How much mcg of biotin should a 15 year old take for hair loss. i've been losing a lot of hair & a dermatologist suggested to take biotin. ?

Does not matter: Taking biotin is not likely to help your hair loss. So take what you feel like but do not expect any useful results.

Suggest you see : your pediatrician, and have them Reglan (metoclopramide) hwork up your thyroid gland. You can take 2000 to 5000 µg a day of biotin no problem for hair thinning.However if you have excessive hair loss, you need to look at the cause of why this is happening, not just treat the symptoms. This could be related to stress, adrenals, or your thyroid gland.So talk to your doctor first before spending any money on biotin.

Depends: if the 15 yr old is over 100# in wt, then she could take an adult dose of 5000 mcg (5 mg) of Biotin) for treating hair. If she is on the small side, then 3500 mcg (3.5mg) per day. There is no FDA recommended dose for treating hair, as this is a vitamin and it's use in treating hair loss is off label. Nature's Bounty makes a "Hair, Skin, and Nails" tablet: 3 pills per day gives 5,000 mcg biotin