Most of the early fine lines, rough texture and uneven tone people notice in their 20s and 30s are driven by UV, which is why daily sunscreen is the best-proven way to keep skin looking younger for longer. Add retinol at night, slowly, for smoother-looking skin over about 3 to 6 months, and treat everything else as a supporting step.
Skin ages in two ways at once: natural ageing, and the extra ageing from outside, mostly UV, plus smoking and pollution. The outside kind shows as roughness, sallowness, fine lines around the eyes and forehead, uneven pigment and visible vessels [3].
UVA is the main driver. Its longer wavelength reaches deeper into skin, where it increases enzymes that break down collagen; visible light adds to pigment changes [2].
The best evidence that sunscreen slows this comes from Queensland. In the Nambour trial, 903 adults under 55 were randomised to daily sunscreen or using it when they chose; over four and a half years, the daily group showed no detectable increase in skin ageing and 24% less ageing than the comparison group [1].
Dehydration makes lines look deeper than they are, which is why hydrating products can soften their look the same day, while real change from retinoids takes months [6][9].
When to see a doctor
You want stronger, prescription-strength retinoid treatment: a GP or dermatologist can discuss options such as tretinoin [4].Retinol causes swelling, blistering or a rash that spreads; stop and see your GP. Some dryness, redness and peeling in the first weeks is common [4].A spot, freckle or mole is new, changing in size, shape or colour, itchy, bleeding or not healing, or a new mole appears after 25: that needs a skin check, not skincare [12].
There's no set age. Many people start in their mid to late 20s once daily sunscreen is a habit; the trials were in adults, and most were older than 30 [4][5].
General information only, not medical advice.