How to patch test a new product
Patch testing is the simple habit of trying a new skincare product on a small, hidden area of skin before applying it to your face. It takes two minutes and can save you from days of irritation.
Your face is more reactive than the skin on your body — it's thinner, more exposed, and often already dealing with multiple products. A quick arm test gives you early warning.
Choose your spot
The inner forearm or behind the ear are ideal. These areas are sensitive enough to show a reaction, but discreet enough that no one will notice if something does flare up.
Apply a small amount
Use roughly the size of a pea. Don't rub it in fully — just a thin layer is enough. You're testing for a reaction, not moisturising your arm.
Wait 24–48 hours
Leave the product on and go about your day. Don't wash the area more than usual. Patience here is the whole point — some reactions take time to appear.
Check for signs
Look for redness, itching, burning, swelling, or small bumps. If any of these show up, wash the area with water and do not use the product on your face.
What to do if you react
If you notice any redness, itching, burning, or swelling during your patch test, wash the area immediately with cool water and stop using the product. Do not apply it to your face.
If the reaction is severe (significant swelling, blistering, or spreading redness), seek medical advice. If you bought the product through a Skinsight recommendation, email us at support@skinsight.clinic and we'll help you find a suitable alternative.
Products to always patch test
- Retinoids and retinol
- Acids (AHAs, BHAs, PHAs)
- Vitamin C serums
- New moisturisers or cleansers
- Any product with fragrance or essential oils
- Exfoliating treatments or peels
Tip: Introduce one new product at a time. If you start three new products in one week and your skin reacts, you'll have no idea which one caused it. One product, one patch test, one week — that's the safest way to build a routine.