The spiral curl perm is more traditional, leaving you with tight, uniform curls. Some shy away from this type of perm because it can cause your hair to look unnatural in some cases. But if you choose a reputable stylist who knows how to set your hair properly, you could walk away with natural-looking voluminous curls. Spiral perms give your thin hair an enormous boost - the most dramatic change out of all of the perm types mentioned in this article. You can personalize your spiral curls by selecting different roller sizes - go for straw-sized curls for the most volume or larger curls (marker to sidewalk chalk-sized) for a more subtle change.