Why Broad-Spectrum Beats High SPF for Cancer Prevention
UVA coverage is the part the SPF number ignores.
Bemotrizinol (Parsol Shield) is approved in formulas up to 6% for adults and children 6 months and older.
Bemotrizinol is broad-spectrum and so photostable it retains roughly 98% of activity after intense UV exposure.
Questions we get a lot
What does broad-spectrum protection actually mean?
'Broad-spectrum' means a sunscreen protects against both UVA and UVB. In the US a product must pass an FDA critical-wavelength test to make the claim. Because SPF only measures UVB protection, broad-spectrum labeling is how you know you're also covered against deeper, aging UVA rays.
Why are some UV filters more photostable?
A photostable filter keeps absorbing UV without breaking down in sunlight. Older filters like avobenzone can lose protection within an hour unless paired with stabilizers such as octocrylene. Next-generation filters are engineered to stay chemically stable, so protection lasts longer — though reapplication is still advised.
What is the difference between Mexoryl SX, XL and 400?
All three are L'Oréal/BASF UVA filters. Mexoryl SX (ecamsule) covers shorter UVA; Mexoryl XL (drometrizole trisiloxane) is broad-spectrum and oil-soluble; and Mexoryl 400 (MCE) targets ultra-long UVA1, peaking around 385 nm — the deep wavelengths most older filters miss.
r/AsianBeauty: 'Can someone explain what Tinosorb S and M actually do?'
