13.3 Chemical Relaxers & Curl Re-Forming

Relaxing: The Reverse of a Perm

A chemical hair relaxer straightens extremely curly or coily hair by the same bond-breaking logic as a perm, run in reverse: the disulfide bonds are broken, the hair is physically smoothed straight instead of wrapped on rods, and the bonds are re-formed in the straight configuration. Because the chemistry is aggressive, this is one of the highest-liability services in the salon — and a heavily tested one.

Hydroxide Relaxers

Hydroxide relaxers are ionic compounds that swell the hair and break the disulfide bonds so strongly that the conversion is permanent — the broken sulfur links are rebuilt as lanthionine bonds during neutralization, which is why hydroxide relaxing cannot be reversed by shampooing or time. The hydroxide family includes:

• Sodium hydroxide (NaOH) — the oldest and strongest type, historically called a lye relaxer, with a pH as high as about 12.5-13.5. Because of its strength, the scalp is traditionally protected with a base cream (a petroleum-based protective cream applied to the scalp and hairline before the relaxer).
• Lithium hydroxide and potassium hydroxide — marketed as no-lye relaxers; chemically still hydroxides, slightly less aggressive than sodium hydroxide.
• Calcium hydroxide — a common no-lye formula, often sold in no-base versions for home or salon use.
• Guanidine hydroxide — a no-lye relaxer sold as two components that must be mixed immediately before use. It is generally gentler on the scalp but more drying to the hair, so it demands diligent conditioning.

The exam distinction that trips people up: no-lye does not mean no-hydroxide and does not mean mild or damage-proof. All hydroxide relaxers straighten by the same harsh mechanism and all can burn the scalp if misapplied.

Thio relaxers use the same ammonium thioglycolate chemistry as permanent waving lotion (pH around 9-10). They soften the disulfide bonds through reduction, the hair is combed straight, and an oxidizing neutralizer rebuilds the bonds. The critical rule: thio and hydroxide products are incompatible — never apply one over hair previously treated with the other. Taking a chemical history is therefore not a courtesy; it determines which chemistry the client can safely receive.

Strengths, Application, and Neutralizing

Relaxers come in strengths matched to the hair — typically mild, regular, and super (resistant) — chosen by texture and porosity: fine, porous, or damaged hair takes the mildest effective strength; coarse, resistant new growth may need super. Overlapping a strong formula onto fragile hair is a classic breakage scenario.

Application splits into two cases:

• Virgin application — the first relaxer on never-relaxed hair, applied to the whole strand, usually starting away from the scalp and ends (which process faster) and finishing at those areas.
• Retouch application — applied to new growth only. The single most tested rule in this topic: never overlap relaxer onto previously relaxed hair. Previously relaxed hair is already straight and has already lost bond strength; overlapping breaks it off at the line of demarcation.

During processing the hair is smoothed with the back of the comb or fingers per manufacturer directions, with a timer set the moment application begins — processing time is the primary control against overprocessing. When processing is complete, the hair is rinsed thoroughly with warm water, then shampooed repeatedly with a neutralizing shampoo — an acid-balanced shampoo, often with a color indicator — until the lather stays white and no pink remains, confirming all relaxer residue is gone. A built-in conditioner or normalizing step follows.

Curl Re-Forming and Keratin Treatments

Curl re-forming (the soft curl permanent) combines both services: a thio relaxer first loosens the natural curl, the hair is then wrapped on large rods, and neutralizer sets the new, larger curl pattern. It is tested mostly at awareness level — know that it exists, that it uses thio chemistry, and that it never follows a hydroxide relaxer.

Keratin smoothing treatments are a different category entirely. They are temporary — lasting weeks rather than growing out like a relaxer — and they work by coating the hair and sealing it with heat, not by breaking disulfide bonds. Because they leave the natural curl pattern to return gradually, no line of demarcation forms. The safety issue is the ingredient list: many formulas release formaldehyde gas or methylene glycol when flat-ironed, so the exam expects you to know that these services require manufacturer-directed application, proper ventilation, and awareness of exposure limits for both stylist and client.

Relaxer Chemistry Comparison

Safety checklist the exam rewards: consultation and chemical history, strand test, scalp examination for abrasions (do not relax over irritated skin), base cream where required, timer, no overlap on retouches, thorough rinse, and neutralizing shampoo until the lather is white. When a scenario asks what went wrong with a client whose hair broke off an inch from the scalp, the answer is almost always overlap or overprocessing — both are prevented by that checklist.