On this page 7 sections
A patch test is a simple way to see how your skin responds to a new product before you use it on your whole face. It takes a minute to set up, then a day of waiting. It will not catch every reaction, but it can save you from an uncomfortable surprise.
Why patch test
Any product can bother some skin, even a gentle one. Fragrance, exfoliating acids, retinol, vitamin C, and certain plant extracts are ingredients that some people find irritating. Testing on a small area lets you spot an obvious reaction where it is easy to manage and out of sight.
How to patch test, step by step
- Pick a spot. The inside of your forearm works well. Make sure the skin is clean, dry, and free of cuts or irritation.
- Apply a small amount. Use a little of the product, such as a few drops of serum or a pea-sized dab of cream, on an area about the size of a coin.
- Leave it on. For leave-on products such as serums and creams, do not wash it off. For rinse-off products such as cleansers and masks, leave them on for the time in the directions, then rinse.
- Wait 24 hours. Check the spot after 24 hours, and once or twice in between.
- Decide. If the skin looks and feels normal, try the product on a small area of your face, then use it as directed. If there is any irritation, rinse the area with cool water and stop using the product.
Use products externally only, and keep them away from your eyes.
What counts as a reaction
After 24 hours, your skin should look and feel normal. Stop using the product if you notice:
- Redness that lasts or spreads
- Itching or burning
- Bumps, swelling, or a rash
- Skin that feels hot or sore
If a reaction is strong, spreading, or painful, or involves swelling of the face or lips or trouble breathing, get medical help right away. For milder reactions that do not settle, talk with a healthcare professional.
When to patch test
- Any new product, especially one with actives such as retinol, exfoliating acids, or vitamin C
- Products with fragrance, if your skin is reactive
- A new formula of a product you already use
- Several new products at once. Test each one separately.
What a patch test cannot tell you
A clear result after 24 hours is reassuring, not a guarantee. Some reactions build up with repeated use, particularly with actives, which is why it helps to start slowly. Try a new active every second or third night at first and watch how your skin responds. Forearm skin is also not identical to facial skin.
If you have reacted to an ingredient before, check the label for it. Our guide to reading an ingredient list shows how. If you are pregnant or nursing, or take medication, ask a healthcare professional about ingredients such as retinol before starting.
Where to go next
If your skin often feels reactive, our sensitive skin page and guide to fragrance-free skin care are good next stops. The retinol guide explains how to introduce that ingredient slowly. Want a routine built around your answers? Try the Find Your Routine quiz.
Frequently asked questions
Where should I patch test?
The inside of your forearm is the usual choice because the skin is easy to check and out of the way. Apply a small amount, wait 24 hours, and look for redness, itching, burning, or swelling.
Do I need to patch test every product?
It is most useful for new products, especially those with actives or fragrance, and for anyone with reactive skin. Test one product at a time so you know which one caused a reaction.
What if I get a reaction?
Rinse the area with cool water and stop using the product. If the reaction is strong, spreading, or painful, or does not settle, talk with a healthcare professional.
If my patch test is clear, can I go ahead and use the product on my face?
A clear test is a good sign, but not a guarantee. Introduce the product gradually, follow the directions, and stop if your skin becomes uncomfortable.
This content is for general cosmetic and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure, or prevent any disease or skin condition. If you have a skin condition, are pregnant or nursing, or have concerns about a product, talk with a qualified healthcare professional.
