There many websites selling biotin suplements claiming that they will make hair grow stronger and faster. Here are two examples:
Bio-info Hair Growth
Biotin deficency is shown to cause some problems including hair loss.
But a deficiency must be extremely rare: recommended doses vary up to 25mcg, which is easily gotten from an egg white. Supplements are generally sold with 3000-5000mcg per capsule.
Do biotin supplements increase hair growth and strength?