Question: what is the best vitamin for your hair and nails?
Answer:  Best multi-tasker: Biotin. Nature's Bounty. ... 
 Best for hair loss (splurge): Nutrafol. Nutrafol. ... 
 Best for hair loss (budget): Viviscal. Viviscal. ... 
 Best for brittle, weak hair, skin, and nails: Cysteine. NOW supplements. ... 
 Best for dryness: Vitamin A.