Sunscreen agents can be broadly classified into two categories: organic also known as chemical and inorganic also known as physical or mineral sunscreens. These two types of sunscreens differ in their photochemical properties and their mechanisms of action in protecting the skin from ultraviolet UV radiation.Organic sunscreen agents:Organic sunscreens are composed of carbon-based molecules that absorb UV radiation. They contain chromophores, which are chemical structures that can absorb specific wavelengths of light. When organic sunscreens absorb UV radiation, their molecular structure undergoes a temporary change, which allows them to dissipate the energy as heat. This process is known as photochemical conversion. Organic sunscreens are designed to protect against both UVA 320-400 nm and UVB 280-320 nm radiation. Some common organic sunscreen agents include avobenzone, oxybenzone, octinoxate, and octisalate.Inorganic sunscreen agents:Inorganic sunscreens, also known as physical or mineral sunscreens, are composed of metal oxide particles, such as titanium dioxide TiO2 and zinc oxide ZnO . These particles act as a physical barrier on the skin, reflecting and scattering UV radiation. Inorganic sunscreens are effective against both UVA and UVB radiation. Due to their larger particle size, inorganic sunscreens tend to leave a white cast on the skin, although newer formulations with smaller particles nanoparticles have been developed to minimize this effect.Effectiveness at protecting against UV radiation:Both organic and inorganic sunscreens are effective at protecting the skin from UV radiation, but they differ in their mechanisms of action. Organic sunscreens absorb UV radiation and convert it into heat, while inorganic sunscreens reflect and scatter UV radiation. The effectiveness of a sunscreen is measured by its sun protection factor SPF , which indicates how well it protects against UVB radiation. Both types of sunscreens can achieve high SPF values, but it is important to choose a broad-spectrum sunscreen that protects against both UVA and UVB radiation.In summary, organic and inorganic sunscreens differ in their photochemical properties, with organic sunscreens absorbing UV radiation and converting it into heat, while inorganic sunscreens reflect and scatter UV radiation. Both types of sunscreens are effective at protecting against UV radiation, but their specific properties may influence an individual's choice based on factors such as skin type, cosmetic preferences, and potential sensitivities.