Researchers warn daily high‑SPF sunscreen use may raise risk of vitamin D deficiency
A year‑long Australian study found higher rates of vitamin D deficiency among daily SPF50+ users but researchers say sunscreen should not be abandoned and recommend supplementation where appropriate
Leading Australian medical researchers have cautioned that diligent daily use of high‑factor sunscreen can increase the risk of vitamin D deficiency, but they stopped short of advising people to stop sun protection.
A landmark year‑long trial by the QIMR Berghofer Medical Research Institute in Brisbane, published in the British Journal of Dermatology, followed 639 adults who were not regular sunscreen users at baseline. Half of participants were instructed to apply SPF50+ sunscreen daily (with an exemption in winter months for participants in southern regions), while the other half continued their usual sun habits. After 12 months, 46% of the daily sunscreen users were found to be vitamin D deficient compared with 37% of non‑users.
Professor Rachel Neale, lead investigator and senior group leader at QIMR Berghofer, said the results do not negate the established role of sunscreen in preventing skin cancer. "Sunscreen remains a cornerstone of skin cancer prevention, backed by decades of robust evidence," she said. "Our findings simply suggest that people who are diligent about daily sunscreen use may want to consider vitamin D supplementation as a safe, effective and cheap way to maintain healthy vitamin D levels."
Vitamin D is produced in the skin in response to ultraviolet B radiation from sunlight and is also available from certain foods and supplements. It is important for bone health, immune function and general disease prevention. The institute recommended continued use of SPF50+ sunscreen when the UV index is forecast to reach at least 3 and advised that individuals who use sunscreen daily consider routine vitamin D supplementation.
The trial recruited participants from Tasmania, Queensland, New South Wales, the Australian Capital Territory and Victoria. The design excluded winter months for those in southern states to reflect seasonal variation in ultraviolet exposure. Researchers measured serum levels of 25‑hydroxyvitamin D to assess deficiency and reported the relative difference between the study arms after one year.
In an accompanying statement, QIMR Berghofer stressed that "there's no evidence that sun exposure is more effective than supplementation for maintaining vitamin D," and cautioned that sun exposure carries other risks, including increased melanoma risk in Australia, which has one of the world's highest rates of skin cancer.
The new findings arrive amid renewed public scrutiny of sunscreen efficacy in Australia. Earlier this year the consumer advocacy group CHOICE reported that 16 of 20 tested sunscreen products failed to meet their advertised sun protection factor claims. CHOICE said its testing followed the Australian/New Zealand Sunscreen Standard and urged a regulatory review. Ashley de Silva, CHOICE's CEO, said the discrepancy "warrants further investigation by the Therapeutic Goods Administration."
The CHOICE report prompted a probe by the Therapeutic Goods Administration and led to several products being removed from store shelves while authorities and manufacturers reassess labeling and testing practices. Regulators and public health experts say consistent sun protection is critical, particularly in high‑UV settings, and indicate that supplementation provides a controllable alternative for maintaining vitamin D status without additional sun exposure.
Public health practitioners noted the study's implications for clinical guidance. Health services may increasingly advise routine vitamin D testing or supplementation for patients who report daily, consistent use of high‑SPF sunscreen, particularly those with additional risk factors for deficiency such as limited outdoor activity, darker skin pigmentation, advanced age or dietary insufficiency.
The authors called for further research to refine recommendations on supplementation dosages and to evaluate whether the effects differ across demographic groups and geographic regions. Meanwhile, health authorities continue to recommend balanced approaches that protect against skin cancer while ensuring adequate vitamin D, using supplements where appropriate rather than encouraging increased sun exposure.