Had major surgery & want to minimize hair loss if it happens. dr. said take 10 mcg biotin. is this right dose & does biotin really help with hair loss?

Doubt it: Biotin deficiency is rare, but can occur in persons with genetic mutations, on long-term antibiotics or anti-convulsants, or who eat a lot of raw egg whites. There is no good evidence that this easily available, over-the-counter supplement is the magic potion to grow hair or prevent hair loss. Biotin is safe to take at normal recommended doses (the Mayo Clinic website recommends 30-100 mcg a day).