Will my hair transplant be successful if I smoked pre-op?

It is best to contact your doctor about post operative care and instructions since each doctor has a different regimen.  Most doctors would recommend that you do not smoke.

Nicotine causes vasoconstriction. Vasocontriction can compromise blood flow to the grafts ultimately altering graft take. I typically recommend smoking cessation (including all forms of nicotine replacement) for 6 weeks prior to surgery.As always, discuss your concerns with your board certified plastic surgeon (ABPS) with experience in hair restoration.

Of course, everyone knows that smoking is unhealthy & can affect many areas & organs of the human body. Smoking before a hair transplant should be discontinued at least a few days if possible, however it worries me a lot more for a patient to smoke after the procedure. Nicotine is a vasoconstrictor (stimulates constriction of the smooth muscles within the vessel wall) which impedes blood flow to the recently transplanted follicles. This is very important after the procedure because the follicles are suffering from what we call anoxic injury. This injury results from lack of oxygen while the follicles are outside the blood supply of the scalp. Anything that diminishes blood flow after the procedure is to be avoided & could result in a percentage of grafts failing to survive. 

Nicotine in any form (smoking, gum, patch, vapor etc.) causes blood vessels to constrict and limits circulation.  This can have an adverse effect on healing of wounds, incisions and grafts.  Although it has never been shown to be a major issue in hair transplant surgery, it is prudent to avoid nicotine in any form for at least a week before and two weeks after surgery, ideally longer.

The less you smoke the better the outcome of your hair transplant will be.  Keep away from cigarettes if you can