Its INCI name is a bit of a mouthful, but it's worth recognizing it as it is one of the best sunscreen agents known today. Unfortunately, it's not FDA-approved so you will not find it in sunscreens coming from the US (not because it's not good, but because US regulations make it impossible for newer sunscreen agents to get approved), but it is widely available in other parts of the world like Europe, Australia or Asia.
It's broad-spectrum (covers the whole UVB and UVA range, 280-400 nm) with peak protections at about 310 and 345 nm and unlike older sunscreen agents, it's very photostable. It hardly deteriorates in the presence of UV light and it's also useful in stabilizing other less stable sunscreen agents, like the famous UVA protector, avobenzone.
It's a new generation sunscreen agent that was specifically designed for high SPF and good UVA protection and based on a 2007 study that compared 18 sunscreen agents available in the EU it really had the best SPF protection (they used the highest concentration allowed by EU regulations from each 18 sunscreens and Trinosorb S gave an SPF 20).
It is an oil-soluble, slightly yellowish powder that is not absorbed into the skin too much, and it has a great safety profile. Unlike a couple of other chemical sunscreens, Trinosorb S (and M) does not show estrogenic activity.
Overall, we think Trinosorb S is one of the best sunscreen options available today.
Show me some proof
- Pharmazie 62: 449–452 (2007), Study of the efficacy of 18 sun filters authorized in European Union tested in vitro
- Regulatory Toxicology and Pharmacology 34, 287–291 (2001), Lack of Binding to Isolated Estrogen or Androgen Receptors, and Inactivity in the Immature Rat Uterotrophic Assay, of the Ultraviolet Sunscreen Filters Tinosorb M-Active and Tinosorb S