Chemical Texture Services
The chemistry in one sentence
Permanent waves and relaxers break disulfide bonds, reshape the hair, then rebuild those bonds during neutralization (or, for hydroxide relaxers, remove the need to rebuild by lanthionization). Everything else in this domain is a variation on that idea.
Know the products
- Ammonium thioglycolate (alkaline wave), pH roughly 9.0–9.6, requires a thio neutralizer.
- Acid waves, pH roughly 4.5–7.0, are gentler but slower; GMTG (glyceryl monothioglycolate) requires heat and has a high sensitization rate.
- Bisulfite waves are low-pH and mild. Hydroxide relaxers (sodium, potassium, lithium, guanidine) are strongly alkaline, do not require neutralization, and are not compatible with thio products. No-base relaxers contain a protective agent in the cream; base relaxers require a protective base applied to the scalp.
Analysis before every service
Porosity, elasticity, density, and texture plus a strand test and, when the manufacturer requires it, a patch test 24–48 hours ahead. Never relax hair that has been lightened to the point of breakage; do not pull a relaxer through previously relaxed length.
Rods, base control, and timing
- Rod diameter determines curl size; rod length and wrapping pattern determine base control: on base (maximum volume), half off base (medium), off base (minimum).
- Processing is timed by the manufacturer and checked by test curl, never by the clock alone.
Worked example
A client with resistant, medium-porosity hair wants firm curl. Choose a thioglycolate wave, wrap on half off base with small-diameter rods, process per manufacturer, rinse thoroughly, blot, then apply neutralizer for the full time - under-neutralizing leaves the wave weak and the hair fragile.