How to patch test a new skincare product
To patch test, apply a small amount of the product to the inner forearm or behind the ear once a day for three to five days, leaving it on as you normally would. If there is no redness, itching or swelling, try it on a small area of the jaw before using it across the whole face.
Why patch test at all?
Any new product can disagree with your skin, including gentle, well tolerated ones. A patch test tells you on a small area first, rather than across your whole face.
It matters most if you have sensitive skin, have reacted to products before, or are introducing several new products at once.
How do you patch test a serum or moisturiser?
Apply a pea sized amount to the inner forearm or the skin just behind the ear.
Leave it on, and repeat once a day for three to five days.
If all is well, apply to a small patch along the jawline for another two days, then use as normal.
How do you patch test a shampoo or scalp serum?
Apply a little behind the ear or at the nape of the neck, where the scalp meets the neck, for a few days.
For a leave in scalp serum, leave it on. For shampoo, rinse after a couple of minutes as you would in the shower.
What counts as a reaction?
Redness that does not fade, itching, swelling, bumps or a burning feeling. Stop using the product and rinse the area.
Mild, brief tingling as a product absorbs is different and usually settles. If you are unsure, stop, and ask a pharmacist or your doctor.
Common questions
How long should a patch test last?
Three to five days of daily application on the forearm or behind the ear, then a couple of days on a small area of the face.
Can a product pass a patch test and still irritate my face?
Occasionally, because facial skin is thinner. That is why the second, small facial test on the jawline is worth doing.
Should I patch test every product?
It is sensible for anything new, and especially important if you have reacted to skincare before or have very sensitive skin.
Related guides
- Copper peptide side effects: what to expect
- How to use copper peptides: order, timing and routine
- Copper peptides with AHA and BHA exfoliants
Cosmetic products for external use only. Copper peptide products support the appearance of skin and hair. They are cosmetics, not medicines.