About Tinosorb M Bisoctrizole in DIY Skin Care
Tinosorb M is an innovative UV filter with a hybrid technology that combines organic filters with inorganic micro-fine pigments. It a water soluble ingredient that is added to sunscreens to provide additional UV absorption. Tinosorb M is presented as a 50% aqueous dispersion of less than 200nm micro-particles which can be easily incorporated in a sunscreen in the water phase of an emulsion. It has numerous advantages: easy to use, can be cold processed, efficient at low concentrations and contains no preservatives.
Recent research showed that a microfine organic-inorganic technology ensures enhanced SPF and UVR coverage, because the two components have a synergic effects . Tinosorb M is acts both as an organic UV filter by absorbing the UV radiation and as an inorganic filter (due to the microfine pigment particles) deflecting the ultraviolet radiation .
Figure 1 – Tinosorb M organic-inorganic features 
Tinosorb M is very stable  and highly efficient in protecting against both UVA and UVB radiation due to its triple action: UV absorption by a photostable organic molecule, light scattering and light reflection by its microfine structure. This enables Tinosorb M can absorb both UVA and UVB rays, providing a complete protection against the whole ultraviolet spectrum.
The active ingredient in Tinosorb M, Bisoctrizole is a broad-spectrum sunscreen that absorbs UVR and due to its microfine structure, with particles smaller than 200nm also reflects and scatters. Thus, Tinosorb M is able to succeed where other organic UV filters do not, especially in the UVB area. Research shows that formulations with Tinosorb M have efficiency comparable with zinc oxide (ZnO) and titanium dioxide (TiO2) .
Figure 2 – UVA and UVB absorption spectrum of Tinosorb M (2)
Studies assessing bisoctrizole’s safety showed that when formulated into a sunscreen, bisoctrizole has minimal skin penetration, which makes it completely suitable for cutaneous use . Also, unlike other chemical (organic) sunscreens, Tinosorb M is very stable when it comes to UVR photodegradation. Furthermore, bisoctrizole acts as a stabilizing agent for less stable compounds such as avobenzone . Regarding the concern that like other organic UV filters, BASF’s Tinosorb product range may disturb the estrogenic balance, by interacting with the estrogen receptors, laboratory research showed that tinosorb products are safe. No estrogenic activity was registered . Concluding, it can be said that Tinosorb is not only one of the most efficient sunscreen ingredient but also that it is very safe for use.
Note that some studies
(by the same authors) indicate that Tinosorb M, containing decyl glucoside, is a frequent cause of allergic contact dermatitis.
We suggest that you start out with using a small percentage of this UV filter, test it first on the inside of your elbow for a period of time and, if there are no problems, gradually increase the amount (up to 10%).