two in one response! i’ve talked about mineral vs. physical sunscreen before, but i’ll restate and summarize it all here.
organic filters, aka chemical filters
these are kinda-complicated molecules that are capable of absorbing the energy of UV rays and dispersing it through heat. there’s a big array of these molecules, and new ones keep being created with better absorption profiles. USA-made sunscreen, however, does not use more modern organic/chemical filters (find out why here); for this type especially, it’s best to opt for european and asian brands.
- modern chemical filters offer better UVA protection than mineral filters. UVA radiation is the more dangerous one in the long one, being responsible for skin cancer as well as playing a role hyperpigmentation disorders and visible signs of aging (wrinkling, sagging, sun spots, etc)
- their formulation properties mean that chemical filters are more pleasant and cosmetically elegant to use, which can help you use the necessary amount to achieve the labelled spf (spoiler alert: you need a lot more than you think)
- newer chemical filters have optimized stability and so they need to be reapplied about as often as mineral sunscreens
- little to no white cast, POC-friendly!
- some people with skin sensitivities react poorly to organic filters and need to use mineral ones instead
- older chemical filters (the sort that is still used in USA-made sunscreen) were less stable and broke down after a couple hours, requiring frequent reapplication; as i’ve mentioned, this is not the case with newer filters available in other markets
these are simple mineral particles, almost always titanium dioxide and zinc oxide. these minerals reflect some of the UV light (thanks to their white cast), and absorb some of it too.
- they are better for individuals with specific sensitivities to common organic filters
- mineral filters create a strong white cast that is especially problematic for brown and black skin — novel nanoparticle versions can help improve these issues greatly, thankfully, but these are still not yet as well researched and so regulation still holds this area back somewhat
- they are generally thicker and less pleasant to apply, which leads you to applying less than you need and thus being less protected
- they are worse at protecting you from UVA rays, which as we’ve seen is something that’s rather important
- they are also not ‘set it and forget it’: both chemical and mineral sunscreens require reapplication after some hours — fewer if you’re out in the sun and actively exposed to water or sweat, more if you’re sitting still and indoors
a note on coral safety because i know this question will be asked again: according to current scientific evidence, all sunscreen is okay to wear in terms of reef ecosystems, unless you’re travelling to / swimming in areas near the reefs themselves, causing the local concentration to rise disproportionally due to currents and high rates of tourism in these areas. everywhere else, you’re fine — the effect is absolutely null at a global scale with the dilution in a planet’s worth of ocean water, and you should be more concerned with the effects of bleached industrial and agricultural substances.
and because i also know i’ll get asked again, here are my sunscreen recommendations for both categories!
lastly, a final reminder: you need to be wearing a minimum of SPF 30 broad-spectrum sunscreen every day. it’s the most basic step of skincare, and the one that’ll yield the most long-term benefits!