Colloidal oatmeal

What it is

Colloidal oatmeal is whole oat kernels milled so finely that the powder stays suspended in water instead of sinking. It is a mix of starches and beta-glucans that hold water and form a protective film, oat lipids that soften, and polyphenols called avenanthramides that calm inflammation and itch in laboratory and animal tests⁴. In the United States, products containing at least 0.007% colloidal oatmeal can legally be labelled as skin protectants for minor irritation and itching¹.

What the evidence says

Evidence: moderate for eczema itch and dryness; limited for rosacea, where there are no good trials. Oats have centuries of use, FDA recognition as a skin protectant, and several small modern trials showing less itch and dryness, including in children with eczema.

Oat extracts reduce inflammatory signalling in skin cells, and in a study of 29 women with dry, itchy legs a colloidal oatmeal lotion improved dryness, scaling, roughness and itch². In a randomised trial of 49 Black and African American children aged 2 to 15 with mild to moderate eczema, an over-the-counter 1% colloidal oatmeal cream improved eczema scores as much as a prescription barrier cream over three weeks, with gains visible from week one³. These are small, short and often manufacturer-funded studies, so moderate is as far as we will go, but the direction is consistent and the risk is low. Oatmeal does not treat the immune side of eczema; it is a comfort and barrier measure that sits alongside, not instead of, the treatment your doctor prescribes. Our guide to eczema and dry, itchy skin explains the full approach.

How people use it

• A bath: stir colloidal oatmeal (or plain oats blended to a fine flour) into lukewarm water, soak for 10 to 15 minutes, pat dry and moisturise straight away.
• A cream or lotion with colloidal oatmeal as the active ingredient, applied as often as needed, including after bathing and before bed.
• A cool oat compress on itchy patches.
• It suits sensitive, reactive skin as a gentle cleanser or mask.

Cautions

• Oat allergy is uncommon in general, but a French study of 302 children with eczema found oat sensitisation in roughly one in seven, and it was far more common among those who had used oat-containing creams⁵. Ask a doctor before using oat products on an infant with eczema.
• Patch test on the inner arm, especially if you have a diagnosed grain allergy.
• It does not replace prescribed eczema treatment. Never stop a steroid cream or other prescription without talking to the prescriber.
• Weeping, crusted or rapidly spreading eczema needs assessment; see when to see a dermatologist.