Sun protection vs sunlight exposure — what does the evidence actually say?

This is one of the more genuinely unsettled comparisons on the site, and both individual topic pages already flag real caveats. Sun protection's evidence is surprisingly inconclusive: a meta-analysis of 29 studies covering over 313,000 people found no significant association between sunscreen use and skin cancer risk overall, and noted that a positive association seen in older studies has steadily weakened since the 1980s — likely reflecting that people already at higher risk tend to use more sunscreen (confounding by indication), not that sunscreen doesn't work. Sunlight exposure's evidence runs the other direction but is just as confounded: cohorts finding lower mortality with more sun exposure can't rule out that people who avoid the sun already have worse underlying health. Neither evidence base is strong enough to overturn standard medical guidance here — the honest takeaway is that the population-level data on both sides is messier than commonly assumed, not that either practice has been disproven.