Introducing a new active ingredient gently

One new product at a time

If you change several products at once and your skin reacts, there’s no way to know which one is responsible. Introduce just one new product at a time, and wait two to three weeks before adding another.

The patch test

Before applying a new product to your whole face:

1. Apply a small amount behind your ear or on the side of your neck, once or twice a day.
2. Watch the area for a few days.
3. If you notice redness, itching, swelling or burning, don’t use the product.

This test doesn’t guarantee perfect tolerance on your face, but it limits unpleasant surprises.

Building up strong actives

Retinoids (retinol, retinal)

• Start with a low concentration, two evenings a week.
• Increase gradually over several weeks, if your skin tolerates it.
• A pea-sized amount is enough for the whole face, avoiding the eye and lip areas.
• Slightly dry or lightly peeling skin at first is common; a moisturizer helps.
• In the evening only, with sunscreen every morning.

Exfoliating acids (AHA, BHA, PHA)

• Once or twice a week at first, then two to three times.
• Never on the same evening as a retinoid.
• Avoid irritated areas and the eye area.

Vitamin C

• In the morning, under your sunscreen.
• If it stings, choose a lower concentration or a gentler derivative.
• Replace it if it turns brown: that’s a sign it has oxidized.

Special cases

• Pregnancy and breastfeeding: retinoids are not recommended. Ask a healthcare professional for advice before any new active.
• Ongoing dermatological treatment: follow your dermatologist’s instructions before adding anything.
• Very reactive skin or skin prone to redness: favor the simplest formulas and talk to a dermatologist about it.