Lactic Acid for Dry Skin: The Gentler AHA That Also Hydrates

Lactic acid suits dry skin because it does two jobs at once: it gently exfoliates the dull, flaky surface layer and it draws water into the skin. Lactate is a natural part of the skin's own moisturizing system, which is why lactic acid usually feels kinder than glycolic acid. Start with 5% to 10%, two or three evenings a week, and wear sunscreen daily.

This guide explains why lactic acid hydrates as well as exfoliates, how it compares with glycolic acid, how often to use a lactic acid serum, how it helps bumpy arms from keratosis pilaris, and when to hold back.

What is lactic acid and why is it good for dry skin?

Lactic acid is an alpha hydroxy acid (AHA), like glycolic acid, with a slightly larger molecule. It loosens the bonds between dead cells on the surface so they shed evenly, which takes away the rough, ashy look dry skin often has. What sets it apart is its link to hydration. A review in Molecules describes lactic acid, as sodium lactate, as a well-known part of the skin's natural moisturizing complex and an excellent moisturizer. That complex, often called natural moisturizing factor or NMF, is the mix of small water-holding molecules inside the outer layer of skin.

DermNet groups alpha hydroxy acids such as lactic acid with glycerin and urea as humectants, ingredients that attract and retain water in the outer layer of skin. A hydroxy-acid review makes the same point more broadly: many preparations that contain hydroxy acids are both exfoliants and moisturizers.

So for skin that's both flaky and tight, lactic acid treats the flakes and helps with the tightness in one step. If you're not sure whether your skin is dry or just thirsty, see dry vs dehydrated skin.

What are the benefits of lactic acid for skin?

The main benefits are smoother texture, less dullness, better hydration and, at higher strengths, firmer-looking skin over months. The best-known study is small but useful. Participants applied 5% or 12% lactic acid twice a day for three months. The 12% group had increased epidermal and dermal firmness and thickness and visible improvement in smoothness and lines. The 5% group showed similar surface and epidermal changes without changes in the deeper dermis.

• Smoother, softer texture as dead cells shed more evenly.
• Brighter-looking skin, since a flat, flaky surface reflects light poorly.
• Better hydration from its humectant action.
• Help with sun damage. In professional peels, a chemical-peel review reports that lactic acid shows comparable efficacy to glycolic acid for photodamage, superficial hyperpigmentation and fine lines.

Lactic acid vs glycolic acid: which is better?

Lactic acid is usually the better first AHA for dry or easily irritated skin, and glycolic acid is usually the stronger choice for oily, sun-damaged skin that tolerates acids well. A 1996 comparison cited in a later review found that lactic acid was less irritating than glycolic acid.

One technical wrinkle: in peels, lactic acid has a lower pKa and so a lower pH than glycolic acid at the same concentration, which is why professionals often use a lower percentage of lactic to reach a similar depth. At home strengths, how your skin feels is the better guide. Our full guide to glycolic acid covers the stronger option, and AHA vs BHA compares acids for oily and clogged skin.

What strength of lactic acid should I use?

For the face, 5% is a sensible start and 10% is a common next step. The Cosmetic Ingredient Review panel considers lactic and glycolic acid products safe for consumers at 10% or less with a pH of 3.5 or higher, with sun-protection directions. Stronger concentrations are peel territory: superficial peels use lactic acid at 10% to 30% in a clinic.

• 5%: first-timers, dry or easily irritated skin. The Ordinary's 5% version is $8.10 for 30 ml as of October 2026.
• 10%: once 5% feels comfortable for several weeks. The Ordinary's 10% serum lists a pH of 3.60 to 3.80.
• 12% body lotions: for rough arms, legs and heels, where skin is thicker. The 12% strength is the one that showed deeper changes in the three-month study.

Note that The Ordinary's own label says not to use its lactic acid serums on sensitive, peeling or compromised skin. "Gentler AHA" still means an acid.

How often should I use a lactic acid serum?

Start two or three evenings a week and build toward once a day only if your skin stays comfortable. The Ordinary's directions say to apply once daily, ideally in the evening, and that you can dilute it with other products until your skin builds tolerance.

1. Patch test on a small area first.
2. Cleanse gently in the evening and pat dry.
3. Apply a few drops to dry skin, avoiding the eye area and any cracked or broken skin.
4. Follow with a moisturizer; for dry skin, a cream with ceramides or glycerin works well.
5. Use broad-spectrum SPF 30 or higher every morning.

On nights you use lactic acid, skip retinoids and other exfoliants until you know how your skin handles each one alone. For dry skin, many people find that two or three nights a week gives most of the benefit with little risk. Our dry skin routine shows where an exfoliant fits.

Does lactic acid help keratosis pilaris?

Yes. Lactic acid is one of the standard ingredients dermatologists suggest for the rough, bumpy skin of keratosis pilaris (KP). The AAD says most moisturizing creams used to treat KP contain urea or lactic acid, and DermNet lists creams with urea, salicylic acid, lactic acid or alpha hydroxy acids to help loosen the plugs of keratin in the follicles.

KP is a very common, harmless condition in which small bumps appear on the arms, thighs or bottom when hair follicles become blocked with keratin. It can't be cured, but it can be smoothed. The AAD's self-care advice:

• Apply a thick cream to damp skin within 5 minutes of bathing, and again two or three times a day.
• Avoid harsh scrubbing, which tends to irritate skin and worsen KP. A soft washcloth is enough.
• If skin turns raw or very dry, pause the exfoliating product for a few days.
• Plan for maintenance. Once bumps improve, many people keep treating a few times a week.

If KP becomes itchy or inflamed, a pharmacist or doctor can advise on next steps.

What are the side effects of lactic acid?

The usual side effects are mild stinging, redness, dryness and greater sensitivity to the sun. DermNet notes that acidic preparations like these often sting if applied to scratched or cracked skin, so let chapped patches heal first.

Sun sensitivity applies to every AHA. In an FDA-described study, four weeks of AHA cream raised sensitivity to UV-induced reddening by 18%; the effect faded within a week of stopping. The FDA's recommended warning is to use sunscreen and limit sun exposure while using the product and for a week afterward. See how much sunscreen to use.

If you're pregnant or breastfeeding, ask your doctor or midwife before starting any new active; we couldn't find a pregnancy-specific statement on topical lactic acid from a major source. People with eczema or rosacea should also check with a dermatologist first.

How can a skin scan or ingredient scanner help?

Dry skin changes slowly and with the weather, so it's easy to give up on lactic acid before it has had time to work. Pori takes a selfie and returns an overall skin score with separate readings for Hydration & Moisture and Pores & Texture, and its progress charts show whether those numbers move over a few weeks of use. Its ingredient scanner (Pro) reads a barcode or label photo and flags each ingredient as beneficial, use with caution or avoid for your skin type, which makes it easier to notice that your toner and your serum both contain acids.

An app looks at appearance, and an app is not a diagnosis. If dryness comes with cracking, intense itch or a rash, see a dermatologist.