Tin Oxide is a water-insoluble, inorganic metal compound that is used in cosmetic products primarily as an opacifier, viscosity regulator, and filler. Due to its opacifying properties, it gives formulations a more opaque appearance. It is used in low concentrations in both wash-off and leave-on products.(1-2)

Titanium dioxide is a white micropigment used as an opacifier, powder base, UV filter in sunscreens, and colorant (C.I. 77891).(1)

Tocopherol (vitamin E) is a powerful antioxidant that reduces oxidative stress caused by UV radiation and other environmental factors. In the skin, it protects cellular structures such as lipids, proteins, and DNA from free radicals, thereby helping to prevent light-induced skin aging (photoaging).(1-3)

Tocopheryl acetate is a derivative of vitamin E (α-tocopherol) and is one of the most commonly used antioxidants in cosmetic products. It helps protect the skin from free radicals. Compared to free tocopherol, tocopheryl acetate is significantly more stable when exposed to oxygen, light, and heat, making it particularly suitable for light-sensitive formulations such as sunscreens. Studies show that, in appropriate formulations, tocopheryl acetate can alleviate UV-induced skin reactions such as redness and swelling. Due to its good stability, it is used in many skincare products to support the skin barrier and protect against light-induced skin aging.(1-3)

Tremella fuciformis sporocarp extract, or silver ear, better known as snow mushroom (Tremella fuciformis), is a species of fungus belonging to the Tremelaceae family. It contains polysaccharides composed of mannose, xylose, and glucuronic acid.(1) These polysaccharides form a film on the skin’s surface that increases its water-binding capacity and maintains the skin’s moisture content.1 In addition, Tremella fuciformis sporocarp extract has strong antioxidant properties and thus protects against free radicals.(2-3)

Tribehenin has a wax-like consistency, which allows it to give cosmetic products a creamy to waxy texture. It is considered suitable for use in cosmetic products and has been classified as safe as part of a safety assessment of cosmetic ingredients.(1)

Triethyl citrate, also known as citric acid ester, is a solvent and diluent and is not considered to be a skin sensitizer. It is even approved for use in food products.(1)

A study also investigated the efficacy of a formulation containing triethyl citrate and ethyl linoleate on acne vulgaris. Triethyl citrate is hydrolyzed by C. acnes (which triggers acne under certain circumstances) into the diethyl ester and monoethyl ester of citric acid, as well as citric acid itself. As a result, the microenvironment of the pores becomes acidic, leading to reduced growth of C. acnes, inhibition of bacterial lipases, and modulation of the keratolytic effect.(2)

Trihydroxystearin is the triester of glycerin and hydroxystearic acid. It is used as a skin conditioner, solvent, and viscosity regulator in cosmetic formulations at concentrations of up to 5%. (1-2)