Compare · Ingredients

Lactic Acid vs Polyhydroxy Acids

Lactic Acid: Exfoliates rough skin and contributes to hydration in suitable formulas. Polyhydroxy Acids: Offers exfoliation through ingredients such as gluconolactone and lactobionic acid.

Research updated 2026-10-25

Five lactic acid serums lined up on white, from The Ordinary, Glytone, Paula's Choice and Prequel

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 Lactic Acid if…

Choose for rough, dry texture; sensitive areas may sting.

Dry, rough skin
Keratosis pilaris bumps
You want a gentler AHA than glycolic

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

Alternatives, not combined

Can you use both?

Both are gentle exfoliants. One is usually enough.

At a glance

● Lactic Acid

● Polyhydroxy Acids

Type

Alpha hydroxy acid (AHA)

Polyhydroxy acid (PHA) family

What it does

Exfoliates rough skin and contributes to hydration in suitable formulas.

Offers exfoliation through ingredients such as gluconolactone and lactobionic acid.

Best for

Dull Skin; Dry Skin; Keratosis Pilaris

Acne; Dull Skin; Sensitive Skin

Studied concentrations

8% L-lactic acid cream in a controlled photoaging study; body lotions vary.

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.

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

Can sting cracked skin and aggravate eczema or rosacea flares.

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.

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.

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

Lactic Acid

Polyhydroxy Acids

Moderate evidenceSome supportive research

Dull Skin on light skin.

Dull Skin

A controlled cream trial supports modest improvement in photodamaged texture.

—

Limited evidenceEarly or small studies

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

Suitable acid/lactate formulas may soften dry, rough skin.

The back of an upper arm on light skin, covered in small rough bumps at every hair opening. Each bump sits in a faint pink ring, so the arm looks evenly speckled and slightly red.

Keratosis Pilaris

Keratolytic body lotions may soften rough bumps; responses vary.

Dull Skin on light skin.

Dull Skin

Small studies of PHA formulas suggest smoother surface texture.

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.

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

Extreme close-up of light skin in an active eczema flare, too close to tell which part of the body it is. Blotchy pink-red inflammation covers the whole frame with no clear edge, with small raised bumps, fine dry scale and a few fresh scratch marks.

Eczema

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

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

Rosacea

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.

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.

How it works

Lactic Acid mechanism diagram. Loosens outer skin cells: An acidic formula promotes surface shedding. Contributes to hydration: Lactate is part of the skin's water-binding environment. — Open full-size diagram
Diagram explanation and sources
Loosens outer skin cells: An acidic formula promotes surface shedding. Contributes to hydration: Lactate is part of the skin's water-binding environment.
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

Moisturizer

Step 4

Sunscreen

Night

Step 1

Cleanser

Step 2

Polyhydroxy AcidsMorning or night

Step 3

Lactic AcidNight

Strengths and forms

Concentrations

Lower-strength lactic acid skincare differs from concentrated office peels. Research includes 5–12% leave-on formulas and specialist peel formulations as high as 85–92%.

5–12%

85–92%

Studied leave-on formulas

Studied for texture and signs of skin aging. Body lotions and facial products can have different directions and tolerance.

Specialist peel formulations

Used in small clinician-applied studies. These are research examples, not a home-use range or a routine starting strength.

Choosing a strength: Choose a labeled facial or body product for the area being treated. Professional peel concentrations are a separate category.

Higher strengths: Concentrated lactic acid can cause chemical burns and pigmentation changes. A study of a professional peel does not establish safe home use.

Formula matters: The product’s acidity and buffering matter alongside its percentage. Ammonium lactate lotions are not equivalent to unbuffered acid peels.

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

Serum · Body lotion · Peel

Toner · Serum · Cleanser

When you’ll see results

Approximate windows, not promises.

● Lactic 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

Can sting cracked skin and aggravate eczema or rosacea flares.

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. Avoid actively inflamed or broken skin unless the product is specifically directed for it.

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

Very little is absorbed, but that decision belongs 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 lactic 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. Helps loosen surface cells; lactic acid/lactate also contributes to the skin’s water-binding environment.

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

Lactic Acid

MediCube Red Acne Body Peeling Shot
Paula's Choice Skin Perfecting 6% Mandelic Acid + 2% Lactic Acid

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

Lactic Acid:What should I choose lactic acid for?

Choose for rough, dry texture; sensitive areas may sting.

Lactic Acid:How strong is the evidence?

An older 22-week controlled study supports modest photoaging improvement from 8% cream. It does not establish every body-lotion claim or superiority over glycolic acid.

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