Q: If my hair is just starting to thin, when should I have my first hair transplant? — T.O., Bayonne, NJ
A: It is best to wait until at least 25 before considering hair transplant surgery, although there are exceptions. The most important thing is to wait until you have hair loss that is a cosmetic problem. A hair transplant is a treatment for hair loss — it should not be used as a prevention. When hair loss is just starting, medical therapy is generally a better choice than surgery as it can both regrow hair and prevent future loss.
This issue is detailed in the publication Follicular Transplantation: Patient Evaluation and Surgical Planning.