Sunscreen, retinoids and vitamin C: what really helps ageing skin?

What happened

Anti-ageing shelves are crowded with serums promising firmer, brighter, younger-looking skin. Three ingredients appear again and again: sunscreen, retinoids and vitamin C.

Rather than rank brands we haven't independently compared, it is more useful to ask what the ingredient is supposed to do, what was tested in people, and whether the findings apply to the product on the shelf.

Sunscreen: preventing damage rather than turning back time

A community-based Australian randomised trial followed adults assigned to regular daily broad-spectrum sunscreen or discretionary use. Over roughly four and a half years, researchers found less measured skin ageing in the daily-use groups. The trial included 903 adults under 55, though not everyone had complete measurements.

This is meaningful because it followed people over years instead of relying on short-term photographs or a laboratory test. It does not mean any sunscreen reverses existing wrinkles or prevents every visible change.

The American Academy of Dermatology advises broad-spectrum sunscreen of SPF 30 or higher for outdoor protection, alongside protective clothing and shade. A product also needs to feel comfortable enough that you will actually use it.

Retinoids: more evidence, more need for caution

Retinoids are relatives of vitamin A. Some are prescribed; others, such as retinol, are found in over-the-counter products.

A two-year placebo-controlled trial in people with photodamaged facial skin found improvements with topical tretinoin compared with the comparison cream. Reviews of multiple trials also find evidence for improved signs of photoageing, but the size of improvement and how people tolerate treatment differ.

The American Academy of Dermatology warns that these products can irritate or dry skin. It advises that retinoids should not be used during pregnancy; people with sensitive or inflamed skin need extra care and professional advice.

A trial of prescription tretinoin does not prove that every shop-bought 'retinol' product has the same effect.

Vitamin C: interesting, but not a universal fix

Vitamin C is an antioxidant often sold in serums. A 2023 systematic literature review narrowed more than 5,000 search records to just seven eligible studies. Every included study used vitamin C alongside other ingredients or treatments. That makes it difficult to isolate what vitamin C itself contributed to changes in wrinkles. Different formulations, study durations and outcome measures also make direct comparisons difficult.

Vitamin C may have a place in skincare, but the review called for more high-quality comparative research. Consumers should be sceptical of a brand that treats an ingredient study as proof that its exact serum reduces wrinkles. We have not independently compared individual products here.

Why it matters

The first useful decision may not be 'Which is the most expensive product?' but 'Am I trying to prevent sun damage, improve existing fine lines, or address a specific skin condition?'

Different goals require different evidence. Using several strong active products together can also make skin feel worse by causing irritation.

What we still do not know

Results from a controlled study are not a promise for every age, skin tone or skin condition. Product formulations matter. Neither a high price nor popularity online establishes effectiveness. We have not evaluated current retail prices, comparative customer reviews or specific brands, so this article does not rank the 'best' products.

Sources and conflicts

The sunscreen and tretinoin studies are published human research. Dermatology guidance comes from a professional association. The vitamin C review included seven studies, all using vitamin C with other ingredients or treatments, so it cannot establish the isolated effect of a particular vitamin C serum. We have not inspected the full funding disclosures or verified whether the vitamin C review's conclusions apply to particular brands. Product-specific claims and prices require a separate review.