Q: Is it true that smoking is bad for a hair transplant and why? P.P. – N.Y., N.Y.

A: Smoking causes constriction of blood vessels and decreased blood flow to the scalp, predominantly due to its nicotine content. Also, carbon monoxide in smoke decreases the oxygen carrying capacity of the blood.

These factors both contribute to poor wound healing after a hair transplant and can increase the chance of a wound infection and scarring. Smoking may also contribute to poor hair growth.

The harmful effects of smoking wear off slowly after one stops. In particular, chronic smokers are at risk of poor healing after smoking has stopped for weeks or even months.

Although it is not known exactly how long one should avoid smoking before and after a hair transplant, a common recommendation is to abstain from 1 week prior to surgery to 2 weeks after the hair restoration procedure.