A practical, evidence-led guide to retinoids, vitamin C, acids and sunscreen — and how to combine them without wrecking your barrier.
Sunscreen first, always
Broad-spectrum SPF is the single most effective anti-ageing product available, and the one step that makes every other treatment worth doing. Without it, pigmentation returns and collagen-building work is undone.
Retinoids, introduced slowly
Retinoids improve texture, tone and fine lines with the strongest evidence base of any topical ingredient. They also cause the most trouble when introduced too quickly. Twice a week for a fortnight, then building up, avoids most problems.
Vitamin C and exfoliating acids
Vitamin C in the morning supports photoprotection and brightness. Acids improve texture and clarity but are easy to overuse; two or three times a week is enough for most skin.
If your skin stings, feels tight or has become reactive, the answer is almost always fewer actives rather than more products. Barrier repair comes first.