The Complete Beginner's Guide to Next-Gen UV Filters
Tinosorb, Uvinul, Mexoryl — decoded once and for all.
Tinosorb S and Tinosorb M have been used in Europe, Asia, and Australia for over two decades.
Next-generation filters were engineered to stay stable in sunlight rather than degrade like older ones.
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/SkincareScience: 'What's the difference between Mexoryl SX, XL, and 400?'
Sources & citations
- Mexoryl 400 randomized controlled trial, PubMed 35072138
- en.wikipedia.org ↗