Q: Does a man’s height and weight affect the dose of finasteride or Propecia he should take? i.e. will a 6’4″ man need a higher dose than a 5’7″ man. — T.B., Rye Brook, NY

A: The dose of finasteride is the same (i.e. 1mg) regardless of a person’s height or weight. The reason is that one needs only 0.5mg a day for it to be effective, so there is much leeway built into the dose (but the rate of non-responders is slightly higher at the 0.5mg/day dose). That said, after 5 years or so, finasteride seems to be less effective and doctors often increase the dose a bit. The next step-up is generally to take 1/3 of a 5mg pill each day. Keep in mind that the dosing we are speaking about is for hair loss (androgenetic alopecia). When finasteride is used for prostate enlargement, the dose is 5mg a day.