How to patch test, step by step
Three days of patience before a new product goes on your whole face.
By the Fogline team · March 9, 2026 · 3 min read
Even gentle, fragrance-free products can disagree with someone. A patch test is a simple way to lower the odds of a reaction on your whole face. It does not rule one out, but it helps.
The steps
- Pick a small spot: behind the ear, the side of the neck or the inner forearm.
- Apply a small amount the way you would normally use the product.
- Repeat once a day for three days, leaving it on as you normally would.
- Watch for redness, itching, burning or swelling.
- If anything appears, wash it off and stop using it. If nothing does, try it on your face.
When to talk to a professional
If you have a skin condition, a history of strong reactions, or a reaction that does not settle within a day or two, talk to a pharmacist, doctor or dermatologist. Skincare can help skin feel and look better, but it is not a treatment for skin conditions.
This article is general information about skincare, not medical advice. If you have a skin condition or a reaction that does not settle, please talk to a pharmacist, doctor or dermatologist.
