Chemical Services: Permanent Waving and Relaxing
Chemical texture items test the science of breaking and re-forming disulfide bonds, product selection, test strands, and neutralization. You must separate waving chemistry from relaxer chemistry and recognize when hair is too damaged for either.
Chemistry
- A permanent wave uses a reducing agent to break disulfide bonds, wrapping to shape the hair, and a neutralizer to re-form the bonds.
- Alkaline waves commonly use ammonium thioglycolate at pH 9.0 to 9.5; acid waves are about pH 6.5 to 7.0 and usually need heat.
- Relaxers use sodium hydroxide at pH 12 to 14, or no-lye calcium hydroxide or guanidine systems; both break bonds, and a neutralizer stops the process.
- A relaxer is not a wave; do not confuse the two products or their neutralizers.
Procedure and safety
- Analyze porosity and elasticity, perform a test strand, and follow the manufacturer's patch-test and timing instructions.
- For a relaxer, base the scalp, apply to new growth only, smooth, rinse thoroughly, neutralize until pH paper shows normal, then condition.
- For a wave, wrap evenly, saturate, process, test curl, rinse, neutralize, and blot.
- Avoid relaxing over metallic salts or badly damaged hair.
Worked example
A client with previously tinted, porous hair wants a wave. The test strand shows poor elasticity. Choose an acid wave with lower pH and heat, process conservatively, and neutralize fully. An alkaline wave could overprocess the hair and cause breakage.
Traps that cost marks
Overlapping relaxer onto previously relaxed hair, skipping neutralization, wrapping with too much tension, rinsing insufficiently, using neutralizer as shampoo, and assuming no-lye products are safer.