How to patch test a new skincare product

A patch test is a small trial of a new product on a small piece of skin before you use it more widely. It is a common step, and the NHS mentions it in its advice on contact dermatitis, a skin reaction to things that touch the skin. A patch test does not guarantee that you will not react later.

What are the usual steps?

1. Wash and dry a small area, such as the inner forearm or behind the ear. Check the product label first, since some give their own directions.
2. Apply a small amount.
3. Leave it for the time the label says. If it gives none, ask a pharmacist.
4. Look for redness, itching, burning, swelling or blisters, and check again over the following day or two.
5. If any of these appear, wash it off and stop. If you only see no change, try a small amount on the real area next.

A rule to use

One new product at a time, a patch first, a gap between products. If you add three things in one week and your skin reacts, you cannot tell which one did it. See also how to read a skincare label.

The exception

Do not patch test and wait if you have had a serious reaction to a product in the past. Ask a doctor first. If you get swelling of the face, lips or tongue, trouble breathing, or a rash that spreads fast, seek urgent medical care.

Patch tests for clinic treatments are done by the practitioner. Ask your clinic whether they do one, as the checklist in skin treatment consultation checklist suggests.

This is general information. Ask a licensed professional about your own skin.