Ammonia-free waves are generally suited to use on hair that is porous to normal in resistance
level, processes at room temperature, and typically generates medium to fine curls. While these waves may not smell as strongly as
ammonia, they can still be every bit as alkaline and just as damaging. Remember that ammonia-free doesnít mean damage-free.
Thio-Free Waves use a substitute for Ammonium Thioglycolate (ATG) as the primary reducing
agent in the waving formula. Commonly, the substitutes used are cysteamine or mercaptamine which while not technically being ATG are
still thio compounds. Thio-Free Waves are marketed as being damage-free, but this isnít necessarily true. In high concentrations these
can be as damaging as thio to the hair.
Thio-Free Waves have the benefits of processing at room temperature, and produce medium to
fine curls. The Thio-Free Wave is suited for use on normal to porous hair types, and can be gentler on the hair depending on the
individual formula used. Since the strength varies from manufacturer to manufacturer be sure to use caution in selecting and using a new formula.
Low-pH waves use an alternative formula for their waving solutions. Instead of Ammonium
Thioglycolate, low-pH waves use sulfates, sulfites and bisulfites as their primary ingredients. These formulations are very gentle
since they work at a low pH, but while they have been in use for years, they are not very popular. The trouble is that the permanent
waves based on sulfites are very weak and do not provide firm curls. Because of this they are often marketed for use in body wave services.
The weak formulation of Low-pH waves make them suited for use with fine and damaged hair or
in cases where a gentle wave is desired as opposed to firm curl. Low-pH waves are endothermic waves and will need the heat of a hair dryer.
So, as you see, there are many options available when you start looking for a permanent wave
formula. Knowing what the different terms mean and how they differ can help you select the right option for your hair, and help you
know whether this is going to be something you can manage on your own. Just remember that if you are unsure, always ask a professional
for guidance, or at the very least try to err on the side of caution.