Alkaline perms are the more common hair treatment compared to an acid perm. It is made up of a lotion with ammonium thioglycolate, and there is no need for any heat to activate the chemical because it activates in 20 minutes. It is potent, as it has a pH balance of between 8.2 and 9.6. The smell is due to the ammonia and is for thick hair because it gives a tighter, stronger curl that lasts longer.
The major drawback is that it is incredibly damaging to the hair. An acid perm, on the contrary, is made of glyceryl monothioglycolate. It has a PH total of 4.5 and 6.5. Heat is necessary to stimulate the chemical, and it takes longer for the hair to set.
It is gentler and creates a looser curl, but it takes less time to relax. It can sometimes trigger allergic reactions when the scalp and skin are exposed to its active ingredient. Most people prefer alkaline perms to acid perms because it is more convenient to use, and hair stays curly for longer.