Use of biotin in patients with hair loss.
The user's original question was "What scientific evidence is there for the use of biotin (vitamin H) in hair loss?"
The search in the usual databases has not identified clinical studies in which the role of isolated use of biotin (also called vitamin H, vitamin B7 and vitamin B8) in the treatment of hair loss in healthy adults is evaluated.
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Three randomized clinical trials (RCTs) of small sample size and short follow-up period have been located, among other methodological limitations, which, although they show satisfactory results associated with the use of oral supplements whose components include biotin, do not allow conclusions to be drawn regarding to the clinical effectiveness of this specific substance .
In a clinical practice guide (1) on the management of androgenetic alopecia (AAG) in men and women, published in 2011, it is only commented that certain vitamins, especially biotin and niacin, are attributed to hair growth promoting properties. and a positive influence on hair nutrition. At this point the guideline refers to a small RCT (2) that reported a significant improvement, compared to placebo treatment, of capillary loss in included males (with mild to moderate SAA) after 18-24 weeks of treatment with an oral supplement (twice a day) containing biotin and niacin, and also β-sitosterol and saw palmetto (improvement of 60%, in 6 of 10 patients, in the active treatment group, compared with improvement of 11%, in 1 of 9 patients, in the placebo treatment group).
In the summary of evidence of Uptodate on the AAG in women (3) it is indicated that the effectiveness of treatments such as mesotherapy, estrogens, and supplements, such as iron, biotin, ginseng, saw palmetto, tea green and caffeine, is not clear and refers to the aforementioned guide (1) .
In a systematic Cochrane review of interventions for female pattern baldness (4) , updated in its English version in 2016, two RCTs (5.6) were included in which the effectiveness of two nutritional supplements in which one of the compounds was biotin. However, the data from these studies were not used for the subsequent analysis of the results nor were conclusions drawn as to the effectiveness of these dietary supplements.
In the two RCTs (5,6) we proceeded in a similar way: a sample of subjects (55 subjects and 60 subjects, respectively) with hair loss of different etiologies were randomized to receive active treatment with the respective supplement or placebo during a first blinded phase of the study, which lasted 6 months. Then, during a second open phase, participants who had been taking the supplement in the blind phase continued with this treatment for a further 6 months, and participants who had been in the placebo group during the blinded phase went on to take the supplement during 12 more months All participants received, therefore, active treatment for 12 months. The objective evaluations at the capillary level that were carried out at the end of the blind phase of the study showed, in both studies, a significant positive effect of active treatment on hair growth. Subsequently, after the open phase of the study, the intake of the active preparation for 6 months, reported a further subjective improvement in hair growth. Exposure of patients previously treated with placebo to the active preparation for 12 months yielded similar results. The tolerability was good and no side effects were reported. In both cases it is concluded that the evaluated dietary preparations can provide an alternative to pharmacotherapy for the treatment of hair loss problems in people with AAG.
Finally, comment that there is also a lack of research in this respect in two relatively recient narrative reviews: in a 2014 narrative review of the treatments with supplements for the AAG (7) biotin is included and it is highlighted that to date there have been clinical trials that evaluate the efficacy of biotin in AAG, or in any other type of alopecia; and in another 2013 narrative review (8) we found that it has not been sufficiently demonstrated that additional biotin supplementation in patients with normal blood levels can improve hair loss, although there may be an effect on the structure of hair and nails.