Ultraviolet exposure, especially UVA, may lower blood pressure (Vitamin D, Magnesium better than UVA) - review
Effects of ultraviolet light exposure on blood pressure: a systematic review
Photochemical & Photobiological Sciences, July 2026, https://doi.org/10.1007/s43630-026-00970-5
Pirus Ghadjar et al.
Summary by GPT-5.6 Luna - August, 2026
This systematic review of 14 human studies suggests that ultraviolet (UV) exposure—particularly UVA—can lower blood pressure, potentially through a mechanism that is independent of vitamin D. The authors searched PubMed/MEDLINE, Embase, and Web of Science through March 22, 2026, and included randomized trials, clinical studies, and observational studies.
The strongest evidence concerns UVA. In one randomized trial of 24 people with mild hypertension, 5 J/cm² of full-body UVA daily for 14 days produced reductions in both clinic and 24-hour systolic and diastolic blood pressure. Other experimental studies found acute reductions after whole-body UVA exposure. A study of 79 nursing-home residents found that UV exposure twice weekly for six months reduced blood pressure, whereas oral vitamin D supplementation did not fully reproduce the effect.
The proposed mechanism is particularly interesting for VitaminDWiki: UVA can release nitric oxide (NO) and related compounds stored in the skin, producing vasodilation and lowering systemic vascular resistance. The review emphasizes that this mechanism appears to operate independently of vitamin D synthesis.
The evidence is not uniformly positive. One randomized trial found no significant effect on blood pressure or cardiovascular risk factors. The studies were highly heterogeneous in wavelength, dose, duration, exposed body area, and population, and many were small and short-term. The review therefore concludes that UV exposure cannot currently be recommended as a treatment for hypertension.
What this does not show / limitations: This review does not demonstrate that vitamin D supplementation lowers blood pressure, nor does it establish that deliberately increasing UV exposure improves cardiovascular health or reduces mortality. It also cannot establish an optimal safe UV dose. Long-term UV risks, including skin cancer and photoaging, were inadequately assessed in the included studies.
Related in VitaminDWiki
Vitamin D
- Hypertension is half as likely in those with good vitamin D and physical activity
- Less sun (less vitamin D), 1.4 X higher risk of hypertension
- Hypertension, Vitamin D, and Vitamin D Receptor
- Hypertension not reduced much if use less than 5,000 IU of Vitamin D – meta-analysis
- Hypertension risk decreased 10X by increasing vitamin D levels to more than 40 ng
- What Do We Know and Do Not Know About Vitamin D and hypertension
Magnesium
- Magnesium raised Vitamin D, lowered blood pressure and Ca to Mg ratio – RCT
- Magnesium reduces hypertension - FDA allows claim
- Hypertension treatment needs at least 600 mg of Magnesium (49 trials)
- MAGNESIUM IN MAN - IMPLICATIONS FOR HEALTH AND DISEASE – review 2015
- Magnesium reduces inflammation (CRP) and increases nitric oxide – meta-analysis
Nitric Oxide ( from UVA, etc)