Compare · Ingredients

Azelaic Acid vs Polyhydroxy Acids

Azelaic Acid: Treats acne and rosacea bumps; may also help uneven pigmentation. Polyhydroxy Acids: Offers exfoliation through ingredients such as gluconolactone and lactobionic acid.

Research updated 2026-10-25

Five azelaic acid tubes and bottles on white, most marked 10 percent, from Peach Slices, Paula's Choice, Facetheory, The Ordinary and Naturium

Five PHA toner and serum bottles lined up on white with clear liquid swatches beside them

Which one?At a glance What it helps Diagrams Using both Strengths Results Safety How it works Products Questions

Which one is right for you?

Choose Azelaic Acid if…

Choose for acne or rosacea bumps, especially when uneven tone is also a concern.

Acne or rosacea bumps
Dark marks after spots
Pregnancy, where many alternatives are off the table

Choose Polyhydroxy Acids if…

Choose for mild exfoliation when stronger acids are uncomfortable; tolerance still varies.

Sensitive skin that stings with AHAs
Mild dullness or texture
Gentle exfoliation

Fine together

Can you use both?

PHAs are very gentle exfoliants and suit sensitive skin alongside azelaic acid. Alternate if stinging occurs.

At a glance

● Azelaic Acid

● Polyhydroxy Acids

Type

Anti-inflammatory and pigment-targeting acid

Polyhydroxy acid (PHA) family

What it does

Treats acne and rosacea bumps; may also help uneven pigmentation.

Offers exfoliation through ingredients such as gluconolactone and lactobionic acid.

Best for

Rosacea; Acne; Post-Inflammatory Hyperpigmentation

Acne; Dull Skin; Sensitive Skin

Studied concentrations

15% gel for rosacea in vehicle-controlled trials; 20% creams are also used clinically.

14% gluconolactone in an acne trial; newer studies test mixed-acid formulas.

When to use

Morning or night, as directed by the finished product.

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

Often 8–12 weeks in small cosmetic studies; results may be subtle

Irritation

Stinging, itching and dryness can occur; reduce use for persistent 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. Individual tolerance matters more than an ingredient’s reputation for being gentle.

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

Prescription or cosmetic status depends on the active, formula and country; check the label.

Cosmetic or OTC products; some high-strength procedures are separate treatments.

What it helps

Compare uses by strength of evidence. Evidence level describes confidence in a benefit, not its size.

Evidence level

Azelaic Acid

Polyhydroxy Acids

Strong evidenceMost established uses

Redness and fine superficial vessels across a light-skinned cheek and nose.

Rosacea

Two large trials support 15% gel for inflammatory bumps, with some erythema improvement.

—

Moderate evidenceSome supportive research

Inflamed acne on light skin. The spots sit in a patch of pink, and the ring of redness around each one is easy to see. A few have a yellow-white head, and the skin between them is dry and flaking.

Acne

A guideline-supported topical option; evidence depends on the strength and formula.

—

Limited evidenceEarly or small studies

Flat light-brown residual marks on a fair cheek.

Post-Inflammatory Hyperpigmentation

May help acne-related pigment; the reviewed rosacea trials did not measure this benefit.

Inflamed acne on light skin. The spots sit in a patch of pink, and the ring of redness around each one is easy to see. A few have a yellow-white head, and the skin between them is dry and flaking.

Acne

One controlled trial found fewer lesions with 14% gluconolactone.

Dull Skin on light skin.

Dull Skin

Small studies of PHA formulas suggest smoother surface texture.

Sensitive Skin on light skin.

Sensitive Skin

Some tested formulas were well tolerated; this is not proof that all PHAs suit reactive skin.

Insufficient evidence

Flat tan patches with soft irregular edges across the forehead and upper cheek of an adult with light skin, the surface completely smooth.

Melasma

The cited rosacea trials and acne guideline do not establish melasma clearance.

A relaxed forehead with pronounced deep horizontal furrows.

Deep Wrinkles

The reviewed sources do not establish this ingredient as a treatment for this concern.

Acne scarring on light skin. Small sharply cut pits and broad shallow dips across a cheek, several sitting inside faint flat pink marks, with no active spots.

Acne Scarring

The reviewed sources do not establish this ingredient as a treatment for this concern.

Flat tan patches with soft irregular edges across the forehead and upper cheek of an adult with light skin, the surface completely smooth.

Melasma

The reviewed sources do not establish this ingredient as a treatment for this concern.

Acne scarring on light skin. Small sharply cut pits and broad shallow dips across a cheek, several sitting inside faint flat pink marks, with no active spots.

Acne Scarring

The reviewed sources do not establish this ingredient as a treatment for this concern.

The front of one shin on pale skin. The surface is pink with fine white flaking and a few shallow cracks, and the skin around it is even in tone.

Dry Skin

The reviewed sources do not establish this ingredient as a treatment for this concern.

How it works

Azelaic Acid mechanism diagram. Helps calm inflammation: Acts on pathways involved in acne and rosacea. Affects pigment production: Tyrosinase-related activity may help dark marks. — Open full-size diagram
Diagram explanation and sources
Helps calm inflammation: Acts on pathways involved in acne and rosacea. Affects pigment production: Tyrosinase-related activity may help dark marks.
Schematic illustration; not a measurement of skin penetration. Effects vary with ingredient identity and formulation.
Source 1 · Source 2

Polyhydroxy Acids mechanism diagram. Loosens surface cells: PHAs promote shedding in the outer skin. Helps bind water: Hydroxyl groups contribute to water binding. — Open full-size diagram
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.
Source 1 · Source 2 · Source 3

Using both in one routine

Built from where each one usually sits in a routine. Introduce one at a time.

