Retinol

What it does

The most-proven active in skincare. Retinol speeds cell turnover to clear acne, smooth texture, fade post-acne marks and soften fine lines. Start low (around 0.3-0.5%) and slow - two or three nights a week - and expect some dryness while your skin adjusts.

How to use it

Night only. Cleanse, dry, pea-size amount, then moisturizer. Buffer with moisturizer first if you're sensitive. SPF every morning - retinoids make skin more sun-sensitive.

What not to mix it with

• benzoyl peroxide - see Retinoid + benzoyl peroxide
• AHAs - see Retinoid + AHA
• BHAs - see Retinoid + BHA
• vitamin C (same session) - see Retinoid + vitamin C
• sulfur - see Sulfur + retinoid
• PHAs (if you're reactive) - see PHA + retinoid

What it gets along with

Fine with niacinamide (it calms retinoid irritation) and ceramide moisturizers (they cushion without cancelling). Adapalene is the one retinoid that tolerates benzoyl peroxide.

Not recommended during pregnancy or nursing - confirm anything in this family with your doctor.