11.1 Facial Hair Color, Overprocessed Hair & Metallic/Compound Dyes

Most haircoloring services on the PSI theory exam involve straightforward application and formulation. This section covers the situations that trip up even experienced stylists: services the law prohibits outright, dyes that silently sabotage every other chemical service in the salon, and hair that has already been damaged beyond what more chemical exposure can fix. These are heavily tested because they combine legal liability, chemistry, and client safety in ways that a single wrong answer can genuinely hurt someone.

Eyebrow and Eyelash Tinting: A Legally Restricted Service

Tinting eyebrows and eyelashes with permanent haircolor or aniline-derivative dye is one of the most consequential prohibitions in cosmetology law, and it appears on nearly every state theory exam because the consequences of ignoring it are severe and irreversible.

Why the FDA Prohibits It

The U.S. Food and Drug Administration (FDA) has never approved any coal-tar (aniline-derivative) dye for use on eyelashes or eyebrows, even though the same dyes are approved for scalp hair. This is not an oversight — it reflects documented harm:

• The skin around the eyes is thin and highly permeable, absorbing chemicals more readily than the scalp
• Dye that runs or drips can enter the eye directly
• Severe allergic reactions near the eye have caused corneal ulceration, permanent scarring, and blindness
• Unlike a scalp reaction, an eye-area reaction can cause irreversible injury within minutes

Regulatory Note: Every FDA-approved permanent haircolor product carries a required warning label stating it must not be used to dye eyelashes or eyebrows, and that doing so could cause blindness. Cosmetologists must read and honor this label regardless of client requests.

What This Means in the Salon

Most state boards, including Michigan's, prohibit licensed cosmetologists from tinting eyelashes or eyebrows with dye in a licensed establishment. Only specially formulated, cosmetic-grade lash/brow tints that do not contain aniline derivatives — and that are permitted under state-specific rules — may be used, and even those require a patch test and strict adherence to manufacturer directions. Applying mascara or a temporary, non-permanent eyebrow/lash cosmetic is a separate, permitted category and should not be confused with chemical tinting.

Client Communication: If a client requests eyelash or eyebrow tinting with hair color, the correct professional response is to explain that this is not a legally permitted service and offer an approved alternative (such as brow tinting products specifically licensed for that use, where state law allows, or referral to a service that offers FDA-compliant lash/brow tinting).

Metallic and Compound Dyes

Metallic dyes (also called mineral dyes) contain metallic salts — most commonly lead acetate, but also silver nitrate, bismuth, or copper compounds — that gradually darken hair through repeated application. They are frequently sold as "progressive color restorers" or "gradual gray coverage" products marketed directly to consumers rather than professionals.

How Metallic Dyes Work

Unlike aniline-derivative tints, which form color molecules inside the cortex through oxidation, metallic dyes deposit a visible metallic coating on the outside of the hair shaft with each application. The color builds gradually over days or weeks of repeated use, which is why these products are attractive to consumers who want a low-effort, incremental change.

Compound Dyes

Compound dyes combine a vegetable dye (most often henna) with a metallic salt to intensify or alter the natural henna color and speed processing. A product might be labeled or marketed as "natural henna" while still containing metallic compounds — this is precisely why compound dyes are considered more dangerous than either pure vegetable dyes or straightforward metallic dyes: the metallic content is often undisclosed or downplayed.

Why Metallic Salts Are Dangerous During Other Chemical Services

Hair coated with metallic salts reacts unpredictably and dangerously when exposed to the alkaline and peroxide-based chemicals used in permanent waving, chemical relaxing, and standard aniline-derivative haircoloring:

• Discoloration — hair can turn shades of green, black, or even change texture color unpredictably
• Excessive, uncontrollable heat — the chemical reaction between metallic salts and peroxide/ammonia-based products can generate enough heat to scorch or burn the scalp and severely damage the hair
• Hair breakage — the combination can cause the hair to become brittle and break off, sometimes during processing
• Unpredictable processing — normal timing guidelines no longer apply because the chemistry is contaminated

Client History Warning: Clients rarely know whether a home color product they purchased contains metallic salts, because these ingredients are not always prominently disclosed. Never assume a client's self-applied color is free of metallic salts just because they call it "natural" or a "color-enhancing shampoo."

The Metallic Salt (Test Tube) Test

Because visual inspection cannot reliably detect metallic salts, cosmetologists use a chemical test before performing any chemical service (permanent wave, relaxer, or aniline-derivative color) on hair with an unknown or suspicious chemical history:

1. Cut a small strand of the client's hair and place it in a glass test tube
2. Add a mixture of 20-volume peroxide and 28% ammonia water (approximately 20 parts peroxide to 1 part ammonia)
3. Cover the tube and observe for several minutes without shaking
4. A positive result (metallic salts present) shows bubbling, discoloration, a noticeable odor, or heat given off by the mixture, and the strand may change color
5. A negative result shows no reaction, indicating it is likely safe to proceed with the planned chemical service

Rule of Thumb: Always perform a metallic salt test before any chemical service when the client has colored their own hair at home, cannot confirm what product was used, or shows any inconsistency in color from root to end. If metallic salts are detected, do not proceed with the chemical service — recommend a strand test after several shampoos or a gradual grow-out and clarifying treatments instead.

Overprocessed Hair

Overprocessed hair results from excessive, repeated, or overlapping chemical treatment — most commonly overlapping lightener or relaxer application onto previously treated hair, using developer volumes stronger than needed, or leaving chemical services on longer than directed.

Signs of Overprocessed Hair

Causes of Overprocessing

• Applying lightener or relaxer over previously treated (not just virgin) hair without adjusting timing or strength
• Overlapping product onto already-processed lengths during a retouch, rather than confining new product to new growth
• Leaving chemical services on longer than the manufacturer directs, or skipping timed strand testing
• Combining two harsh chemical services too close together (for example, a relaxer followed shortly by a lightening service)
• Using a developer volume higher than necessary for the desired result

Corrective Approach

Overprocessed hair cannot be un-processed. The professional response is damage control, not further chemical exposure:

• Stop and reassess before applying any further chemical service — do not proceed with color or texture services on hair that already shows overprocessing signs
• Protein fillers and reconstructive treatments can temporarily restore some strength and evenness of porosity, making hair more receptive to gentle color deposit
• Deep conditioning treatments address moisture loss but do not repair structural protein damage
• Trim or cut away the most severely damaged sections when reconstruction is not sufficient
• Document and educate — record the condition and services performed on the client record card, and clearly explain to the client why additional chemical services must be postponed

Professional Standard: A cosmetologist's ethical and legal obligation is to protect the client's hair and scalp health. Proceeding with a requested chemical service on hair that is already overprocessed — even if the client insists — can result in further breakage, scalp injury, and liability for the salon.