PHA or AHA for sensitive skin?

Is PHA gentler than AHA?

Yes, generally. PHA means polyhydroxy acid, a related generation of alpha hydroxy acids with similar skin benefits and fewer irritation responses. Lactobionic acid belongs to this broader family. That makes PHA a sensible first option if you want chemical exfoliation but find stronger exfoliants uncomfortable.1

Exfoliation removes dead cells from the outer skin layer, but sensitive skin does not automatically need it. A mild chemical exfoliator can be preferable to an abrasive scrub, which can be too irritating for sensitive or dry skin.3

Which is better for sensitive skin, PHA or AHA?

The amount of exfoliation an AHA produces depends on its type, concentration, pH and other ingredients. pH measures how acidic or alkaline a formula is. Comparing percentages alone misses part of the picture: two AHA products with the same percentage can differ in how much they exfoliate.2

For consumer glycolic and lactic acid products, safety criteria include an acid concentration of 10 percent or less, a final pH of at least 3.5, and protection against increased sun sensitivity or directions for daily sun protection. Those are safety conditions, not a reason to start sensitive skin at 10 percent. Choose a mild formula rather than treating the highest permitted strength as a target.2

Sensitive skin often stings during or just after cleansing and is more likely to be dry. Repeated sensitivity can also accompany an underlying problem such as eczema or rosacea. If ordinary cleansing already causes discomfort, deciding whether to exfoliate matters more than choosing between two acids.5

How should you use an exfoliant on sensitive skin?

1. 1Check your existing routine. Prescription retinoids, retinol and benzoyl peroxide can make skin more sensitive or cause peeling; adding exfoliation can worsen dryness or breakouts.
2. 2Choose a mild chemical exfoliator and follow its application and rinsing directions. Do not exfoliate skin with open cuts, wounds or sunburn.
3. 3Apply gently, without adding a scrub or vigorous rubbing.
4. 4Follow with moisturizer immediately after exfoliating.
5. 5Adjust frequency to the product and your skin's response. More aggressive exfoliation belongs on a less frequent schedule, not an automatic daily one.

AHA can increase sensitivity to sunlight. Use sunscreen, wear protective clothing and limit sun exposure while using an AHA and for a week after stopping. Applying an AHA only at night does not replace these precautions.2

What results should you expect?

AHAs can improve skin texture and luminosity, and PHA offers similar types of benefits with less irritation. Improving texture is a useful goal; building an alphabet collection in the bathroom is not. There is no universal timetable for a smoother appearance: the acid, formula and skin concern affect the outcome, so follow the individual product's directions rather than increasing use to hurry results.17

Can I use PHA and AHA together?

For sensitive skin, choosing one exfoliant rather than layering separate PHA and AHA products is the more cautious approach. This is general guidance to limit irritation, not a claim that the two acids are chemically incompatible. Higher AHA concentrations and combinations with other skin treatments can increase irritation; follow the directions for a finished formula instead of assembling your own combination.7

When should you stop or get help?

Stop exfoliating if redness or irritation develops. Burning, rash, swelling and blisters are also reported reactions to AHA products and should not be treated as signs of progress. Seek medical advice for these reactions, or if sensitivity keeps returning and you are unsure whether exfoliation is appropriate.23

Avoid strong chemical exfoliation if you have a darker skin tone or develop dark spots after acne, insect bites or burns. Aggressive exfoliation can increase pigmentation, making gentleness especially relevant to the choice.3