Compare · Ingredients

Glycolic Acid vs Lactic Acid

Glycolic Acid: Exfoliates rough skin and can modestly improve signs of sun damage. Lactic Acid: Exfoliates rough skin and contributes to hydration in suitable formulas.

Research updated 2026-10-25

Four glycolic acid toner and liquid bottles lined up on white, one with its box

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

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 Glycolic Acid if…

Choose for rough texture and dullness; start with a mild leave-on formula.

Rough texture or dullness
Mild sun damage
Skin that tolerates acids

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

Alternatives, not combined

Can you use both?

Both are AHAs. Lactic is gentler and more hydrating; one is usually enough.

At a glance

● Glycolic Acid

● Lactic Acid

Type

Alpha hydroxy acid (AHA)

Alpha hydroxy acid (AHA)

What it does

Exfoliates rough skin and can modestly improve signs of sun damage.

Exfoliates rough skin and contributes to hydration in suitable formulas.

Best for

Dull Skin; Wrinkles and Fine Lines; Sun Spots

Dull Skin; Dry Skin; Keratosis Pilaris

Studied concentrations

8% leave-on cream and 50% professional peels in separate trials.

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

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

Stinging, peeling and irritation are possible, particularly on inflamed skin.

Can sting cracked skin and aggravate eczema or rosacea flares.

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

Glycolic Acid

Lactic Acid

Moderate evidenceSome supportive research

Dull Skin on light skin.

Dull Skin

Exfoliation can smooth rough texture and improve the look of dull skin.

A relaxed forehead with faint shallow horizontal fine lines.

Wrinkles and Fine Lines

An 8% cream produced modest improvements in photodamaged skin.

Dull Skin on light skin.

Dull Skin

A controlled cream trial supports modest improvement in photodamaged texture.

Limited evidenceEarly or small studies

AI-generated educational illustration of Sun Spots: 1. Sun Spots Header — Light Skin; Lighter skin. Not a clinical photograph.

Sun Spots

A small professional-peel trial found slight lightening of sun spots.

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.

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.

Insufficient evidence

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

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.

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.

Ice Pick Scars on light skin.

Ice Pick Scars

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.

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.

How it works

Glycolic Acid mechanism diagram. Acts at the outer skin: Acidity helps loosen adhesion between dead cells. Promotes surface shedding: Texture changes depend on pH and the formula. — Open full-size diagram
Diagram explanation and sources
Acts at the outer skin: Acidity helps loosen adhesion between dead cells. Promotes surface shedding: Texture changes depend on pH and the formula.
Schematic illustration; not a measurement of skin penetration. Effects vary with ingredient identity and formulation.
Source 1 · Source 2 · Source 3

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

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

Moisturizer

Step 3

Sunscreen

Night

Step 1

Cleanser

Step 2

Glycolic AcidNight

Step 3

Lactic AcidNight

Strengths and forms

Concentrations

Home skincare and office peels use very different glycolic acid strengths. Clinical studies include 8% leave-on cream and professional peels from 20% to 70%.

8%

20–70%

Studied leave-on cream

Studied for sun-damaged skin. Use a finished home product as labeled; this does not establish a universal ideal percentage.

Professional peeling range

Serial office peels have used these strengths for selected concerns. These are controlled procedures, not home-use targets.

Choosing a strength: Choose a home product for your concern and skin tolerance. Ask a qualified clinician whether an office peel is appropriate.

Higher strengths: High-strength peels can cause burns, scars and lasting color changes. Do not copy a study’s peel concentration or timing at home.

Formula matters: Acidity, neutralization, contact time and layers influence peel depth. Two products with the same percentage can act differently.

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.

Forms

Toner · Serum · Pads · Peel

Serum · Body lotion · Peel

When you’ll see results

Approximate windows, not promises.

● Glycolic Acid

● Lactic Acid

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, peeling and irritation are possible, particularly on inflamed skin.

Can sting cracked skin and aggravate eczema or rosacea flares.

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 through the skin and it is commonly used, but this is not a decision to make from a webpage. Ask the doctor managing your pregnancy.

Very little is absorbed, but that decision belongs with the doctor managing your pregnancy.

How it works

In the skin

On the skin. The finished product delivers glycolic 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. Loosens adhesion between outer skin cells, promoting exfoliation; concentration, pH and contact time matter.

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 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.

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.

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

Molecule size

Glycolic Acid · 76 Da

Lactic Acid · 90 Da

Smaller than 500 Da passes the outer skin more easily. Size isn’t an effectiveness score.

500 Da guideline

Product examples

Glycolic Acid

The INKEY List Glycolic Acid Toner
Paula's Choice 8% AHA Lotion Exfoliant
Paula's Choice RESIST Daily Smoothing Treatment With 5% AHA

Lactic Acid

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

Common questions

Glycolic Acid:What should I choose glycolic acid for?

Choose for rough texture and dullness; start with a mild leave-on formula.

Glycolic Acid:How strong is the evidence?

An older 22-week vehicle-controlled trial supports modest photoaging benefits from 8% cream. Results from 50% peels cannot be transferred to everyday serums.

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.

Sources

Sources and further reading

Dermapedia on YouTube