Light stabilizer

Ingredients with the function of a light stabilizer help the formula to break down less under the influence of light, primarily ultraviolet. This is important not so much for direct skin or hair care as for preserving the properties of the product itself: such substances reduce fading, yellowing, odor changes and unwanted viscosity shifts, especially in transparent or translucent packaging. According to BASF, photosensitive systems can lose color, stability and uniformity under the influence of radiation, and special UV absorbers and other light-stabilizing components help slow down these processes. (care360.basf.com)

In sunscreens, this feature is especially valuable because some UV filters can gradually disintegrate in the light and work worse. In this case, the light-stabilizing components maintain the photostability of the formula and help maintain the claimed protection for longer. For example, BASF industry materials note that Octocrylene or BEMT stabilization is often used for filters that are not resistant to light, such as avobenzone. The European scientific materials of SCCS also mention that some cosmetic ingredients, for example Benzophenone-1, are used as a light stabilizer and UV absorber. (personal-care.basf.com)

For the consumer, this means a more predictable quality of the product during its shelf life: texture, shade, aroma and effectiveness change less when stored in the light. In formulas for hair and skin, such components indirectly increase the comfort of use, because the product remains longer as intended by the manufacturer. Typical examples of ingredients associated with this function are Benzophenone—1 and Octocrylene in formulations where it additionally helps to enhance the light stability of some UV filters. (health.ec.europa.eu)