although biotin does play a role in amino acid metabolism there are no studies (that i can find) that show taking biotin decreases lactic acid production. if someone is deficient in biotin it could limit performance or muscle formation but that is unlikely. if you are getting enough through diet you probably don't need to supplement. for more on lactic acid and biotin see these articles: exercise and lactic acidosis biotin supplement guide
does biotin help reduce lactic acid build up. i started kick boxing and doing a lot more activity in an effort to get back into shape. i was told biotin would help break down the lactic acid build up in my muscles