What is Biotin?
Biotin is a water-soluble vitamin that is generally classified as a B-complex vitamin. Biotin is required at the active site of five enzymes in the human body, collectively known as ‘carboxylases’. These carboxylases play a variety of roles in the body including, fatty acid and glucose synthesis, branched-chain amino acid metabolism, cholesterol metabolism and fatty acid metabolism.
Where Does Biotin Come From?
Biotin is found in many foods, but generally in lower amounts than other water-soluble vitamins. Egg yolk, liver, and yeast are rich sources of biotin3.
Supplementation with biotin has been shown to lower plasma triglycerides and very low density lipoprotein in both type 2 diabetic subjects and non-diabetic subjects4. Similar, but more pronounced changes in triglycerides and cholesterol where found when biotin (2-5mg) was combined with chromium picolinate (600mcg) in high doses in type 2 diabetics5. Three other studies have produced similar findings6-8, including favourable changes in fasting blood glucose and HbA(1c)suggesting a synergistic mechanism between chromium picolinate and biotin. Biotin supplements might also be helpful in strengthening brittle fingernails with two trials in woman showing subjective evidence of clinical improvement9, 10.
Negative Side Effects of Biotin
A search of the scientific literature suggests that there are no significant negative side-effects from oral consumption of biotin in normal doses.
Biotin Recommended Dosages & Timing
Biotin is typically taken in amounts between 100mcg and 1mg. However, as highlighted above, a number of studies have used between 2 and 5mg of biotin in combination with chromium picolinate to improve glucose control in type 2 diabetics. Even in these amounts, biotin is thought to have no toxicity. Individuals on long-term anticonvulsant (anti-seizure) therapy reportedly have reduced blood levels of biotin11, 12and therefore may be candidates for biotin supplementation. No specific guidelines exist concerning the timing of biotin supplementation.
Biotin typically features as part of ‘b-complex vitamin’ products or multivitamins.
As indicated above, biotin is most commonly combined with other b-complex vitamins and/or minerals.
Biotin is not known to be toxic. Oral biotin supplementation has been well-tolerated in doses up to 200,000 mcg/day in people with hereditary disorders of biotin metabolism1. In people without disorders of biotin metabolism, doses of up to 5,000 mcg/day for two years were not associated with adverse effects2.
1. Food and Nutrition Board, Institute of Medicine. Biotin. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press; 1998:374-389.
2. Koutsikos D, Agroyannis B, Tzanatos-Exarchou H. Biotin for diabetic peripheral neuropathy. Biomed Pharmacother. 1990;44(10):511-514.
3. Staggs CG, et al Determination of the biotin content of select foods using accurate and sensitive HPLC/avidin binding. J Food Compost Anal. 2004;17(6):767-776.
4. Revilla-Monsalve C, Zendejas-Ruiz I, Islas-Andrade S, et al. Biotin supplementation reduces plasma triacylglycerol and VLDL in type 2 diabetic patients and in nondiabetic subjects with hypertriglyceridemia. Biomed Pharmacother. 2006;60(4):182-185.
5. Geohas J, et al. Chromium picolinate and biotin combination reduces atherogenic index of plasma in patients with type 2 diabetes mellitus: a placebo-controlled, double-blinded, randomized clinical trial. Am J Med Sci. 2007;333(3):145-53.
6. Singer GM & Geohas J. The effect of chromium picolinate and biotin supplementation on glycemic control in poorly controlled patients with type 2 diabetes mellitus: a placebo-controlled, double-blinded, randomized trial. Diabetes Technol Ther. 2006;8(6):636-643.
7. Albarracin C, et al. Combination of chromium and biotin improves coronary risk factors in hypercholesterolemic type 2 diabetes mellitus: a placebo-controlled, double-blind randomized clinical trial. J Cardiometab Syndr. 2007;2(2):91-97.
8. Albarracin CA, et al. Chromium picolinate and biotin combination improves glucose metabolism in treated, uncontrolled overweight to obese patients with type 2 diabetes. Diabetes Metab Res Rev. 2008;24(1):41-51.
9. Romero-Navarro G, Cabrera-Valladares G, German MS, et al. Biotin regulation of pancreatic glucokinase and insulin in primary cultured rat islets and in biotin-deficient rats. Endocrinology. 1999;140(10):4595-4600.
10. Floersheim GL. [Treatment of brittle fingernails with biotin]. Z Hautkr. 1989;64(1):41-48.
11. Camporeale G, Zempleni J. Biotin. In: Bowman BA, Russell RM, eds. Present Knowledge in Nutrition. 9th ed. Volume 1. Washington, D.C.: ILSI Press; 2006:314-326.
12. Schulpis KH, Karikas GA, Tjamouranis J, Regoutas S, Tsakiris S. Low serum biotinidase activity in children with valproic acid monotherapy. Epilepsia. 2001;42(10):1359-1362.