Polysilicone-15

Polysilicone-15 is a soluble organic UV filter based on silicone that absorbs UV-B and UV-A rays. The mixture of substances absorbs UV rays in the UVB range with an absorption maximum around 312 nm.

The siloxane polymer is a colourless to light yellow liquid. The substance is used in cosmetics as sunscreen or in care products (shampoos, conditioners, hair sprays, lip balms) as UV protection.

Contact allergic reactions to the siloxane polymer have been described several times.

Parsol® SLX;

Organic light protection filters are all those UV filters whose effect is not exclusively based on the inorganic, physically active substances titanium dioxide or zinc oxide. Organic, also known as chemical UV filters, are photoactive substances that are able to absorb light quanta in a certain wavelength range (ultraviolet radiation in the range of about 280 to 400 nm = ultraviolet radiation = UVB/UVA spectrum). The absorbed UV is then released as thermal energy without penetrating the skin. In this reversible photoisomerization, the energy of the absorbed photon must correspond to the energy required to lift an electron in the molecule of the filter substance from a lower to a higher orbit. In order to protect over the entire width of the wavelengths relevant to humans from 290 to 400 nm, several chemical filters with different absorption maxima are usually combined. With a suitable combination of organic and physical filters, the content of organic filters can also be reduced with the same UV protection. This is desirable, since especially photounstable organic UV filters can cause phototoxic and photoallergic reactions depending on their concentration in the finished product.

1. Sarre ME et al (2014) Allergic contact cheilitis caused by polysilicone-15 (Parsol® SLX) in a lipcare balm. Contact dermatitis 70:119-121.