Seeing more strands of hair fall out than usual can be worrying. But one health expert says thinning hair could sometimes point to a bigger issue other than simply 'getting old'. Dr Eric Berg , who has more than 2.3 million followers and over 30 million likes on TikTok, as well as 14 million YouTube subscribers, brought attention to the issue in a viral video . He told viewers: “Thinning of the hair could be a biotin deficiency.” Biotin, also known as vitamin B7, is part of the B-vitamin family