Morning

Step 1

Cleanser

Step 2

Polyhydroxy AcidsMorning or night

Step 3

Azelaic AcidMorning or night

Step 4

Moisturizer

Step 5

Sunscreen

Night

Step 1

Cleanser

Step 2

Polyhydroxy AcidsMorning or night

Step 3

Azelaic AcidMorning or night

Step 4

Moisturizer

Strengths and forms

Concentrations

Azelaic acid strength should be read together with the product’s indication. Prescription examples include 15% gel for inflammatory rosacea and 20% cream for acne.

15%

20%

Prescription rosacea formulation

Gel formulations are labeled for inflammatory papules and pustules of rosacea. They are not simply a weaker version of a 20% acne cream.

Prescription acne cream

A cream strength used for acne. The cream base and indication differ from the 15% rosacea gel.

Choosing a strength: Choose by the concern and finished product. Cosmetic azelaic acid products are not automatically equivalent to prescription formulations.

Higher strengths: Stinging and irritation can limit use. A larger number does not prove better delivery or better results for a different diagnosis.

Formula matters: Gel, foam and cream vehicles affect delivery and tolerability. Do not compare their percentages as if they were identical formulations.

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%

Studied gluconolactone lotion

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

Cream · Gel · Foam

Toner · Serum · Cleanser

When you’ll see results

Approximate windows, not promises.

● Azelaic Acid

● Polyhydroxy Acids

First few weeks

First few weeksAssess tolerance and texture; immediate softness can come from the base formula.

First few weeksAssess tolerance and texture; immediate softness can come from the base formula.

4–8 weeks

4–8 weeksSubtle changes may appear in some tested products; evidence varies.

4–8 weeksSubtle changes may appear in some tested products; evidence varies.

8–12 weeks

8–12 weeksCompare photographs in the same lighting and reassess benefit.

8–12 weeksCompare photographs in the same lighting and reassess benefit.

3–6 months

3–6 monthsPhotoaging trials often need several months; expect modest rather than dramatic change.

3–6 monthsPhotoaging trials often need several months; expect modest rather than dramatic change.

6–12 months

6–12 monthsLong-term evidence is limited for many cosmetic actives; continue only if useful.

6–12 monthsLong-term evidence is limited for many cosmetic actives; continue only if useful.

Safety and sensitive skin

Common reactions

Stinging, itching and dryness can occur; reduce use for persistent irritation.

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.

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. Individual tolerance matters more than an ingredient’s reputation for being gentle.

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.

Do not use a cosmetic product as a substitute for diagnosis of an unexplained, changing or persistent skin problem.

Pregnancy

It is the usual first choice. Very little is absorbed through the skin, it has a long record, and it is what dermatologists switch people to when retinoids stop. Confirm with the doctor managing your pregnancy.

Low-strength leave-on acids are generally considered acceptable; ask the clinician managing your pregnancy.

How it works

In the skin

On the skin. The finished product delivers azelaic acid in a particular vehicle.

Entering skin. Below the 500 Da guideline; delivery still depends on the formula, solubility, stability and skin condition. Size does not prove effectiveness or penetration depth.

Conversion. No activation step is established as necessary for its intended topical role.

Skin response. Acts on inflammation, acne-related bacteria and pigment pathways; it is not simply an exfoliating peel.

Additional effects. Proposed pathways do not establish a measured depth of delivery or clinical benefit beyond the studies cited.

On the skin. The finished product delivers polyhydroxy acids in a particular vehicle.

Entering skin. No single molecular mass. The 500 Da guideline cannot be applied to this whole ingredient family or mixture.

Conversion. No activation step is established as necessary for its intended topical role.

Skin response. PHA ingredients promote surface exfoliation and may also bind water; individual acids and formulas differ.

Additional effects. Proposed pathways do not establish a measured depth of delivery or clinical benefit beyond the studies cited.

Getting in

Below the 500 Da guideline; delivery still depends on the formula, solubility, stability and skin condition. Size does not prove effectiveness or penetration depth.

No single molecular mass. The 500 Da guideline cannot be applied to this whole ingredient family or mixture.

Product examples

Azelaic Acid

Anua Azelaic Acid 3 Cica Skin Clarifying Toner

Polyhydroxy Acids

Isntree Hyper Acid 4 AHA BHA PHA LHA 30 Serum
NeoStrata Ultra Moisturizing Face Cream
Gold Bond Ultimate Pedi Smooth Foot Cream

Common questions

Azelaic Acid:What should I choose azelaic acid for?

Choose for acne or rosacea bumps, especially when uneven tone is also a concern.

Azelaic Acid:How strong is the evidence?

Two large vehicle-controlled trials support 15% gel for papulopustular rosacea. Acne has guideline support, but a 10% cosmetic serum should not be assumed equivalent to a studied prescription formula.

Polyhydroxy Acids:What should I choose polyhydroxy acids for?

Choose for mild exfoliation when stronger acids are uncomfortable; tolerance still varies.

Polyhydroxy Acids: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

Dermapedia on YouTube