What Makes a Filter 'Broad-Spectrum'?
The label term that matters more than the SPF number.
Bemotrizinol (Parsol Shield) is approved in formulas up to 6% for adults and children 6 months and older.
Bemotrizinol retains roughly 98% of its activity after intense UV exposure, so a broad-spectrum, photostable filter keeps working through a full day in the sun.
Frequently asked questions
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.
What is bemotrizinol (Parsol Shield)?
Bemotrizinol (trade name Parsol Shield; also known as Tinosorb S) is a broad-spectrum UVA+UVB filter that is highly photostable. On June 9, 2026 the FDA approved it — the first new sunscreen active added to the US monograph since the 1990s — for adults and children 6 months and older at up to 6%.
r/AsianBeauty: 'Can someone explain what Tinosorb S and M actually do?'
Sources & citations
- Mexoryl 400 randomized controlled trial, PubMed 35072138
- fda.gov ↗