Since men typically do not curl their hair with curling irons or rollers, getting a permanent wave is the best way for a man to get curly hair. The process of permanent waves consists of wrapping hair around rods and using two solutions to put a permanent curl in the hair. Perms last until they grow out.
The size of the perm rod dictates the size of the curl. Hair should be long enough to go around the rod a minimum of one-and-a-half times. So, a man with roughly 1 inch long hair can get a perm, but with tight curls. Usually 2 inches or more of hair is recommended. It is also preferable that all the hair is at least that length so it all can get permed, as this results in a more natural look.
Men can do their own permanent waves, or they can get them done in a salon. The process involves sectioning out the hair, applying end papers to segments, rolling strands evenly onto the perm rods, applying the processing solution, rinsing and neutralizing the hair.
Men who already have color or highlights in their hair are not good candidates for perms, according to About.com. Doing a second chemical process on the hair causes damage. After a perm, it's necessary to wait 48 hours before shampooing to allow the hair time to recover its natural pH.