As reported in The Huffington Post, one dermatologist believes that biotin might not actually be beneficial for hair and nails — on the contrary, he believes that it may actually do more harm than good. Dr. Richard Scher, a derm that specializes in nail care, argues that hair loss and nail weakness may have many possible causes. While biotin may help symptoms if biotin deficiency is present, it is actually possible to overdose on biotin, says the doc. Why is that bad? Well, symptoms of overdose can include scary signs such as skin rashes and high blood sugar levels. Yikes.
The bottom line: Don't start popping supplements without speaking to your doctor first — even if they're harmless-seeming supplements that promise snazzy beauty benefits. Brittle nails or hair loss can be signs of major health issues, so if you notice these symptoms, it's worth seeing a doc to get to the (real) heart of the matter. (Huffington Post)