Will Rogaine Be Sufficient After a Hair Transplant?

Nothing can beat the genes you inherited. Rogaine will lose.  It may be in your interest to see a doctor for a proper diagnosis and treatment options.  When a doctor examines your hair loss pattern, he/she can give you some idea of what to expect and ways to address your hair loss with medications and even surgery.

Minoxidil (Rogaine) and Finasteride (propecia) work via different mechanisms; the two work better together than either on alone.  Most people feel that Finasteride is more effective than Minoxidil if you are going to chose only one.  Both medications serve to slow the progression of your hair loss but will not stop it.  The incidence of side effects with Finasteride is very low however if you suffer side effects, then you should probably avoid taking it.  If you are only 22 and have such significant hair loss - you need to keep in mind the future loss you will have when designing your hair transplant with your doctor - approach this very cautiously and conservatively. 

Use Rogaine only if you used it before the hair transplant as your hairs will have become depenent upon this medication. 

You are quite young to have lost 50% of your hair. Unless you are incorrectly describing yourself, you should consider a hair transplant with caution. Rogaine can work but the long term is questionable. Finasteride(Popecia) works better in my opinion. The side effects reported  occur in a very small percentage of patients.