How to Do a Patch test

If you’re trying henna or jagua for the first time, we recommend doing a patch test first. Even if you aren’t allergic to henna or jagua, you might be sensitive or allergic to one of the other ingredients - such as essential oils.

For a proper patch test, we recommend the testing process from the American Academy of Dermatology. You can also view it directly on their website here.

To test a skin care product, dermatologists recommend the following tips:

• Apply the product to a test spot twice daily for seven to 10 days. Choose a quarter-sized spot on your skin where the product won’t be rubbed or washed away, such as the underside of your arm or the bend of your elbow. Use the normal amount and thickness you would use as if you were applying the product regularly.

• Leave the product on your skin for as long as you would normally. If you’re testing something that you would usually wash off, like a cleanser, keep it on your skin for five minutes or as long as the instructions say.

• If after seven to 10 days you don’t have a skin reaction, such as red, itchy, or swollen skin, go ahead and use the product.

• Keep in mind that some ingredients, such as retinol and glycolic acid, can irritate your skin, particularly if your skin is sensitive. This is normal and temporary.

• If you develop a skin reaction, gently wash the product off as soon as possible, and don’t use it again. Apply a cool compress or petroleum jelly to relieve your skin, if needed. If your reaction to a product is severe and not relieved with cool compresses or petroleum jelly, you may need to see a dermatologist to help manage your symptoms.

Source: https://www.aad.org/public/everyday-care/skin-care-secrets/prevent-skin-problems/test-skin-care-products