Chemical Texture Services: Permanent Waving and Relaxing
Break, then rebuild
The chemistry is simple and heavily tested: permanent waving and relaxing break disulfide bonds with a reducing agent; the neutralizer rebuilds them in the new shape by oxidation. Anything that reduces must be neutralized, or the hair stays weak.
Alkaline waves use ammonium thioglycolate at about pH 9 and process without added heat; acid waves use glyceryl monothioglycolate at a lower pH and usually need heat. Neutralizers are hydrogen peroxide or sodium bromate. Relaxers: sodium hydroxide (lye, pH 12–14, base or no-base formula), guanidine (no-lye), and ammonium thioglycolate thio relaxers, which are milder and typically need no base. Strength (mild, regular, super) matches texture and previous processing.
Analysis precedes the service: porosity, elasticity, density, texture, and any history of lightener, relaxer or henna. Never relax over a thio relaxer or metallic salts without checking compatibility.
Traps
- A retouch goes on new growth only; pulling relaxer through previously relaxed hair causes overlapping and breakage.
- Neutralizing shampoo is not optional; incomplete neutralization leaves residual alkalinity that keeps processing.
- A test curl tells you processing is complete; it is not a substitute for a strand test before you start.
- Scalp abrasions, recent shampooing or scratching are reasons to postpone.
Rule of thumb
Same logic, both services: reduce to change the shape, then oxidize to lock it in. If the neutralizer step is skipped, the service is not finished.