5.3 Chemical Hair Relaxing and Soft Curl Perms

Chemical Hair Relaxing and Soft Curl Perms

Chemical hair relaxing is a service that rearranges curly hair into a straighter, smoother form. Soft curl perms reform extremely curly hair into looser, larger, and more manageable curls. Both services involve chemical changes within the hair's cortex. A barber must understand the differences between sodium hydroxide, ammonium thioglycolate, and no-lye relaxers, along with application steps, strand testing, neutralization, and reforming services.

Types of Chemical Hair Relaxers

Chemical relaxers are formulated as highly alkaline products that swell the hair cuticle and break the internal disulfide bonds. There are three main types:

1. Sodium Hydroxide (Lye) Relaxers

Sodium hydroxide (NaOH) relaxers are the oldest and most common, operating at a pH of 12.5 to 13.5. Often called lye relaxers, they require no mixing and process rapidly. They straighten hair permanently through lanthionization, a process that permanently breaks disulfide bonds and converts them into lanthionine bonds containing only one sulfur atom. Lanthionine bonds cannot be reformed, so hydroxide relaxed hair is permanently straightened and cannot be permed or re-curled.

2. Guanidine Hydroxide (No-Lye) Relaxers

Guanidine hydroxide relaxers are marketed as no-lye relaxers and operate at a pH of 13.0 to 13.5. They are a two-component system: a relaxer cream and activator mixed immediately before the service. While slightly less irritating to the scalp than sodium hydroxide, guanidine hydroxide can dry out the hair shaft because the chemical reaction deposits calcium residue that makes the hair brittle.

3. Ammonium Thioglycolate (Thio) Relaxers

Ammonium thioglycolate (Thio) relaxers operate at a pH of 9.0 to 11.5 and use the same active reducing agent as permanent waves (ATG), but formulated in a thick cream base. Thio relaxers break disulfide bonds through reduction and are neutralized by an oxidizing agent (hydrogen peroxide).

Barber Exam Critical Warning: Hydroxide relaxers and Thio relaxers are completely incompatible. They use entirely different chemical pathways. If a Thio relaxer is applied to hair previously treated with a hydroxide relaxer (or vice versa), the hair will undergo extreme chemical degradation, dissolve, or break off at the scalp. A barber must perform a thorough client consultation to verify past chemical services before applying any relaxer.

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Relaxer Application Steps

Relaxer formulations are available in base and no-base formulas:

• Base Relaxers: Require the application of a protective base cream (petroleum jelly) to the scalp, ears, and hairline before applying the relaxer.
• No-Base Relaxers: Contain a protective cream that melts at body temperature, protecting the scalp. However, a protective base cream should still be applied around the entire hairline and ears.

Virgin Relaxer Application (Dry Hair)

1. Sectioning: Divide the dry hair into four quadrants.
2. Application: Wear gloves. Apply the relaxer to the most resistant area first, typically the back of the head.
3. Placement: Apply the chemical 1/4 inch to 1/2 inch away from the scalp and up to 1/2 inch from the ends. Do not apply directly to the scalp or porous ends initially.
4. Rationale: The heat from the scalp accelerates processing, and the ends are highly porous. Applying to the mid-shaft first ensures even processing. In the final few minutes of processing, smooth the relaxer down to the scalp and through the ends.
5. Smoothing: Use the back of a plastic tail comb or gloved fingers to gently smooth the hair shaft. Never scratch or scrape the scalp with the comb teeth.

Retouch Relaxer Application

For a retouch service, apply the relaxer only to the new growth, taking care not to overlap the product onto previously relaxed hair. Overlapping will cause severe hair thinning, breakage, and chemical damage.

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Strand Testing and Analysis

During the chemical relaxing service, the barber must perform periodic strand tests (specifically the finger test or comb test) to monitor the progress of the relaxation. The barber smooths a small section of hair with the back of a comb or gloved fingers. If the hair springs back into a curl pattern, it requires further processing. If the hair remains flat and straight without rebounding, the hair is sufficiently relaxed, and the chemical must be rinsed out immediately.

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Neutralization Protocols

The neutralization step differs dramatically based on the type of relaxer used:

Hydroxide Relaxers (Lye/No-Lye)

Hydroxide relaxers cannot be neutralized with hydrogen peroxide. Instead, the hair must be rinsed thoroughly with warm water to physically remove the relaxer. The barber must then apply an acid-balanced neutralizing shampoo (typically pH 4.5 to 6.0). This shampoo neutralizes any remaining alkaline hydroxide residue and lowers the pH of the hair. Many neutralizing shampoos contain a built-in color indicator (such as phenolsulfonphthalein) that turns pink if any relaxer residue remains in the hair and turns white once the hair is fully neutralized.

Thio Relaxers

After rinsing the Thio relaxer completely, the barber must apply an oxidizing neutralizer (hydrogen peroxide) to reform the disulfide bonds and lock the hair into its new straight state.

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Soft Curl Perm Reforming Services

A soft curl perm (often called a curl reforming service) is a two-step thio-based service designed to reform extremely curly hair into larger, looser curls.

1. Step 1 (Reduction/Straightening): A Thio relaxer (rearranger) is applied to straight-out or partially relax the natural curl. The hair is rinsed completely.
2. Step 2 (Re-curling/Oxidation): The damp hair is sectioned and wrapped around perm rods using a Thio waving solution (booster) to process. Once processed, the hair is rinsed, blotted, and a Thio neutralizer (oxidizer) is applied to lock in the new curl pattern.