Chemical Texture Services on the Cosmetology Exam: Perms, Relaxers, and Smoothing

Where chemical texture sits in the NIC theory outline

The current bulletin for the NIC National Cosmetology Theory Examination (effective July 1, 2022, revised January 1, 2026) places chemical texture inside Hair Care and Services, the domain worth 45% of the exam. Three outline lines cover it:

• Perform chemical hair relaxer, restructurizer, and curl reduction services, with hydroxide, thio, and keratin given as examples.
• Perform chemical waving and texturizing services, with alkaline, acid, and non-thio given as examples.
• Understand the chemical products used for the various hair texture types.

Scientific Concepts, the 35% domain, adds two chemistry lines: recognize interactions between chemicals, and recognize chemical reactions such as overexposure and chemical burn. The consultation lines also apply: recognize contraindications, use preliminary tests such as the strand test, and keep client records with service history. So a chemical texture question can look like a consultation, chemistry, or safety question. NIC still posts this bulletin as of October 28, 2026 and has announced no replacement, so these are the lines a 2027 candidate in an NIC state should expect.

What relaxers, perms, and smoothing treatments do to the hair

A 2015 review in the International Journal of Trichology explains the shared mechanism. The hair's shape is held in the cortex, the inner bulk of the shaft, partly by disulfide bonds, and chemical texture services work on those bonds. Alkaline solutions swell the fiber and open the cuticle scales, which is how an active ingredient reaches the cortex.

The hydroxide and thio compatibility decision

The same 2015 review states plainly that hydroxides and thioglycolate are incompatible with each other. Hair already treated with a hydroxide cannot then be treated with thioglycolate, and the review lists bleached hair as incompatible with both. It adds that highlights or light shades are "absolutely incompatible" with chemical relaxers. A related timing rule comes from the FDA's consumer fact sheet on hair dyes and relaxers: wait at least 14 days after bleaching, relaxing, or perming before using dye.

On an exam, the rule is easiest to test as a consultation scenario rather than a chemistry fact. Work it in this order:

1. Find out what is on the hair. Ask the client and check the client card for the product family, the date, and who applied it.
2. Do not guess when the history is unclear. The review describes a strand test to check compatibility before a full service, but a strand test does not make a known incompatible pairing safe. Follow the manufacturer's directions for previously treated hair.
3. Decline the conflicting service. Explain the reason in plain words and offer something that puts no second chemistry on the treated hair, such as a wet set or thermal style.
4. Record it. Write the request, the decision, and the reason on the client record.

A worked consultation (fictional client). Keisha had a no-lye hydroxide relaxer six weeks ago. She asks for a thio-based curl service on the same lengths because she wants more volume. Step 1 identifies a hydroxide relaxer, and because her history is clear, step 2 is not needed. Step 3 applies: a thio service over hydroxide-relaxed hair is the incompatible pairing, so the answer is to decline that service and offer a non-chemical style instead. Any option that says "do a strand test, then proceed if the hair holds up" misses the point, because the conflict is in the chemistry, not in how strong the hair looks.

When you can explain Keisha's case without notes, check the thio-over-hydroxide decision in the free cosmetology practice set. For the full domain, salon-scenario practice in Hair Care and Services, planned for launch, turns the same consultation logic into many more items.

Relaxer retouches: new growth only

The American Academy of Dermatology (AAD) gives the retouch rule in consumer terms: relaxer touch-ups should be done only every two to three months, only on newly grown hair, and relaxer should never be applied to hair that has already been relaxed. On a retouch question, the keyed answer keeps product on the regrowth and off the previously relaxed lengths, because overlapping processes those lengths a second time.

Recognizing overprocessing and chemical burn

The outline's phrase "overexposure, chemical burn" covers two things to recognize: a product left on too long, and a product damaging the skin. Public sources give four prevention points:

• Check the scalp first. The FDA's fact sheet says not to dye or relax hair when the scalp is irritated, sunburned, or damaged, and not to scratch or brush the scalp for three days beforehand.
• Keep the relaxer off the skin. The FDA says to avoid applying relaxer to the scalp and other skin areas because it can irritate or burn. The 2015 review adds a protective base of petrolatum along the hairline and ears, and links poor technique to scalp burns and hair breakage.
• Protect your own hands. Both the FDA and the Cosmetic Ingredient Review point to gloves, and the Cosmetic Ingredient Review panel noted that hairdressers applying hydroxide straighteners to several clients in a short period need to protect their skin.
• Time it. Do not leave the product on longer than the directions say. The FDA suggests a clock or timer.

The response to burning is a principle, not a memorized script. Stop the application and rinse the product out right away with plenty of cool running water. MedlinePlus's first-aid guidance for chemical burns says to flush the skin with cool running water for 15 minutes or more, not to try to neutralize the chemical without consulting poison control or a health care provider, and to get medical help right away for a second- or third-degree burn or a whole-body reaction. If product gets into the eyes, it says to flush them with running water for at least 15 minutes and get medical help right away. Then follow the product's directions and the first-aid section of its safety data sheet. A cosmetologist does not diagnose the injury or treat it beyond first aid, and does not finish the service on that scalp.

A worked reaction (fictional client). Twelve minutes into a relaxer retouch, Marisol says the crown is burning, and the skin there looks red. This is a chemical reaction in progress. Stop and rinse thoroughly at once, then check the skin and follow the product's first-aid directions. Refer her for medical care if the skin is broken or the pain is severe, and record the product, the timing, and what you saw. The tempting wrong answers sound efficient: "apply more base and finish quickly," "rinse when the timer ends," "switch to a milder relaxer." Each one keeps the chemical on injured skin.

To see whether that reasoning holds under exam wording, review the scalp-burning relaxer item in the free practice set. Read the explanation for each distractor, not only the key.

Keratin smoothing and formaldehyde

Smoothing treatments bring a different hazard. The FDA's page on hair smoothing products says formaldehyde released by the heated solution puts both salon professionals and clients at risk of breathing it if the salon is not properly ventilated. Reported reactions range from eye problems and headaches to breathing problems, nausea, and rash.

Keep the agency roles straight. The FDA regulates the product and its labeling, and professional-only products must still carry directions for safe use and any needed warnings, but the FDA says it has no authority over how salons operate. OSHA regulates workplace safety, including air quality, requires safety data sheets for products with hazardous chemicals, and has a formaldehyde standard. State and local authorities can set salon practices such as ventilation. The OSHA, EPA, and SDS guide walks through a safety data sheet section by section, and explanations that link safe calls to FDA and OSHA guidance in planned full prep apply the same agency logic question by question.

A chemical texture self-check before exam day

You are ready for this part of the NIC outline when you can do each of these from memory:

• Name the chemistry behind each outline example, from hydroxide and thio to acid and non-thio waves.
• Explain what a hydroxide relaxer and a thio product each do to the hair's bonds, and which change is permanent.
• State the compatibility rule and how you would confirm a client's history.
• Give the stop, rinse, and refer response to burning, and say why "finish quickly" is wrong.

Consultation, preliminary tests, and client records get their own page in the patch and strand test guide. The pH side of these products, including why each step on the scale is a tenfold change, is in the pH and chemistry guide, and product choice across curl patterns is covered in the textured and natural hair guide.

If one item on that list still feels shaky, Weak Spot drills planned for launch, five questions at a time, target the domain where your accuracy is lowest.