I know there are very few hair transplant doctors who perform follicular unit extraction (FUE) using body hairs. I have seen that some physicians use chest hairs. But is it also possible to do FUE with leg hairs?
In my opinion, don't even consider using body hair for hair transplantation unless you're scalp hair donor supply is used up (both via FUT and FUE). While some transplant surgeons have used body hair successfully in a select few patients, I've seen just as many (if not more) failed cases of body hair transplants.
Quite honestly, I have yet to see any real consistency with body hair transplantation (chest hair, leg hair, etc.) to consider it a mainstream hair restoration procedure. In my opinion, body hair is better used as "filler" hair, in extreme repair cases, and only when there's absolutely no scalp hair available for use.
Even then, the hair characteristics and their location will play a role in the success of the procedure. For instance, thin, fine body hair may sometimes too fragile to survive the trauma and doesn't usually make for any cosmetic improvement. Underarm hairs or hairs in other wet areas make for poor donor hair.
In scalp FUE, patients are typically not considered candidates if their scalp is soft or too malleable due to the added difficulty of extraction without damaging the follicles. In general, other areas of the body are much more impressionable than the scalp, making extraction more difficult. I'd imagine this may be one issue related to lower percentages of body hair growth yield.