When applied to the Art of Beauty, the Science of Chemistry has brought us the ability to give
most women nearly any look they want from their hair. At the very least it can be said that chemical sciences has given us a wide range
of looks that one can achieve from virtually any hair type. We can give a natural brunette, shiny golden locks, and the mousy-haired girl a fiery mane of rich red.
We can also take the straight hair and make it curl (and vice versa). When the chemical wave
was developed, it was a breakthrough for many women who had long undergone repetitive and sometimes torturous treatments to get the
curls they desired. (Look into the history of cosmetology sometime and see the kinds of strange and dangerous treatments that some
women underwent in the name of beauty.)
Fortunately for us, the first chemical waves were developed back in 1941 and the science has
not stopped evolving. Today we have Alkaline Waves, True Acid Waves, Acid-Balanced Waves, Exothermic Waves, Endothermic Waves,
Ammonia-Free Waves, Thio-Free Waves, and Low-pH Waves – to name the most common types.
Each formulation of permanent wave has its own reasoning and purpose for being, since
there are so many different hair types. It’s important to understand permanent waving and the pros and cons of the different
formulations in order to know what’s best for a given individual’s hair. Let’s look at the various Permanent Wave types, what makes
them special, and for which hair type and condition they are best suited:
(click to enlarge)
Alkaline (or Cold) Waves
Alkaline waves are perhaps the most commonly used wave type because they are ideal for
creating firm, lasting curls. Alkaline waves contain Ammonium Thioglycolate as a key ingredient, and process quickly at room temperature
without having to apply additional heat (usually within 20 minutes). Most alkaline waves have a pH between 9.0 and 9.6.
Due to the strength of the formulation of most Alkaline waves, they are ideal for use on
coarse, thick and resistant hair types to give a firm, strong curl. However, they often have a strong, unpleasant ammonia odor, and can damage delicate hair types.
True Acid Waves
The first “true” acid waves were introduced in the early 1970s and use Glyceryl
Monothioglycolate as the key ingredient. Because they have a pH between 4.5 and 7.0 typically, they process much more slowly and
usually require the application of heat from an outside source to process the hair.
The comparative mild formulation of an acid wave means it is much gentler on the hair, but
also means that the processing will take longer and the resultant curl is often less firm than that achieved with alkaline perms. Acid
waves are ideal for use on extremely porous hair or hair that has been very damaged, while it is likely to be of little effect on coarser or more resistant hair types.
Note: All acid waves have three components: a waving solution, an activator, and a
neutralizer. The activator contains the agent Glyceryl Monothioglycolate (GMTG) and should be considered carefully before deciding
to use an Acid Wave since repeated exposure to GMTG is known to cause allergic sensitivity in both stylists and clients.
Because of the level of added effort and difficulty in processing a True Acid wave, the
strength and pH of acid waves has been increased over the years to allow for easier, and simpler processing. Most acid waves found in
salons today have a pH of between 7.8 and 8.2 which isn’t truly acidic. These are now called Acid-Balanced Waves.
In addition to speeding up the processing and allowing for the wave to process at room
temperature, and without the need for use of a hair dryer to provide added heat. Acid-balanced waves create firmer curl results that
a true acid wave. They are great for use with hair that is porous and possibly damaged because they are gentler than most alkaline waves.