Chemical Services and Scalp/Hair Treatments
Know the bonds
Permanent waves and chemical relaxers both work by breaking disulfide bonds and rebuilding them in a new shape. A perm breaks bonds with ammonium thioglycolate (alkaline waves, pH about 9.0–9.6) and re-forms them with a neutralizer such as hydrogen peroxide or sodium bromate. A relaxer breaks bonds with sodium hydroxide (lye) or with calcium hydroxide and guanidine (no-lye), and the process is stopped with a neutralizing shampoo. Hydrogen bonds, by contrast, are broken by water and re-formed by drying - that is why wet setting and blow-drying shape hair without chemicals.
Client protection
Every chemical service begins with a patch test (typically 24–48 hours before an aniline-derivative tint) and a strand test to judge processing time and result. Base the scalp before a relaxer, do not shampoo immediately before one, and never relax hair that is metallic-dyed or overprocessed, or a scalp with abrasions.
Scalp and hair treatments
Scalp treatments, massage, and conditioning are contraindicated over open lesions, contagious conditions, or unexplained scalp disorders. Distinguish a dry, flaky scalp from a fungal infection; the latter is referred out.
Traps
- Mixing up the neutralizer used for waves and the neutralizing shampoo used for relaxers.
- Assuming an acid-balanced product is a relaxer; acid-balanced shampoos simply have a low pH.
- Forgetting that color and lighteners require the correct developer volume plus a strand test.
Rule of thumb
Break the bonds, then restore them: no wave without neutralizer, no relaxer without neutralizing shampoo.