Azelaic acid gel, cream, foam or serum: which one?

Azelaic acid comes in four forms: a gel, a foam, a cream and the serums sold in stores. The first three are prescription medicines in the U.S., each approved by the FDA for a specific condition. The 15% gel and 15% foam are approved for rosacea, and the 20% cream for acne. Serums carry no FDA approval, vary from brand to brand, and have little research behind them. This guide compares the forms, how much of each to use, and where azelaic acid goes in a routine. For the ingredient itself, see what azelaic acid is, and for the numbers on the label, see azelaic acid strengths.

The forms at a glance

Form	Strength	FDA-approved for	What the label says about the base	Most common reactions in its trials
Gel	15%	Rosacea bumps	"An aqueous gel," meaning a water-based gel	Burning, stinging or tingling 29%; itching 11%
Foam	15%	Rosacea bumps	An oil-in-water emulsion in a pressurized can	Skin pain (burning, stinging, tenderness) 6.2%
Cream	20%	Mild to moderate acne	A cream with glycerin and other cream ingredients	Itching, burning, stinging, tingling 1% to 5%
Serum	Usually lower than prescription strengths	Nothing; sold as skin care	Varies by product	No label data

The side effect rates come from different trials of different people, so they cannot be compared directly. The gel label says so itself: rates from one drug's trials "cannot be directly compared to rates in the clinical trials of another drug." What the rates do show is that stinging is common with the gel, and the gel label expects it mostly in the first weeks.

Gel or cream

The gel and cream are approved for different conditions, so the condition usually decides. MedlinePlus, the U.S. National Library of Medicine's drug guide, sums it up: "Azelaic acid gel and foam is used to clear the bumps, lesions, and swelling caused by rosacea," and "azelaic acid cream is used to treat the pimples and swelling caused by acne."

The base also changes how much azelaic acid gets into the skin. A 2024 review in Clinical, Cosmetic and Investigational Dermatology says that after one application of a cream, 3% to 5% of the dose stays in the top layer of skin, and that "when using a gel formulation, the percutaneous absorption rate can increase to 8%." Percutaneous absorption means the amount that passes through the skin. The same review says that "while higher concentrations can enhance skin absorption, they also increase the risk of side effects."

A 2019 review in the British Journal of Dermatology lists all three prescription forms, the 15% gel, 20% cream and 15% foam, and found high-certainty evidence that topical azelaic acid reduces rosacea bumps.

Foam

The foam is approved for rosacea only. Its label asks you to shake the can, use "the smallest amount of foam necessary to adequately cover the affected area(s) with a thin layer," and apply it to the whole face: cheeks, chin, forehead and nose.

Two practical points come from the label:

• It is flammable. The label says the propellant in the can is flammable, so avoid fire, flames and smoking during and right after applying it, and do not store the can above 49°C (120°F).
• It has a short life once opened. The label says to throw it away 8 weeks after opening.

A 2017 review in the Journal of Clinical and Aesthetic Dermatology compared the 15% gel and 15% foam, with a focus on how the base affects stinging and other skin sensations. If the gel stings too much, ask your prescriber whether the foam is an option.

How the gel and foam did in their trials

Both rosacea forms were tested against the same product without the medicine, in 12-week trials:

Form	Trial size	Result with azelaic acid	Result without it
15% gel	664 adults in two trials	61% and 61% rated clear, minimal or mild	40% and 48%
15% foam	1,362 adults in two trials	32.1% and 43.4% rated clear or almost clear	23.4% and 32.5%

The two trials used different rating scales, so the numbers show that each form beat its own comparison. They cannot rank the gel against the foam.

Face or body

The gel label says to apply it "into the affected areas on the face," and the foam label names the cheeks, chin, forehead and nose. The cream label says "affected areas" without naming the face. For chest and back acne, a 2020 case series described four women treated with azelaic acid 15% foam and tretinoin 0.05% lotion. A case series follows a few patients with no comparison group, so ask a doctor before treating large areas of the body.

Serums

Serums are sold without a prescription. The 2024 review says "the concentration of AZA used in cosmetic products is typically lower and often combined with other ingredients." So a serum's label may list many ingredients besides azelaic acid. The review adds that some 15% and 20% skin care products are also sold, so a store product can match a prescription strength on its label while carrying no FDA approval.

Serums have little research behind them. A 2021 trial in Pharmaceutics tested a special 10% hydrogel, built with tiny azelaic acid crystals to help it enter the skin, and found it worked as well as 20% cream for acne over 8 weeks. That hydrogel is a research formula. Ordinary store serums were not part of that trial, and no study Skinli found compared a store serum with a prescription product.

If you choose a serum, three checks help:

1. Look for the percentage. A product that does not state it gives you no way to compare.
2. Check what else is in it. The prescription labels ask users to avoid "peeling agents," so a serum that also contains a peeling acid combines two things the labels keep apart. The guide to whether azelaic acid is an exfoliant explains the difference.
3. Start slowly and patch test. Test it on a small area before using it on the whole face. The guide to patch testing explains how.

How much to use

Every prescription label asks for a thin layer:

• Cream: "a thin film" massaged gently into the affected areas.
• Gel: "a thin layer" massaged gently into the affected areas of the face.
• Foam: "the smallest amount" needed to cover the area with a thin layer.

MedlinePlus adds that you should use azelaic acid exactly as directed, and no more often than your doctor prescribes. Skinli's plan uses a pea-sized amount of 10% cream for the face.

Where it goes in a routine

The labels give three rules for timing:

1. Wash with a mild soap or soapless cleanser and pat the skin dry before applying.
2. Wash your hands right after.
3. "Cosmetics may be applied after the application of azelaic acid gel has dried," the gel label says, and the foam label says the same.

The labels give no order for moisturizer. Skinli's 12-week plan, for people with flat acne marks, puts products on in this order each morning: gentle cleanser, moisturizer, azelaic acid 10% cream from week 5, then sunscreen. The acne gels, adapalene 0.1% and benzoyl peroxide 2.5%, go on at night. The free Skinli acne plan sets this up from a photo.

If you also use niacinamide, the guide to azelaic acid with niacinamide covers that pair.

What to avoid with every form

The labels share the same list:

• Alcohol-based cleansers and tinctures, astringents, abrasive scrubs and peeling agents.
• Bandages or wraps over the treated skin.
• Contact with the eyes, mouth and the moist skin inside the nose and mouth.

The American Academy of Dermatology says a rosacea plan also includes "a gentle cleanser, moisturizer, and sunscreen."

Storing it

MedlinePlus says to store azelaic acid at room temperature, away from heat and moisture, and to "dispose of the gel pump and the foam 8 weeks after opening the container." The cream label says to protect it from freezing and store the tube on its side. Check the expiry date on any store product.

When to ask a doctor

Ask a doctor or pharmacist which form suits you if you have rosacea, if your acne is moderate or worse, or if a store product stings for more than the first few weeks. Stop and get help if your face swells or you have trouble breathing after applying it. The guide to azelaic acid for rosacea covers the approved rosacea forms in detail. Skinli gives general education. A doctor is the right person to diagnose and treat your skin.