PHA or AHA: Which Acids Can Sensitive Skin Handle?
There are acids that don't sting — their molecules are simply too big to rush.
PHAs are the same exfoliating acids but with a large molecule: it penetrates slowly and shallowly, so it doesn't sting or irritate. The effect is gentler and slower than AHAs — but it's available even to skin with rosacea.
"Acids aren't for me — everything stings and turns red," says sensitive skin, and goes without exfoliation entirely. Meanwhile, chemists built acids specifically for it long ago — the letters on the box just got less hype.
How it works
The whole difference is molecule size.
AHAs (glycolic, lactic) are sprinters: tiny molecules that penetrate fast and deep, working powerfully. Hence both the results and the price: tingling, possible redness, mandatory adjustment. Glycolic is the smallest and sharpest of them.
PHAs (gluconolactone, lactobionic acid) are steady marathoners: molecules several times larger, seeping into skin slowly and staying in the upper layers. The exfoliation comes out delicate — no burning and almost no photosensitivity. Bonuses AHAs don't offer: PHAs attract moisture (working as humectants) and have antioxidant properties. Essentially an acid and skincare in one molecule.
The price of gentleness is predictable: against strong pigmentation and deep texture, PHAs move slower — where glycolic delivers in a month, gluconolactone needs two or three.
Look for in the list: Gluconolactone, Lactobionic Acid — PHAs; Glycolic Acid, Lactic Acid — AHAs. The transition hybrid is mandelic acid (Mandelic Acid): formally an AHA, but with a large molecule.
Don't mix: with retinol or other acids on the same evening — even PHA gentleness is no reason to stack irritants.
Choose PHA if
- your skin is sensitive, thin, with visible capillaries or rosacea;
- you tried AHAs and got burning and redness;
- you need acids alongside retinol in your routine (on alternate days).
Choose AHA if
- your skin is resilient and the tasks are serious: pigmentation, post-acne, texture;
- you want results faster;
- adjustment and SPF are already routine.
Common mistake. Deciding a "gentle acid" means daily use from day one, no SPF. PHAs are more forgiving, but the rules stand: gradual introduction and sunscreen. Gentle doesn't mean anything-goes.
Fun fact: gluconolactone is no stranger to your body — it's a glucose derivative that takes part in your own metabolism. Perhaps that's why skin greets it so calmly.
Informational only, not medical advice. AI can make mistakes.