Biotin does not have any known side effects, according to WebMD. Researchers have not determined a maximum safe dose of biotin due to the lack of adverse side effects.
As a supplement, biotin improves skin, nerve, digestive and cell health as well as improving metabolism. Biotin may also improve nail strength. Although insufficient, some research suggests that biotin may help diabetics boost blood sugar, states WebMD. The research indicates that insulin resistance and other diabetic symptoms may improve due to biotin. However, the research that has been done to date is not sufficient to make definitive claims for its use in treating diabetes or other conditions.
While biotin is safe to take as a supplement, it is also found naturally in food, and a deficiency in biotin is rare, says WebMD. Since biotin is most often found in foods containing protein, a diet with salmon, chicken, dairy and eggs is likely a sufficient source of biotin. It can also be found in wheat germ and whole-wheat bread.
Most often, a deficiency is found in pregnant women, but pregnant or breast-feeding women should consult a physician before taking a biotin supplement, states WebMD. Biotin may also interact with prescription drugs or reduce the effectiveness of them.