Yes. Daily broad-spectrum sunscreen has among the strongest peer-reviewed evidence of any anti-aging intervention, and the study establishing it is one of the more rigorous dermatology randomized trials ever conducted.
The Nambour trial. Hughes and colleagues at QIMR Berghofer Medical Research Institute randomized 903 adults in Nambour, Australia, to either daily sunscreen use or discretionary use, over 4.5 years. Hughes' 2013 Annals of Internal Medicine paper documented the outcome: the daily-sunscreen group had 24% less measurable skin aging than the discretionary group after 4.5 years. Peer-reviewed, randomized, controlled (Hughes, 2013).
That's a rare level of evidence for any skincare intervention.
Why "every day" matters even indoors or in winter:
- UVA passes through glass. Car windows, home windows. UVA is the primary driver of dermal photoaging (Krutmann, 2017).
- Cumulative dose is what damages. Small daily exposures over decades produce more photoaging than occasional intense exposures.
- Sixty percent of annual UV load happens May-September. But that leaves 40% distributed across the rest of the year that skin still needs protection from.
Practical:
- Broad-spectrum SPF 30+ every morning
- Reapply if outdoors more than 2 hours
- Include neck, chest, hands — the areas that show photoaging fastest
- Tinted mineral options if concerned about visible light (particularly relevant for melasma)