Cosmetic active ingredients: a must for the cosmetic benefit

Active ingredients are what make a cosmetic product work. Everything else in the formula exists to get them stable, delivered and tolerable. Here is what that means in practice.

• Many cosmetic actives have solid evidence behind them: retinoids, hydroxy acids, vitamin C, niacinamide and the UV filters are all supported by published clinical work. One boundary is worth stating precisely, though, because it is where cosmetics legally end: a cosmetic acts on the surface and the outermost layers of skin. Some actives do reach the viable epidermis, but a product intended to act on living tissue to treat a condition is a drug, and is regulated as one. Cosmetics improve appearance; they do not cure.

• Not every active suits every user. Response varies with skin type, barrier condition, climate and what else is in the routine, and some people react to actives that most tolerate well. This is why patch testing and introducing one new product at a time are worth the patience.

• Treat manufacturer claims as a starting point. Clinical studies report averages across a panel, often under controlled use; this is a genuine result, but not a promise to any individual. Look for what was measured, on how many subjects, over what period.

• Cosmetics are regulated, but on a different basis from medicines, and the difference is worth understanding rather than dismissing. Under EU Regulation (EC) No 1223/2009, every product requires a safety assessment by a qualified assessor, a Product Information File and a named Responsible Person before it goes on sale. What is not required is pre-market proof of efficacy. So the safety framework is substantial; it is the performance claims that warrant the scepticism.

• Match the active to the concern, because none of them is general-purpose. Acne responds to salicylic acid, benzoyl peroxide and retinoids, each addressing a different driver. Dryness needs the three-part approach: humectants such as sodium hyaluronate to bind water, emollients to smooth, occlusives to slow its loss. (Vitamin E is an antioxidant that happens to be emollient; it is not primarily a hydrating active.) Pigmentation needs tyrosinase inhibitors plus, without exception, daily sun protection.

• The same active often appears in both prescription and over-the-counter products, separated by concentration and vehicle. Tretinoin is prescription-only and retinol is not; both are retinoids acting on the same receptors, with potency, evidence and irritation all scaling together. Stronger is not automatically better if it cannot be tolerated consistently.

• For anything persistent or distressing (cystic acne, melasma, rosacea, eczema), see a dermatologist. Self-diagnosis wastes months on the wrong active, and several of these conditions have effective prescription treatments that no cosmetic can match.

• Finally, the ingredients that are not actives. Calling them inactive is a legal convention rather than a description: excipients determine whether an active stays stable in the jar, whether it penetrates, whether pH sits where the active works, and whether the product is microbiologically safe at all. A vitamin C serum at the wrong pH, or a peptide in a formula that degrades it, delivers nothing. See an inactive ingredient is not a passive ingredient.

Actives decide what a product can do. The formulation decides whether it does it.