11.2 Ingredients and Product Function

NIC Scientific Concepts I.H tests ingredients by function, not by brand. The functions you must match are cleanse, hydration, and protection, plus the acid and enzyme families that chemically exfoliate the stratum corneum. 68 Ill. Adm. Code 1175.710 tests product chemistry. 1175.835 places chemistry — understanding chemicals and their use in the 150-hour Scientific Concepts block and product knowledge as it relates to esthetics in the 500-hour Practices and Procedures block. 1175.120 then turns function into law: use the product as the manufacturer indicates, and do not use FDA-unapproved chemicals.

Function first: cleanse, hydrate, protect

Every item on a facial tray exists to do a job. Start with the job, then name the molecule.

Cleanse means lift oil, debris, makeup, and pollution without destroying the acid mantle. The working molecules are surfactants (surface-active agents): a water-loving head and an oil-loving tail emulsify sebum so it rinses away. Strong anionic surfactants such as sodium lauryl sulfate clean aggressively and can strip. Milder amphoteric (betaines) and nonionic (glucosides) systems are more typical of facial syndets. Cationic surfactants (quats) are more often conditioning or antimicrobial than a daily face wash.

Hydration means putting water into the stratum corneum and keeping it there. That is two different jobs stacked.

Humectants, emollients, and occlusives

• Humectants attract water. High-yield names: glycerin and hyaluronic acid (HA). Others you will see: urea, sodium PCA, propylene glycol, honey.
• Emollients smooth the gaps between corneocytes (plant oils, fatty esters, shea).
• Occlusives seal. Petrolatum is the textbook occlusive. Oils, dimethicone, and waxes also reduce TEWL.

A humectant without a seal on very dry air can pull water and then lose it. A petrolatum layer without a humectant can seal dryness in. Exam stems that say “draws water into the skin” want humectant / glycerin / HA. Stems that say “forms a barrier that reduces water loss” want occlusive / petrolatum.

Protection means reducing damage after the client leaves. Antioxidants neutralize free radicals from UV and pollution — vitamin C (ascorbic acid) and vitamin E (tocopherol) are the pair NIC expects. They are not a substitute for sunscreen. Sunscreen is protection in the literal sense:

• Traditional exam language calls titanium dioxide and zinc oxide physical/mineral filters and organic actives such as avobenzone chemical/organic filters.
• Do not turn that vocabulary into false physics: modern measurements show zinc oxide and titanium dioxide protect primarily by absorbing UV, while also reflecting or scattering a smaller portion. Organic filters also absorb UV and dissipate the energy. Combination filters are often used for broad spectrum.

After a peel, protection is not a retail upsell. The reliable exam decision is a labeled broad-spectrum SPF finish; the mineral-versus-organic name is product classification, not permission to claim that one family only scatters and the other alone absorbs.

Sunscreens are over-the-counter drugs. Zinc oxide or avobenzone will appear as active ingredients in a Drug Facts box (Section 11.3). Treat SPF as labeled drug chemistry, not as a lotion afterthought.

Acids, enzymes, and retinoids — function and Illinois depth

AHAs — glycolic (sugar cane, smallest common AHA molecule) and lactic (milk, larger and also hydrating), plus mandelic, citric, malic, and tartaric — are water-soluble. They loosen corneocyte cohesion on the surface. On the Illinois exam they are superficial tools only.

BHAs: salicylic acid is the name to memorize. It is oil-soluble, so it can enter sebum-filled follicles. That is why it is the acne-oriented acid: comedolytic and mildly anti-inflammatory. It is still a superficial chemical exfoliant when labeled for cosmetic / stratum corneum use. It is not a license to treat cystic acne as a medical disease, and it is not a medium-depth TCA.

Enzymes: papain (papaya) and bromelain (pineapple) are proteolytic — they digest keratin protein on the surface. Enzyme peels are often rinsed and are taught as among the gentler superficial options. They remain in-scope only as stratum corneum work.

Retinoids are vitamin A derivatives. Prescription molecules (tretinoin and related drugs) are medical. Cosmetic retinol belongs in home care, with sun-sensitivity counseling. An Illinois esthetician does not prescribe drugs, does not diagnose acne as a physician, and does not use a retinoid as a living-layer peel. Flag home-care retinoids on the intake: they thin the surface, increase peel and waxing risk, and are a reason to modify — not a reason to “go stronger.”

IDFPR’s 04/06/2026 line still applies to this ingredient list. A labeled superficial AHA, BHA, or enzyme that stays on the stratum corneum can be esthetics. A medium TCA or phenol intended for living layers is the practice of medicine, not a “stronger facial acid.”

Patch testing and predisposition

A patch test (sometimes called a predisposition test in older tint language) is a small amount of product on the inner arm, behind the ear, or along the hairline, read after the manufacturer’s window — often 24–48 hours. Use it when the product is new to the client, when the client has a history of contact dermatitis, and whenever the manufacturer requires it (tints, some depilatories, some acids). A negative patch test is not a lifetime allergy waiver. Hypoallergenic on a box is not a substitute for a patch test (Section 11.3).

Skip the service and refer if the test site is red, swollen, blistered, or intensely itchy. 1175.115 already forbids massaging inflamed, infected, or erupting skin. A “tiny” peel on a positive patch-test site is still a chemical service on inflamed skin.

Illinois 1175.120: manufacturer indication and the eyebrow-dye example

68 Ill. Adm. Code 1175.120(c) interprets dishonorable, unethical, or unprofessional conduct to include using products and chemicals that have not been approved by the United States Food and Drug Administration, or using those products contrary to the manufacturer indication for use. The rule’s own example is using hair dye meant for hair on the scalp for dyeing eyebrows.

Memorize the example. Scalp aniline dyes are not eyebrow or lash tints. The box that says the product is for scalp hair is the indication. Using it on brows because the shade matches is the exact unprofessional-conduct fact pattern IDFPR wrote down. Lash and brow tints, when in scope, are products indicated for that tissue, used as labeled, with eye protection and a patch test when required.

The same 1175.120 sentence catches a medium-depth TCA used as an “esthetician facial,” a peel left on longer than labeled because “her skin is thick,” two acids mixed that the manufacturer never combined, and an unapproved chemical sold online as a medical peel. 1175.115(d) adds a parallel rule for devices: use only within scope and consistent with the manufacturer’s intended use.

Cosmetics generally are not pre-market approved the way drugs are; color additives are a notable FDA exception. Read 1175.120 as a use rule: if the chemical is not approved for that use, or the manufacturer’s indication does not cover what you are doing, you stop.

Matching ingredients on the exam

If the stem gives an ingredient, answer with the function. If it gives a function, answer with the class. If it gives a brow tint done with scalp dye, answer with 1175.120, not with a favorite brand.