a vitamin that helps ladys mostly who are going thru menapause so it helps slow down estrogen and I also put him on Korean Ginseng to help with the male hormones.

    I also have put Tea tree oil in my other sons hair because of cradle cap he is 11 yrs old and have had no problems with his breasts growing it only got rid of the cradle cap.



    19 July 2008 at 4:53 pm

  17. Liz I wouldnt use ginseng for male hormones as this is a known phytoestrogen.

    In fact mistakes like that are frequent, this whole thing gets rather confusing. In retrospect it sounds really dumb but in the hope of reducing my exposure to estrogen-like chemicals i bought natural, organic shampoo and body wash that get their smell from .. lavender, sage and rosemary. 40$ going straight in the garbage.



    18 July 2009 at 12:11 pm

  18. Real scientific studies didn’t find anything. Don’t believe all you read. Remember big pharma doesn’t want you to use natural stuff they can’t patent.


    Sandra Cruz-Pol

    5 December 2015 at 4:49 pm

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