A: A study of published research suggests that there is currently insufficient evidence that biotin supplementation is beneficial for humans with type 2 diabetes (T2DM) (see below). Where research has suggested a benefit of biotin supplementation in humans with T2DM,
Biotin deficiency in humans is very rare, and it is thought that average daily intakes of biotin from the diet exceed likely requirements. It isn't currently known if humans are able to absorb and use biotin produced by gut bacteria.
See Biotin - Linus Pauling Institute.
The Laminitis Site is not aware of any research in horses that has looked at the effect of supplemental biotin on blood insulin or glucose levels. However, some points to consider:
The US National Library of Medicine's page on biotin suggests that there is insufficient evidence to rate the effectiveness (of biotin) for diabetes (in humans):
"Diabetes. Biotin alone doesn’t seem to affect blood sugar levels in people with type 2 diabetes. However, there is some evidence that a combination of biotin and chromium (Diachrome, Nutrition 21) might lower blood sugar in people with diabetes, whose diabetes is poorly controlled by prescription medicines. Other early evidence shows that the same combination reduces ratios of total cholesterol levels to “good” high-density lipoprotein (HDL) cholesterol, “bad” low-density lipoprotein (LDL) cholesterol to HDL cholesterol, and non-HDL to HDL cholesterol in people with type 2 diabetes."
In humans, this 1993 paper suggested that serum biotin was low in people with type 2 diabetes and that biotin supplementation reduced hyperglycaemia:
Masaru MAEBASHI, Yoshio MAKINO, Yuji FURUKAWA, Kosaku OHINATA, Shuichi KIMURA, Takao SATO
Therapeutic Evaluation of the Effect of Biotin on Hyperglycemia in Patients with Non-Insulin Dependent Diabetes Mellitus
Journal of Clinical Biochemistry and Nutrition Vol. 14 (1993) No. 3 P 21
and this 2007 paper found that blood glucose levels lowered in obese patients with T2DM given a combination of chromium and biotin:
Am J Med Sci. 2007 Mar;333(3):145-53.
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.
Geohas J1, Daly A, Juturu V, Finch M, Komorowski JR.
However, chromium alone has been suggested to lower hyperglycaemia in diabetic patients, so the positive effects suggested by the above paper by Geohas et al. may not have been due to the biotin:
J Clin Pharm Ther. 2014 Jun;39(3):292-306. doi: 10.1111/jcpt.12147
Systematic review and meta-analysis of the efficacy and safety of chromium supplementation in diabetes
Suksomboon N1, Poolsup N, Yuwanakorn A
and this paper from 2004 found no effect on blood glucose or insulin levels after 28 days of biotin supplementation (in fact, insignificant increases in blood glucose and insulin were seen in the biotin supplemented diabetic and non-diabetic people compared to the placebo groups - see Table 2)
Am J Clin Nutr. 2004 Feb;79(2):238-43
Effects of biotin on pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA carboxylase, and markers for glucose and lipid homeostasis in type 2 diabetic patients and nondiabetic subjects
Báez-Saldaña A, Zendejas-Ruiz I, Revilla-Monsalve C, Islas-Andrade S, Cárdenas A, Rojas-Ochoa A, Vilches A, Fernandez-Mejia C