I know LW is US/ California heavy, but just as a counter to all the sunscreen advocates here, daily sunscreen use is probably unnecessary, and possibly actively harmful, in winter and/or at northern latitudes.
There doesn’t seem to be much data on using sunscreen when there’s no real risk to skin, but you can find a modelling study here:
”There is little biological justification in terms of skin health for applying sunscreen over the 4–6 winter months at latitudes of 45° N and higher (most of Europe, Canada, Hokkaido, Inner Mongolia etc.) whereas year-round sunscreen is advised at latitudes of 30° N (e.g. Southern U.S., Shanghai, North Africa) and lower … Using products containing UV filters over the winter months at more northerly latitudes could lead to a higher number of people with vitamin D deficiency.”
The question of what kind of sun exposure leads to visible skin aging is an empiric one. Saying “We err on the cautious side and assume that an arbitrary value of 0.5 SED could be regarded as an acceptable daily erythemal exposure” does not imply that there’s no visible skin aging under that arbitrary value.
Of course, but there reaches a level of sun exposure at which the marginal increased harm becomes negligible compared to other things that damage your skin (see this meta-analysis—photo-aging is just one component among many), and below that level you’re probably actually getting suboptimal levels of UV exposure for skin health (see this article for benefits of UV—from Norway, aptly).
I’d love to see someone try to measure and compare the specific trade-offs, but I strongly suspect that people at northern latitudes should just trust common sense—only wear sunscreen in summer months, and when you’re actually exposed to the sun for extended periods.
I know LW is US/ California heavy, but just as a counter to all the sunscreen advocates here, daily sunscreen use is probably unnecessary, and possibly actively harmful, in winter and/or at northern latitudes.
There doesn’t seem to be much data on using sunscreen when there’s no real risk to skin, but you can find a modelling study here:
”There is little biological justification in terms of skin health for applying sunscreen over the 4–6 winter months at latitudes of 45° N and higher (most of Europe, Canada, Hokkaido, Inner Mongolia etc.) whereas year-round sunscreen is advised at latitudes of 30° N (e.g. Southern U.S., Shanghai, North Africa) and lower … Using products containing UV filters over the winter months at more northerly latitudes could lead to a higher number of people with vitamin D deficiency.”
Although most approved sunscreens are generally seen as safe, there are potential systemic health risks from a few products, some proven environmental harms, a potentially increased risk of vit-D deficiency, and some time/financial costs.
The question of what kind of sun exposure leads to visible skin aging is an empiric one. Saying “We err on the cautious side and assume that an arbitrary value of 0.5 SED could be regarded as an acceptable daily erythemal exposure” does not imply that there’s no visible skin aging under that arbitrary value.
Of course, but there reaches a level of sun exposure at which the marginal increased harm becomes negligible compared to other things that damage your skin (see this meta-analysis—photo-aging is just one component among many), and below that level you’re probably actually getting suboptimal levels of UV exposure for skin health (see this article for benefits of UV—from Norway, aptly).
I’d love to see someone try to measure and compare the specific trade-offs, but I strongly suspect that people at northern latitudes should just trust common sense—only wear sunscreen in summer months, and when you’re actually exposed to the sun for extended periods.