Sunscreen Formulations: A Comprehensive Review of UV Filters, Safety, and Environmental Impact

Typically, a sunscreen formulation consists of a number of UV filters, which may be either organic or inorganic. Organic UV filters are chemical compounds termed as UV-absorbers, which when applied to skin absorb the UV radiation and convert it into heat that is subsequently released by the skin to the atmosphere. Organics offer broader UV protection, a relatively large selection of UV filters is available today, and little information is available about their acute or chronic health effects on humans.  The main types of organic UV filters include benzophenones, which are used for their ability to absorb a wide range of UV radiation few are approved with regard to the concern for endocrine disruption, another type is cinnamates, which absorb UV radiation by a different mechanism and are generally considered less efficient blockers, the last type is salicylates, they provide UV absorbing ability but are not used alone as they can be irritating to skin. Inorganic UV filters have proven to have less potential for sun-induced skin damage. They differ significantly from organics as they do not absorb UV radiation, but physically scatter and reflect it. Despite the lack of relevant data, studies have proven that they possess little to no systemic absorption when applied topically and are generally recognized as safe. The inorganic filters are either zinc oxide, a white but non-staining powder that scatters UV radiation efficiently  or titanium dioxide, which is generally present in either a white or clear form depending on the degree of surface treatment that would help to inhibit scattering properties while retaining UV absorption. Concerns surrounding these inorganic filters are regarding their inhalation on spray compositions and their interaction with other active ingredients on sensitive skin.  Most compositions use a combination of organic and inorganic UV filters to eliminate the disadvantages that each pose on their own while enhancing the benefits they contribute to the sunscreen product. However, their safety profiles and potential impact on willing consumers and aquatic ecosystems is of utmost importance. As such regulatory restrictions are currently imposed on the use of organic UV filters such as oxybenzone and octinoxate. Furthermore, research Vis-a-vis potential alternative sunscreen formulations continues to be relied on to promote optimal skin protection against the hazards of UV radiation without compromising on the quality of sun protection products being offered and its effects later down the line.