What are the active sunscreen ingredients that will provide photo protection?
Encouraging photoprotection is the leading preventative health strategy employed by physicians involved in skin care. Although sun avoidance is most desirable, outdoor occupations and lifestyles make total avoidance impossible for many individuals. The regular use of sunscreens represents a practical compromise in this regard. Sunscreens prevent the formation of squamous cell carcinomas in animals. In humans, the regular use of sunscreens has been shown to reduce actinic keratoses, solar elastosis, and squamous cell carcinoma.
@srabanti Sunscreens have traditionally been divided into chemical absorbers and physical blockers on the basis of their mechanism of action. Chemical sunscreens are generally aromatic compounds conjugated with a carbonyl group. These chemicals absorb high-intensity UV rays with excitation to a higher energy state. The energy lost results in conversion of the remaining energy into longer lower energy wavelengths with return to ground state. Inorganic particulate sunscreens, zinc oxide, and titanium dioxide, can reflect or scatter UVR. Micronized forms of physical blockers may also function by absorption. Allowable ingredients and maximum allowable concentrations, as listed in the FDA monograph, are shown in the Table below. Europe, Australia and Japan allow additional active ingredients. In 2014, the US Congress passed the Sunscreen Innovation Act to establish an expedited review process to allow approval of additional sunscreen ingredients. To date, no new ingredients have been approved, several of which have been used in Europe for over a decade.