Is there evidence behind biotin and hair growth? (Photo by Martin Neuhof)
Long-time readers of the blog may remember that one of the earliest experiments I did was with biotin, also known as vitamin B7. The purpose was to see whether taking a biotin supplement would affect nail and hair strength.
I wrote back then that although a lot of people seemed to believe biotin is good for hair and nails, there were no studies showing it really did anything except in rare cases when the subject was biotin deficient. After two weeks, I posted a quick update. When I'd been taking 5 mg for a month, I concluded the experiment. As you might expect, I didn't see any results.
I've since learned that one month is way too short for any kind of results when it comes to hair growth experiments. In most cases, six months would be the minimum, otherwise you're just wasting money without really learning anything new.
A pubmed search on biotin and hair growth still doesn't come up with any interesting studies. The only thing biotin seems to be proven to do is help with uncombable hair syndrome (link):
We report a family affected to the fourth generation by uncombable hair syndrome. This syndrome is characterized by unruly, dry, blond hair with a tangled appearance. The family pedigree strongly supports the hypothesis of autosomal dominant inheritance; some members of the family had, apart from uncombable hair, minor signs of atopy and ectodermal dysplasia, such as abnormalities of the nails. The diagnosis was confirmed by means of extensive scanning electron microscopy. A trial with oral biotin 5 mg/day was started on two young patients with excellent results as regards the hair appearance, although scanning electron microscopy did not show structural changes in the hair. After a 2-year-period of follow-up, hair normality was maintained without biotin, while nail fragility still required biotin supplementation for control.
In this study, 5 mg biotin was taken daily. Even much smaller doses seem to be helpful for uncombable hair syndrome, however (link):
Three children are reported with uncombable hair syndrome, consisting of slow-growing, straw-colored scalp hair that could not be combed flat. The hairs appeared normal on light microscopy but on scanning electron microscopy were triangular in cross section, with canal-like longitudinal depressions. Oral biotin, 0.3 mg three times a day, produced significant improvement after 4 months in one patient, with increased growth rate and with strength and combability of the hair, although the triangular shape remained. The other two patients were unique in having associated ectodermal dysplasia. Their hair slowly improved in appearance and combability over 5 years without biotin therapy.
These studies confirm the fact that biotin does play a part in hair growth, and that it's possible to affect even the growth rate through biotin supplementation. Although the cause of uncombable hair syndrome is unknown, a biotin deficiency (perhaps due to genetic reasons) may play a part. On the other hand, the syndrome often improves by itself with age.
Studies like this do not really warrant supplementing with biotin if you're suffering from androgenic alopecia or just want to make your hair grow thicker and faster. And yet a lot of people seem to believe biotin will do the trick. They keep saying there's "a lot of evidence" for biotin and hair growth, but the references are missing. The actual studies are always about biotin deficiencies or like the ones I quoted above.
However, a while ago I came across one study from 1992 that actually looked at the effect of biotin supplements on hair loss. It's no wonder I didn't find it earlier, since it's not indexed in pubmed. Nor do I have access to the full paper, but here's the abstract:
An examination of the effect of biotin on alopecia and hair quality.
The effect of a daily oral dose of 2,5 mg biotin was studied in 93 patients with the symptoms hair-loss (mostly androgenetic alopecia) and reduced hair quality. The mean duration of treatment was 7,9 +/- 2,8 months. An obvious improvement of hair-loss was reported in 64%, and a slight improvement in 9%. Hair quality was clearly improved in 70% and slightly in 12%. Brittle finger nails as an additional complaint were improved in 80%. If alopecia, decreased hair quality and brittle finger nails occurred in combination, improvement was observed frequently collectively. The study allows - as already shown in a previous investigation concerning brittle finger nails - to suggest biotin as an effective and well tolerated therapy in cases of alopecia and decreased hair quality.
The majority of subjects had improvements in hair loss and hair quality from taking 2.5 mg biotin daily. Sounds good, right? Makes you wonder why nobody has attempted to repeat the experiment if the results are real. Another thing that strikes me as odd is the duration of the experiment. Why a mean duration of 7.9 months with standard deviation? Weren't all the subjects taking biotin for the same duration? Did they just quit whenever they felt like it? That just sounds like bad study design, which makes me somewhat skeptical of the results.
Still, it's intriguing enough to make me add biotin back on the supplement menu for the time being. Although a "it can't hurt and might help" mentality may be dangerous in some cases, I'm unaware of any negative side effects from taking 5 mg biotin daily. This time I'm aiming for at least six months instead of just one.
For more information on hair growth, see these posts:
Soy Isoflavones and Chili Pepper for Hair Growth – Experiment Update
Emu Oil vs. Hair Again® Topical Gel: Hair Growth Battle Conclusion
Do Flax Lignans Reduce Hair Loss from MPB?
2% Nizoral Shampoo Increases Hair Growth More than 2% Minoxidil