Tinosorb is a broad spectrum sunscreen (see its range in the chart above) and it is unique amongst chemical sunscreens in that it both absorbs and reflects like the inorganic filters such as zinc and titanium. But the thing that makes Tinosorb (its chemical name is bemotrizinol) stand out is that it is extremely stable, whereas many other sunscreen actives are decidely not.

In fact, there is growing concern that a lot of sunscreens don't really work. There are seven UV-A filters listed in the FDA monograph. But oxybenzone, for instance, is primarily a UV-B filter that also blocks some UV-A rays. Menthyl anthranilate is not a broad-spectrum UV-A filter. Avobenzone provides broad-spectrum UV-A blockage but quickly loses potency on the skin if not formulated properly. Sulisobenzone and dioxybenzone are difficult to dissolve and are rarely used. Two physical blockers, titanium dioxide and zinc oxide, are difficult to incorporate into formulations.

Because of these limitations, formulators often combine more than one active. This isn't always a good idea. It is well-documented that interactions between octyl methoxycinnamate (UVB absorber) and avobenzone (UVA absorber) can compromise the effectiveness of sunscreen products.

As for oxybenzone, it might be best to try to avoid it altogether. It recently underwent a review by the European Union's Scientific Committee on Consumer Products, which found insufficient data to verify the required margin of safety. The SCCP panel noted that, "In the case of Benzophenone-3 (oxybenzone), the presented publications clearly indicate that the UV-filter is a photoallergen." A 2005 study said that in combination with other chemicals it may have both human health and environmental implications. And a Swedish study concluded that it should not be used by young children.

Tinosorb, unlike other sunscreen actives, is very stable: it remains 98.4% intact. It can also partly protect other chemical sunscreens from degradation. It appears to have a good safety profile, even though current safety data are insufficient and, since tinosorb is relatively new, it is unclear whether it could produce low-level skin damage or systemic effects with long-term use. Considering that tinsorb is stable, poorly soluble and minimally absorbed by the skin, the risks appear to be low.

Tinsorb's broad range protection stands up extremely well against other high performance sunscreens, such as mexoryl in Anthelios SX, which has to be combined with two other actives in order to be full spectrum.

Frustratingly, tinosorb products are not available in the US as they are still awaiting FDA approval. You can buy it in Europe in Avene's sunscreens and in the UK in Boot's Soltan. One of the versions of tinosorb can actually be used directly on clothes and is designed to be loaded into the washing machine. So for Americans who haven't got friends making trips over from Europe, getting hold of a box of Rit Sun Guard before you hit the laudromat could be the next best thing.