Polyhydroxy Acids
Offers exfoliation through ingredients such as gluconolactone and lactobionic acid.
Key facts
Polyhydroxy Acids at a glance.
Helps with
Roughness and dullness
Results
Assess at 8–12 weeks
Skin tolerance
Can still irritate
Routine fit
Start a few evenings weekly
At a glance
Top things to know about Polyhydroxy Acids
- What it is. Polyhydroxy acid (PHA) family.
- What it does. Offers exfoliation through ingredients such as gluconolactone and lactobionic acid.
- What limits the claim. A 150-person trial tested 14% gluconolactone for acne. Evidence from that molecule or a mixed-acid serum does not establish identical effects for all PHAs.
- Choosing a formula. Choose for mild exfoliation when stronger acids are uncomfortable; tolerance still varies.
More details: strength, timing and precautions
| Bottom line | Choose for mild exfoliation when stronger acids are uncomfortable; tolerance still varies. |
|---|---|
| Type | Polyhydroxy acid (PHA) family |
| What it does | Offers exfoliation through ingredients such as gluconolactone and lactobionic acid. |
| Best for | Acne; Dull Skin; Sensitive Skin |
| Studied concentrations | 14% gluconolactone in an acne trial; newer studies test mixed-acid formulas. |
| When to use | Start on a few evenings weekly; increase only if comfortable. |
| Time to results | Often 8–12 weeks in small cosmetic studies; results may be subtle |
| Irritation | Can still sting or cause a rash; sensitive skin does not guarantee tolerance. |
| Sensitive skin | Choose a simple formula and test a small area first. Avoid actively inflamed or broken skin unless the product is specifically directed for it. |
| Available | Cosmetic or OTC products; some high-strength procedures are separate treatments. |
Often used for
What Polyhydroxy Acids is used for
Acne
One controlled trial found fewer lesions with 14% gluconolactone.
Dull Skin
Small studies of PHA formulas suggest smoother surface texture.
Sensitive Skin
Some tested formulas were well tolerated; this is not proof that all PHAs suit reactive skin.
Dry Skin
The reviewed sources do not establish this ingredient as a treatment for this concern.
Melasma
The reviewed sources do not establish this ingredient as a treatment for this concern.
Acne Scarring
The reviewed sources do not establish this ingredient as a treatment for this concern.
HOW IT WORKS
How Polyhydroxy Acids works
Diagram explanation and sources
Loosens surface cells: PHAs promote shedding in the outer skin. Helps bind water: Hydroxyl groups contribute to water binding.
Schematic illustration; not a measurement of skin penetration. Effects vary with ingredient identity and formulation.
Types
Types of Polyhydroxy Acids
Gluconolactone
A common polyhydroxy acid, or PHA, found in exfoliating skincare.
Lactobionic acid
A related bionic acid often grouped with PHAs. It is a distinct ingredient, not a brand of gluconolactone.
PHA blends
A product may combine these acids. The ingredient mix and finished formula matter; the PHA label does not guarantee that a product will be irritation-free.
Strengths
Polyhydroxy Acids strengths
PHA is a family name, not one ingredient or one standard strength. A clinical acne trial used 14% gluconolactone; that result cannot be transferred directly to lactobionic acid or mixed-PHA products.
14%
An older controlled acne trial tested this specific formula. It does not establish the best percentage for all PHA skincare.
Choosing a strength: Check which PHA is listed, whether the product stays on or washes off, and whether it also contains other exfoliating acids.
Higher strengths: A PHA product can still irritate, particularly when combined with other acids. A high total-acid percentage is not a validated benefit rating.
Formula matters: The individual acid, acidity and base formula matter. A blended-acid percentage does not reveal the amount of each PHA.
Forms
Polyhydroxy Acids forms
Toner
A watery liquid that spreads easily and layers lightly. Alcohol, fragrance and other ingredients influence stinging or dryness.
