A recent study published in the British Journal of Dermatology investigated how daily use of SPF50+ sunscreen affects vitamin D levels. Researchers from Australia's Sun-D Trial followed 639 adults over one year, comparing those who applied high SPF sunscreen daily with a control group using regular sun protection. Results showed that while both groups saw vitamin D increases from winter to summer, the sunscreen group had significantly smaller gains. By study end, 46 per cent of daily sunscreen users were vitamin D deficient compared to 37 per cent in the control group. However, experts emphasise that sunscreen remains crucial for preventing skin cancer and sun damage. The findings suggest that people who apply SPF50+ sunscreen every day when the UV index reaches three or more should consider taking vitamin D supplements, especially during winter months. This was the first global study examining real-world effects of daily high SPF sunscreen use on vitamin D status.
Understanding the Study Design and Key Findings
The Sun-D Trial recruited adults from four eastern Australian states who were not regular sunscreen users. Participants were divided randomly into two groups. The sunscreen group received SPF50+ sunscreen and instructions to apply it daily on exposed skin when the UV index forecast reached three or more. The control group continued their normal sun protection habits. Vitamin D measurements were taken at three points: late winter/early spring at start, late summer midway, and late winter at conclusion. While average vitamin D levels rose in both groups during summer months, the increase was markedly lower among daily sunscreen users. The difference in deficiency rates between groups confirms that high SPF sunscreen does reduce vitamin D production in everyday conditions.
Practical Recommendations for Sun Protection and Health
Despite the findings, health experts stress that Australians must continue using sunscreen daily when UV levels are high, as it significantly reduces skin cancer and sunspot risks. However, daily sunscreen users should consider taking affordable vitamin D supplements, costing as little as 5 cents per day. Supplements are especially important during winter when deficiency becomes more common, particularly in southern states like Tasmania where 46 per cent of people are deficient in winter versus 16 per cent in Queensland. People who spend extended time outdoors should combine sunscreen with protective clothing, hats, sunglasses, and shade. Those covering skin extensively or rarely going outdoors between 8am and 4pm face higher deficiency risk and may start supplements without prior testing.
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