AHA, BHA, and PHA in Korean Skincare: Read Beyond the Acronyms

AHA, BHA, and PHA are useful shopping labels, not strength ratings. Two Korean toners can print the same three acronyms on the front while using different acids, amounts, pH, bases, and directions. Read the complete formula and current label before deciding how often—or whether—to use one.

What the acronyms usually mean

• AHA commonly refers to alpha hydroxy acids such as glycolic, lactic, or citric acid.
• BHA on cosmetic labels most often refers to salicylic acid, although FDA notes that the consumer label and strict chemistry terminology are not identical.
• PHA commonly refers to polyhydroxy acids such as gluconolactone or lactobionic acid.

The acronym does not tell you whether an acid is present mainly to exfoliate, adjust pH, support the formula, or substantiate a front-label concept. Ingredient identity alone cannot reveal the finished product's exfoliating intensity.

Why percentage is only part of the answer

Declared concentration is more useful than guessing from ingredient order, but it still does not capture final pH, delivery, contact time, rinse-off versus leave-on use, or the rest of the formula. If a brand does not publish a percentage, record it as unknown. Do not convert a list position into a number.

Cosmetic exfoliant and acne drug are not interchangeable labels

In the United States, the FDA OTC acne monograph identifies salicylic acid at 0.5–2% as an active ingredient for qualifying topical acne drug products. That does not mean every cosmetic containing salicylic acid is an acne drug, nor that a lower cosmetic amount is ineffective for every intended formulation purpose. Claims, labeling, concentration, and regulatory category all matter.

Sun sensitivity and irritation deserve routine-level attention

FDA guidance says topically applied AHA cosmetics may increase sensitivity to sunlight and the possibility of sunburn during use and for up to a week after stopping. FDA also advises patch testing BHA cosmetics, following label directions, stopping if irritation or prolonged stinging occurs, and using sun protection.

Adding several acid toners, pads, serums, and masks can duplicate exposure even when each product looks mild by itself. Introduce one product at a time and avoid interpreting tingling as proof that it works.

A practical label-reading sequence

1. Confirm the exact product and market. Similar names can have different formulas.
2. Find the named acids. Distinguish glycolic, lactic, citric, salicylic, gluconolactone, and lactobionic acid.
3. Record only declared amounts. Keep ppm as ppm and unknown as unknown.
4. Read directions and warnings. Frequency and contact time are part of the product evidence.
5. Check routine duplication. Count other exfoliating products before adding another.
6. Protect exposed skin. Follow the current label and use appropriate sun protection.

This guide is educational, does not diagnose acne or other skin conditions, and cannot predict irritation. Seek professional advice for persistent, painful, scarring, or suddenly worsening symptoms. For the limits of ingredient order, read our INCI guide.