Biotin (Vitamin B7) Simply Explained

1. What Is Biotin (Vitamin B7)?

Biotin is a vitamin from the B-vitamin group and dissolves well in water. In the body, it helps as a coenzyme of several enzymes that process fats, carbohydrates, and proteins. As a dietary supplement, it is often associated with hair, skin, and nails. Medically, it is given to those who have too little biotin or an inherited disorder of biotin metabolism.

2. Where Is It Found, and What Is It Made From?

Biotin is found in many foods, for example in egg yolk, liver, nuts, oats, soy, and yeast. Intestinal bacteria also produce it. In foods, it is bound to protein and is cleaved in the intestine. In supplements, it is present in free form, as tablets, capsules, drops, or in mixtures with other substances.

3. What Does Biotin (Vitamin B7) Do? What Research Shows

Biotin Deficiency

Pregnant women who excreted increased amounts of a substance indicating mild biotin deficiency excreted less of it with biotin, and somewhat more with a sham treatment 15. In children with severe malnutrition, the activity of biotin-dependent enzymes increased with biotin, most strongly in those with initially low levels 18. Both studies are small and involve different groups.

Multiple Sclerosis

In multiple sclerosis, high-dose biotin was compared several times with a sham treatment. In an initial study in progressive MS, disability regressed in some patients, but in none with the sham treatment 7. The follow-up study SPI2 did not confirm this benefit 22. Another study showed no difference in vision loss due to MS 9. A summary of several studies found no confirmed advantage in disability, but more often a faster walking time 1.

Hair Loss

A review found three studies on biotin for hair loss. The most informative study with a comparison group showed no difference in hair growth 4. In another study, hair loss decreased from baseline with biotin from a plant extract, with or without silica 8. In hair loss, it remains open whether biotin helps mainly in cases of biotin deficiency.

Skin and Skin Inflammation

In acne patients taking isotretinoin, the skin dried out markedly without biotin, but not markedly with additional biotin; however, the groups were not compared directly 16. With biotin from a plant extract, skin elasticity increased compared with the baseline value 8. Both studies are small, in one the groups were not assigned at random, and neither reports a direct comparison of the groups.

Glucose and Lipid Metabolism

In adults with type 2 diabetes, total cholesterol decreased with biotin in a summary of several studies 2. Whether biotin alone lowers blood sugar is not yet confirmed 2. Two studies on mixtures of biotin and chromium picolinate showed better blood sugar and lipid levels, but these results apply to the mixture, not to biotin alone 614.

Brittle Nails

With biotin from a plant extract, nail roughness decreased from baseline in a study with a comparison group 8. A review lists biotin among substances that may improve the appearance, strength, and brittleness of nails 25. So far, there is only one study with a comparison group, and whether the participants had too little biotin is not clarified.

Other Investigations

In children with asthma, biotin in addition to usual treatment reduced two inflammatory markers in the blood more than a sham treatment; improved lung function was reported only for L-carnitine, a different substance 11. The other works are predominantly observational studies or investigate biotin in combination products. Controlled studies (with a comparison group) on clinical endpoints (study target) are still pending here.

4. How Was Biotin (Vitamin B7) Taken in the Studies?

In the studies, participants usually received biotin orally: as a dietary supplement, high-dose as a medication in multiple sclerosis, or in mixtures with other vitamins, minerals, or plant extracts. In hair loss, biotin was injected together with dexpanthenol 13 or applied in a hair product 12. The doses and forms are listed in the table.

5. Is Biotin (Vitamin B7) Safe? Side Effects in the Studies

Biotin was well tolerated in the studies: in multiple sclerosis, adverse effects with high-dose biotin did not occur more frequently than with a sham treatment 179. However, high-dose biotin can falsify laboratory tests: this happened in some of those treated, but in none with a sham treatment 1. Many positive results come from combination products and therefore do not apply to biotin alone.

All details with tables and sources: full expert page on Biotin (Vitamin B7)