Effect of daily sunscreen application on vitamin D: findings from the open-label randomized controlled Sun-D Trial.

What Was Tested

This randomized controlled trial looks at Vitamin D, K2, Magnesium and Zinc.

It is uncertain whether this translates to real-world settings.

Who Took Part

PubMed indexes the participants as teenagers, young adults, adults, middle-aged adults and older adults, both men and women.

The researchers conducted a population-based open-label randomized controlled trial in Australian participants aged 18-70 years who were not routinely using sunscreen or taking vitamin D supplements.

The researchers measured 25(OH)D concentration at baseline (winter/spring 2022) and at the end of summer and winter 2023; participants with no postbaseline concentrations (n = 11) were excluded from analyses.

How the Study Was Run

The design is described as randomized and open-label.

Because people in this Vitamin D, K2, Magnesium and Zinc study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

Being open-label, the Vitamin D, K2, Magnesium and Zinc study did not mask who received what.

The primary outcome was change in 25(OH)D concentration from baseline.

The researchers analysed data using mixed-effects models and Poisson regression.

The researchers stratified their analysis by baseline 25(OH)D concentration, residential UV radiation (UVR) zone, skin exposure (derived from time outdoors and clothing use) and personal UVR exposure (derived by combining UVR zone and skin exposure).

Sample and data analysis were performed blind to randomization group.

What Was Measured

Topics PubMed links to this paper include Sunscreening Agents, Vitamin D, Vitamin D Deficiency, Sun Protection Factor, Seasons, Australia and Sunlight.

What This Means in Plain Language

The paper is a randomized and open-label study of Vitamin D, K2, Magnesium and Zinc.

The abstract goes on to report its results in about 9 sentences; this page does not restate them, so read the paper for the findings and their limits.

The publication is from 2025 (The British journal of dermatology), a journal based in England.

More context: the Vitamin D, K2, Magnesium and Zinc compound page, all human trials.