Before you use anything new
Patch test
A small test before a new cream, dye or makeup. It takes four days and lowers the risk of a reaction on your face or scalp.
- Apply a small amount to the inner forearm or behind the ear.
- Leave it for 48 hours (don't wash it off early unless it stings).
- Check at 48 h and again at 96 h for redness, itching, swelling or bumps.
- Any reaction: wash off, don't use the product, and note the ingredients.
- Hair dye: patch-test EVERY time, 48 h before dyeing. Never use black henna tattoos (high PPD).
- Severe swelling, blistering or trouble breathing: seek urgent care.