Disodium Phenyl Dibenzimidazole Tetrasulfonate

Disodium phenyl dibenzimidazole tetrasulfonate (often abbreviated as PDT) is a synthetic organic UV filter belonging to the benzimidazole class of sunscreen actives. It is designed to absorb ultraviolet radiation and convert it into heat, thereby protecting skin from sun damage.This ingredient is water-soluble, which makes it particularly suited to spray and lightweight sunscreen formulations. It works across the UVA and UVB spectrum, contributing to broad-spectrum sun protection when combined with other filters in a sunscreen product.

When UV light reaches the skin, disodium phenyl dibenzimidazole tetrasulfonate molecules absorb this energy. The ingredient then undergoes a chemical process called radiative relaxation, releasing the absorbed energy as heat rather than allowing it to damage skin cells. This heat dissipation is the mechanism by which chemical UV filters protect against photoaging and skin cancer risk.Because this ingredient fluoresces when it absorbs UV light, commercial sunscreen formulations containing it typically include fluorescence quenchers (such as troxerutin) to minimise the release of high-energy …

Apply sunscreen containing this ingredient generously to all exposed skin at least 15 minutes before sun exposure, and reapply every two hours or after swimming or sweating. As with all sunscreens, it should be part of a broader sun protection strategy that includes seeking shade and wearing protective clothing when possible.

Disodium phenyl dibenzimidazole tetrasulfonate is generally considered well-tolerated in topical sunscreen products. As with any UV filter, patch testing is advisable for those with known sensitivities to sunscreen ingredients.