I am considering an eyebrow transplant due to having lost a good portion of my eyebrows as I have aged. (I am in my mid-40s). Can you discuss the relative merits between using leg hair and scalp hair for eyebrow transplant procedures? I have heard some doctors prefer leg hair for this procedure.
Leg hairs do look similar to eyebrow hairs and can grow to about the same length, so it may be an option. The major problem with leg hair is the length of the telogen portion of the hair growth cycle. The telogen component (the period where the hairs are not growing above the skin and are in a rest period below the skin) is about 60-70% of the total cycle. That means that for every ten hairs that are transplanted, only about 3 will be growing above the skin to see at any one time. With scalp hair, the telogen component of the hair growth cycle runs about 3 months and the growth phase runs about 3 years. Better value!
In general, we have traditionally transplanted scalp hair to eyebrow, because we have the most experience with scalp hair and know how it behaves (its growth cycle is predictable).