DIY Sunscreen Is Dangerous — Here's the Chemistry Why

The evidence is mixed but reassuring: most studies find that sunscreen, as people actually use it, does not cause vitamin D deficiency — partly because no one blocks 100% of UV. If you're concerned, dietary sources and supplements are a safer route than deliberate unprotected sun exposure.

For the vast majority of people, no — major dermatology bodies consider sunscreen safe and effective, and the proven risks of unprotected UV (skin cancer, premature aging) are far greater. The FDA is studying how some chemical filters are absorbed, but absorption alone does not mean harm.

No credible evidence shows sunscreen causes cancer; the established science is that UV exposure causes skin cancer and sunscreen helps prevent it. The myth usually stems from misread filter-absorption studies or one-off benzene contamination findings (benzene is a manufacturing impurity, not a sunscreen ingredient).