Over 80% of sunscreen performed below their labelled efficacy (2020)

Is mineral sunscreen a safer bet than regular sunscreen, since it physical blocks the sunrays?

This is pretty widely held misconception. Today's chemical and mineral sunscreens both primarily operate through UV absorption rather than reflection: https://www.bbc.com/future/article/20250718-which-kind-of-su...

No. I saw a good video on this recently. Essentially there is no fundamental difference in efficacy between different active ingredients.

No.

Maybe? But it's probably easier to wipe or sweat off. I'm also a huge fan of mechanical sun protection (hats, sun shirts, rash guards, etc etc)

no. there might be some mild advantages (less environmental damage? also protection from excessive IR+VIS?) But in the published testdata listed above there are mineral sunscreens promising 50 SPF and not getting there either. Combined with the often more difficult application you might end up with even less protection. So buyer beware (or wear hats and shirts).

It's not "safer" from the sun, but could be safer from side effects of the chemicals used in typical sunscreen.

The FDA listed 12 typical sunscreen ingredients, such as avobenzone, octinoxate, and oxybenzone, as not currently having sufficient data to be recognized as safe and effective. They're absorbed into the bloodstream and studies have found them to persist for weeks.

Based on current data, the FDA categorized only two sunscreen ingredients as safe and effective, the mineral-based ones: zinc oxide and titanium dioxide, which don't permeate the skin much.

"Although the protective action of sunscreen products takes place on the surface of the skin, there is new evidence that at least some sunscreen active ingredients are absorbed through the skin and enter the body. This makes it important for FDA to determine whether, and to what extent, exposure to certain sunscreen ingredients may be associated with any safety risks. FDA has requested data from industry to confirm the safety of sunscreen active ingredients."[0]

[0] https://www.fda.gov/drugs/understanding-over-counter-medicin...

Much worse, if for no other reason than applying it and having it leave behind a white residue on your skin makes people much less likely to reapply once it rubs off.

I always pack my own sunscreen when traveling to islands that ban normal sunscreen. I feel bad if it actually damages the reefs, but reef safe sunscreen is terrible at protecting from the sun.

That's not okay. If reef safe sunscreen isn't sufficient for what you need, then you should find a different way to protect yourself than one that damages reefs.

It’s okay. I’m not actually spending time in the ocean. More of a “sit by the pool and explore the island” kind of guy!

Reef-safe sunscreen is bullshit anyway. The marketing is well out in front of the science. There's no real evidence it's harmful to reefs and there's no real evidence (or reason to believe) the other kinds of sunscreen aren't just as harmful to reefs. It's just marketing jibber jabber.

https://www.consumerreports.org/health/sunscreens/the-truth-...

The sunscreen x reef safety research isn't very good, and the marketing is well out in front of the science on this issue.

Today's sunscreens are complex cocktails of different molecules. The most advanced and efficient ones use both, inorganic and organic, chemicals, e.g.:

  Zinc oxide – for the broadest UV-A and UV-B absorption.

  Titanium dioxide – for UV-A absorption.

  Diethylamino hydroxybenzoyl hexyl benzoate (DHHB) – for UV-A absorption.

  Octyl methoxycinnamate – for UV-B absorption.

  Octocrylene – for short-wave UV-A and UV-B absorption.

  Bemotrizinol – a broad-spectrum UV absorber, absorbing both UV-A and UV-B rays.

  Octyl triazone (ethylhexyl triazone) – for UV-B absorption.

The actual composition varies, but it is going to have a combination of multiple compounds due to them having different absorption peaks, e.g. bemotrizinol has two absorption peaks, 310 and 340 nm, and DHHB peaks out at 354 nm.. The compounds also have synergistic effects when blended with one another, so the sunscreen design is a science on its own.