AHA vs BHA vs PHA: Which Exfoliant Is Right for You?
Last updated: Aug 2026
Quick answer: AHA, BHA, and PHA are three types of chemical exfoliant that dissolve dead skin cells instead of scrubbing them off. AHAs (like glycolic and lactic acid) are water-soluble and work on the skin's surface — best for dryness, dullness, uneven texture, and dark spots. BHA (salicylic acid) is oil-soluble, so it gets inside pores — best for oily and acne-prone skin, blackheads, and congestion. PHAs (like gluconolactone and lactobionic acid) have larger molecules that exfoliate more slowly and gently — best for sensitive or reactive skin. The simple rule: AHA for dry/dull skin, BHA for oily/acne-prone skin, PHA for sensitive skin. Whichever you choose, start slow (once or twice a week) and wear sunscreen daily, since exfoliated skin is more sun-sensitive.
Standing in front of a wall of "acid" products with no idea which one you need? Here's the clear breakdown of AHA, BHA, and PHA — and how to pick the right one for your skin.
What are chemical exfoliants?
Chemical exfoliants are acids that loosen and dissolve the bonds holding dead skin cells together, so they shed evenly. Unlike physical scrubs — which can cause micro-tears and irritation — chemical exfoliants work gently and uniformly, revealing smoother, brighter skin underneath. AHA, BHA, and PHA are the three main families, and they differ mainly in molecule size and whether they're water- or oil-soluble.
What is AHA?
AHAs (alpha hydroxy acids) are water-soluble acids that exfoliate the surface of the skin. The most common are glycolic acid (smallest molecule, most potent) and lactic acid (larger, gentler, also hydrating). Mandelic acid is a gentler AHA good for sensitive or acne-prone skin.
Best for: dryness, dullness, rough texture, fine lines, and dark spots/uneven tone. AHAs are the go-to for brightening and smoothing.
What is BHA?
BHA (beta hydroxy acid) usually means salicylic acid, which is oil-soluble — the key difference. Because it dissolves in oil, it can penetrate into your pores and clear out the sebum, dead skin, and debris that cause blackheads and breakouts. It's also anti-inflammatory.
Best for: oily skin, acne-prone skin, blackheads, whiteheads, clogged pores, and congestion.
What is PHA?
PHAs (polyhydroxy acids) — like gluconolactone and lactobionic acid — work similarly to AHAs but have larger molecules. That means they penetrate more slowly and stay closer to the surface, making them the gentlest of the three. They also have hydrating and antioxidant properties.
Best for: sensitive, reactive, or easily-irritated skin, and anyone who finds AHAs or BHA too strong.
AHA vs BHA vs PHA: comparison table
| Feature | AHA | BHA | PHA |
|---|---|---|---|
| Examples | Glycolic, lactic, mandelic | Salicylic acid | Gluconolactone, lactobionic |
| Solubility | Water-soluble | Oil-soluble | Water-soluble |
| Where it works | Skin surface | Inside pores | Surface (gentle) |
| Molecule size | Small–medium | Small | Large |
| Gentleness | Moderate | Moderate | Gentlest |
| Best for | Dryness, dullness, dark spots | Oily/acne skin, blackheads | Sensitive skin |
| Bonus | Brightening, anti-aging | Anti-inflammatory | Hydrating, antioxidant |
Which exfoliant is right for your skin?
- Dry, dull, or sun-damaged skin, or dark spots → AHA (glycolic or lactic)
- Oily or acne-prone skin, blackheads, clogged pores → BHA (salicylic)
- Sensitive, reactive, or redness-prone skin → PHA
- Combination skin → you might use BHA in oily areas and AHA elsewhere, or a product that blends them
If you're unsure, start with the gentlest option that fits your concern and see how your skin responds.
How to use exfoliating acids safely
- Start slow — once or twice a week, building up only if your skin stays comfortable
- Apply to clean, dry skin, usually at night
- Don't stack multiple exfoliants (or exfoliants plus retinoids) when starting out
- Follow with moisturizer to keep the barrier happy
- Wear sunscreen every morning — exfoliation increases sun sensitivity, and skipping SPF undoes the benefits and risks damage
- Watch for over-exfoliation — tightness, redness, stinging, and breakouts mean you're doing too much; scale back
Can you use AHA, BHA, and PHA together?
You can, but you usually don't need to, and stacking them raises the risk of over-exfoliating. Many products already blend acids for you. If you want more than one, alternate them on different nights rather than layering them all at once — and if your skin is sensitive, stick to one gentle option.
Frequently asked questions
What's the difference between AHA and BHA? AHA is water-soluble and exfoliates the skin's surface (best for dryness and dullness); BHA is oil-soluble and gets into pores (best for oily, acne-prone skin). The solubility is the key difference.
Which is best for acne? BHA (salicylic acid), because it's oil-soluble and can clear out clogged pores from the inside. AHAs help with post-acne marks and texture on the surface.
Is PHA better than AHA? Not better — gentler. PHAs have larger molecules that exfoliate more slowly, making them ideal for sensitive skin that finds AHAs too strong. AHAs work faster but can be more irritating.
How often should I use a chemical exfoliant? Start with once or twice a week. Daily exfoliation is too much for most people and leads to a damaged barrier. Adjust based on how your skin responds.
Do I need sunscreen if I use acids? Yes, absolutely. Chemical exfoliants make your skin more sensitive to the sun, so daily broad-spectrum SPF is essential — both to protect your skin and to keep your results.
The bottom line
AHA, BHA, and PHA all exfoliate chemically, but for different skin: AHA for dry, dull, or spot-prone skin; BHA for oily and acne-prone skin; PHA for sensitive skin. Pick the one that matches your concern, start slow, moisturize, and never skip sunscreen. Done right, the right acid transforms texture, tone, and clarity — without a single scrub.
Not sure which acid your skin needs? Explore Llusso's AHA, BHA, and PHA exfoliants and start gently. Link to relevant collection.
