How to Patch Test a New Product

Two minutes of patience prevents a week of regret. Patch testing is the cheapest step in any routine.

The method

• Apply a small amount to the inner forearm or behind the ear.
• Leave it alone for 24 to 48 hours.
• Watch for redness, itching, stinging or small bumps.
• If nothing happens, it is probably fine for wider use.

Irritation is not allergy

Irritation tends to appear quickly, on first exposure, and settles once you stop. Allergic contact dermatitis can take days to show and typically worsens with repeat use. A reaction that is severe or will not settle is a conversation for a dermatologist, who can arrange formal patch testing to identify the specific culprit.

One product at a time

The most common mistake is starting three products at once. When something goes wrong there is no way to know which one caused it. Leave about a week between introductions.