Q: I’m concerned that finasteride might result in unwanted body hair on the arms, back, etc. Is there any truth to this? My thinking is that since finasteride blocks the enzyme 5 alpha-reductase which converts testosterone to its more active form, DHT (dihydrotestosterone), is it possible that it might actually have some effectiveness in ameliorating unwanted hair?

A: Yes, finasteride does have some ability to decrease body hair, since growth of body hair is stimulated by DHT. However, the effects of finasteride are mild and not observed by everyone, so if you have unwanted body hair you will probably need some other means to remove it such as waxing, laser hair removal or electrolysis. The important thing is that finasteride doesn’t increase body hair.

Q: Is it recommended to wait for 1 year after starting Propecia, when the effect of the medication kicks in and improves density of donor area, and then perform the surgery?

A: Propecia will not affect the donor area, as this area is generally not impacted by the miniaturizing (thinning) effects of DHT –- the hormone that Propecia blocks. The purpose of waiting the year is to possibly regrow hair in the recipient area. If regrowth is significant, a hair transplant may not be necessary. If a person’s hair loss is extensive and there is little chance that Propecia will grow a significant amount of hair back to give a satisfactory improvement, then waiting the year is unnecessary.

Q: What happens to hair diameter when you age?

A: From infancy to puberty, hair gets progressively thicker. From adulthood to old age the hair becomes thinner again and this is exacerbated by the effects of DTH in susceptible persons. The later process is called androgenetic alopecia (common baldness) and is characterized by miniaturization – the progressive decrease in hair diameter and lengths as a result of DHT.

However, even without the effects of DHT, hair gradually thins over time in many people.

Q: I am currently 28. I have been taking Propecia for 6 years and recently began to grow sparse chest hair for the first time in my life. Is the Propecia causing these effects?

A: DHT causes male pattern baldness and stimulates the growth of body hair. The use of Finasteride, a DHT blocker, will permit scalp hair to grown and inhibit the growth of body hair, not stimulate it.

However, the effects on body hair are quite small, so your natural tendency to grow chest hair over time is probably not being blocked by the treatment.

Q: I know that Propecia works in only about half of patients. Are younger people more likely to be helped by this medication?

A: The main studies by Merck looked at men between the ages of 18 and 41. The five year data (which, in my view, is most important) showed that 48% of men had an increase in hair growth and 42% had no change over baseline. Thus a full 90% held on to their hair or had more over a 5-year period. This compares very favorably to the placebo group where 75% lost hair over the 5-year period.