Vitamin D supplements vs sunlight exposure — which is better?

These are mechanistically linked — sunlight triggers your skin to produce vitamin D — but the evidence quality is not equal. Vitamin D supplementation has real trial-based support: meta-analyses show a modest all-cause mortality reduction (though inconsistent across trial populations) and a clearer, more consistent benefit for bone health and fracture risk, especially in older or deficient people. Sunlight exposure's evidence is genuinely weaker and more contested: some observational cohorts (a Swedish study, a UK Biobank analysis) found more sun exposure linked to lower mortality, but these are provocative associations that can't rule out reverse causation — people who avoid the sun may already be sicker or less active. If the actual goal is adequate vitamin D status, a supplement gives you a controlled, trial-tested dose; sun exposure carries real skin-cancer trade-offs without offering better-quality evidence in return.