Skin safety guide
How to Patch Test Skincare Safely
A patch test is a simple 48-hour check that helps you spot a possible reaction before applying a new product to your face. Here is exactly how to do one, the UK-recommended way.
What is a patch test?
A patch test means applying a small amount of a new skincare product to a discreet area of skin and waiting to see how your skin responds before using it as directed. It is the simplest way to reduce the risk of an unexpected reaction — particularly with active, medical-grade formulas such as retinoids, exfoliating acids and vitamin C.
Why it matters
Even excellent products can disagree with individual skin. Reactions range from mild redness or tingling to contact dermatitis — an itchy, inflamed response the NHS describes as common with cosmetics and toiletries. A 48-hour patch test catches most of these responses on a small, hidden area instead of your whole face.
Active ingredients such as retinol also cause an expected adjustment period (mild dryness or flaking). A patch test helps you tell the difference between normal adjustment and a true reaction.
Who should patch test?
Everyone starting a new product — but especially if you:
- Have sensitive, reactive or allergy-prone skin
- Have a history of eczema, rosacea or contact dermatitis
- Are starting a retinoid, exfoliating acid (AHA/BHA) or high-strength vitamin C for the first time
- Are using several new products at once (test them one at a time)
If you are pregnant, breastfeeding, or under the care of a dermatologist, check with a healthcare professional before starting new active skincare.
How to patch test — step by step
Choose your test spot
Pick a small, discreet area of skin — behind the ear or the inner forearm are ideal. Make sure the skin is clean, dry and unbroken.
Apply a small amount
Apply a pea-sized amount of the product to the test area, as it would normally be used. For rinse-off products (cleansers, masks), apply, leave for the time stated on the pack, then rinse.
Wait 48 hours
Leave the area undisturbed and keep it dry where possible. Do not apply other new products to the same spot during the test. Repeat the application once or twice daily for leave-on products if your skin is sensitive.
Check the skin
Look at the area in good light after 24 and 48 hours. You are checking for redness, itching, burning, swelling, bumps or flaking beyond mild, brief tingling.
All clear? Start slowly
If there is no reaction after 48 hours, begin normal use following the product directions — introducing strong actives gradually, such as every other night for retinoids.
What to look out for
Stop using the product and rinse the area if you notice any of the following during the test period:
- Redness that persists or spreads
- Itching, burning or stinging that does not settle within a few minutes
- Swelling, bumps, hives or blistering
- Flaking, weeping or broken skin at the test site
If a reaction is severe, spreads beyond the test area, or involves facial swelling or difficulty breathing, seek urgent medical advice (call NHS 111, or 999 in an emergency).
When not to use a product
Do not apply new active skincare to broken, sunburnt or infected skin, immediately after professional treatments (peels, laser, microneedling) unless advised by your practitioner, or alongside prescription treatments without professional guidance. If your patch test produced any reaction, do not use the product — contact us and we will help you find a suitable alternative.
No reaction? You're good to go
If the test area looks and feels normal after 48 hours, begin using the product as directed. Introduce strong actives gradually — for example, retinoids every other night for the first two weeks — and always follow the usage guidance on the product page and packaging.
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