Apparently biotin only works for some nails. (Photo by nothing)
It's now been a month since I started taking 5 mg of biotin daily to see whether it would have an effect on hair and nail growth. Unfortunately, it didn't.
I'm sure I will continue to read positive claims about taking biotin supplements by some people, but I suspect that either these people have actually been deficient in biotin (which is rare but not impossible) before the supplementation, are attributing the benefits of something else (another supplement, for example) to biotin, or are simply imagining the results.
The last option is probably very common and an easy mistake to make without properly measuring things like nail growth speed, hair shaft thickness etc. The only tool I had was my subjective evaluation, so this was hardly a controlled clinical study. However, people are more likely to see results when there are none than the other way around, which means that when I don't even see any subjective results, there probably aren't objective results either.
Thankfully, biotin supplements are pretty cheap, so you may want to try them for yourself, but before I see some actual studies on biotin's effectiveness, I won't be spending any more money on it.
For more information on hair growth, see these posts:
Mixture of 5-Aminolevulinic Acid and Iron Increases Hair Growth in Mice
3 Quick Ways to Find Out Whether Your Hair Growth Product is Working
Green Tea Extract Grows Hair in Vitro, May Work in Vivo
Vitamin E Tocotrienols May Grow Hair in Humans