Products that need a patch test
Not every product needs one. Gentle moisturizers and cleansers can often skip it, but test these before your first full use.
- Retinoids such as retinol: stinging and flaking are common at the start.
- Exfoliating acids such as AHA and BHA: they can irritate the skin barrier.
- Heavily fragranced products: fragrance is a common cause of skincare allergies.
- New brands or strong actives: you do not yet know how your skin will react.
If your skin is sensitive or eczema-prone, test every new product.
Where to test and how to apply
Use a spot that will not get rubbed or washed off, such as the inner arm or the crook of the elbow (AAD). Behind the ear or along the inner jaw also works.
- Apply your usual amount to a coin-sized area.
- Do not wash or rub the area during the test.
- Do not layer other products there. If a reaction appears, you will not know what caused it.
If your arm is fine, try one small spot on your face (cheek or jawline) before using it all over. Facial skin is often thinner and more reactive.
Test period: 7 to 10 days
The AAD method is to apply the product to the same spot twice a day for 7 to 10 days. If there is no redness, itching or swelling, you can start using it.
It takes over a week because there are two kinds of reaction. Irritation shows up soon after you apply a product. An allergic reaction involves the immune system, so it can appear later or only after several uses. Stop after one day and you can miss it.
If a reaction appears, gently wash the area right away and do not use that product again.
How to read a reaction
- Mild redness or stinging is likely irritation. Rinse, calm the skin and pause that product.
- Itching, swelling or hives may be an allergy. Do not use that product.
- Blisters or strong swelling and pain call for a dermatologist.
- No reaction after 7 to 10 days means you can use it. One more check on a small facial spot is safer still.
Common mistakes
- Stopping after one day: allergic reactions often come late.
- Layering other products on the test spot: it muddies the result.
- Assuming your face is fine because your arm was: your face can be more reactive.
- Assuming once fine means always fine: allergies can develop with repeated use. Retest when the formula or strength changes.
Frequently asked questions
Do I need to patch test every product?
Gentle moisturizers and cleansers can often skip it. Test retinol, AHAs and BHAs, heavily fragranced products and any new active. If your skin is sensitive or eczema-prone, test every new product.
Can I wash the test spot during the test?
The product needs to stay on the skin for an accurate read. In the shower, avoid the spot or cover it with a waterproof bandage.
If nothing happens, is it completely safe on my face?
It means the product was fine on that spot for that period. Your face can be more reactive and allergies can develop over time, so it is not a guarantee. It is still far safer than skipping the test.
My sensitive skin reacts to everything. Is patch testing still worth it?
Even more so. Knowing which ingredients set you off helps you choose the next product. If reactions keep happening, choose products with less fragrance and fewer preservatives, and see a dermatologist to narrow down the cause.
Skin Warning
If redness, itching, or swelling appears during the patch test, rinse the area with cool water and apply a calming product. Stop using the product and consult a dermatologist if the reaction is severe or does not settle.
References
INGREDIENT CHECK
Curious what goes into your own products?
Type a product name and get a free ingredient analysis.