Serum
A light liquid or gel that spreads in a thin layer. Can suit layering; it may not provide enough moisture on its own.
Cleanser
A cleansing base that lifts surface oil and residue before rinsing. Lather does not by itself indicate how drying it will feel.
Products
Product examples
Isntree Hyper Acid 4 AHA BHA PHA LHA 30 Serum
NeoStrata Ultra Moisturizing Face Cream
Gold Bond Ultimate Pedi Smooth Foot Cream
How to use it
When to use
Start on a few evenings weekly; increase only if comfortable.
How to apply
Apply a thin layer to clean skin using the amount on the product label.
Moisturizing
Use a simple moisturizer if needed; for rich oils or balms, start with a small amount.
Tolerance
Can still sting or cause a rash; sensitive skin does not guarantee tolerance.
If it is not working
Reassess after roughly 8–12 weeks, or sooner for worsening symptoms. Persistent pigment, acne or a rash may need a different treatment.
Sun protection
Use broad-spectrum SPF 30 or higher each morning, especially when treating uneven pigmentation.
What to expect
First few weeks
Assess tolerance and texture; immediate softness can come from the base formula.
4–8 weeks
Subtle changes may appear in some tested products; evidence varies.
8–12 weeks
Compare photographs in the same lighting and reassess benefit.
3–6 months
Photoaging trials often need several months; expect modest rather than dramatic change.
6–12 months
Long-term evidence is limited for many cosmetic actives; continue only if useful.
What it pairs with
| Ingredient | Use | What to know |
|---|---|---|
| Moisturizer | As needed | Choose a simple formula that improves comfort. |
| Sunscreen | Each morning | Use a tested broad-spectrum product; do not mix other skincare into it. |
| Other active treatments | Introduce separately | Compatibility does not prove an added benefit. Seek a treatment plan when combining medicines. |
Alternatives
Alternatives
Glycolic acid
Considerably faster and better studied, and much more likely to sting and to increase sun sensitivity.
Lactic acid
Also hydrating and reasonably gentle, but stronger and faster than a PHA, and it does increase sun sensitivity.
Mandelic acid
The gentle end of the AHA family, and the natural step up from a PHA when you want more effect.
Salicylic acid
Gets inside the pore, which a PHA does not, so it is the better choice for blackheads and acne.
Azelaic acid
Gentle and suitable for rosacea, and it treats acne and dark marks rather than exfoliating.
Niacinamide
Not an exfoliant at all, but a common companion for sensitive skin working on tone and barrier at the same time.
Plain moisturizer
For comfort, none for exfoliation. If comfort is all you need, a PHA is not required.
Safety and cautions
Common reactions
Can still sting or cause a rash; sensitive skin does not guarantee tolerance.
When to stop
Stop for persistent burning, swelling, blistering or a new rash. Seek urgent care for breathing difficulty or a severe allergic reaction.
Sensitive or inflamed skin
Choose a simple formula and test a small area first. Avoid actively inflamed or broken skin unless the product is specifically directed for it.
Important limits
Do not use a cosmetic product as a substitute for diagnosis of an unexplained, changing or persistent skin problem.
Pregnancy
Not stated in existing content
Questions
Questions you might be asking.
What should I choose polyhydroxy acids for?
Choose for mild exfoliation when stronger acids are uncomfortable; tolerance still varies.
How strong is the evidence?
A 150-person trial tested 14% gluconolactone for acne. Evidence from that molecule or a mixed-acid serum does not establish identical effects for all PHAs.
Sources
Sources and further reading
Research updated 2026-10-25. Evidence grades reflect confidence in a specific benefit, not its size.
Related
Keep exploring.
Mandelic Acid
Lactic Acid
Glycolic Acid
Azelaic Acid
Salicylic Acid
Melasma
Niacinamide
Dry Skin
Acne Scarring
Azelaic Acid vs Polyhydroxy Acids
Glycolic Acid vs Polyhydroxy Acids