Differin brought genuine dermatology grade acne treatment within easy reach. Its active ingredient, adapalene, is a retinoid, and retinoids work where acne actually starts, inside the pore. By keeping skin cells from clumping together and clogging the follicle, it both clears existing spots and heads off the next crop before they form.

That preventive action is what separates a retinoid from a simple spot treatment. The trade off is patience: skin sometimes looks a little worse before it turns the corner, and the real reward arrives after a couple of months of steady nightly use. Stick with it, and the change can be considerable.

• A retinoid that treats and prevents in one step
• Works deep in the pore where acne begins
• Applied once nightly, with results building over weeks

For external use only. Retinoids make skin more sensitive to sun, so daily sunscreen is essential. Keep it away from the eyes and lips.

Apply a thin layer to clean, dry skin once a day in the evening, across the whole affected area rather than only on spots. Start every other night if your skin is sensitive. Always follow with sunscreen the next morning.

Adapalene 0.1 percent, a topical retinoid.

Dryness, redness, flaking and a little stinging are common in the first weeks as skin adapts, then ease. Sun sensitivity is increased throughout treatment.

For external use only. It increases sun sensitivity, so daily sunscreen is essential. Keep away from the eyes, lips and broken skin. Expect a short adjustment period before skin improves.