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5. Chemical Reforming (Perming & Chemical Relaxing) Chemical texture reforming permanently alters straight hair into curls or breaks coily patterns into straight alignments. This transformation requires two chemical steps: disulfide bond reduction followed by oxidative bond rebonding.

5.1 Redox Reactions in Chemical Waving

Permanent waving relies on a classic Reduction-Oxidation (Redox) reaction:

1. Reduction Step (Waving Lotion) Ammonium

Thioglycolate

(ATG)

or

2. Mechanical Wrapping

Cysteamine

Hair strands conform to the physical diameter of

penetrates the cortex, donating hydrogen atoms to break

wrapped perm rods, shifting broken disulfide bonds into

cystine disulfide bonds into separate cysteine thiol

newly aligned spatial configurations.

groups.

3. Neutralization Step (Oxidizer)

4. Alkaline vs. Acid Perms

Hydrogen peroxide neutralizer removes hydrogen atoms,

Alkaline perms (pH 9.0–9.6, cold waves) act fast on

reforming broken disulfide bonds in their new curler-

resistant hair. Acid perms (pH 6.9–7.2, heat-activated)

conformed shape while lowering pH.

suit damaged, color-treated strands.

5.2 Chemical Hair Relaxers & Incompatibilities

Chemical relaxers straighten hair by permanently converting strong disulfide bonds into lanthionine bonds through a process called lanthionization.

Active Chemical

Operational pH

Compound

Range

Sodium Hydroxide

NaOH (2% – 3%

pH 12.5 – 14.0

Fast-acting; requires scalp protective base cream.

(Lye)

concentration)

(Extreme)

High chemical burn risk.

Relaxer Type

No-Lye Relaxers

Thio Relaxers

Guanidine / Calcium Hydroxide Ammonium Thioglycolate (ATG)

pH 11.0 – 11.5

pH 9.0 – 10.0

Key Safety Rules & Incompatibilities

Gentler on scalp, but can leave mineral buildup on hair fibers over time.

Uses same reduction chemistry as perms. Incompatible with Hydroxides!

Critical Chemical Hazard Notice

NEVER combine Sodium Hydroxide (Lye) relaxers with Ammonium Thioglycolate or metallic salt dyes! Applying hydroxide relaxers over thioglycolate-processed hair causes catastrophic chemical melting and total hair shaft degradation.

Hairdressing Science & Artistry: Professional Guide

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