Do Doctors Offer a Hair Transplant Guarantee?

What happens if the hair doesnt grow after a transplant? Do doctors offer a guarantee of some sort? I know each doctor or clinic would have their own policy, but I wasn’t sure if there was some sort of standard thing most doctors offer.

Guarantees in medicine are illegal in most of the 50 states. Imagine guaranteeing that your cancer will be cured by one particular doctor as a marketing gimmick, then you die. What is the recourse?

There are practical guarantees of replacing that did not grow at no cost to you and this is common in the industry without violating any laws.