Summer is almost upon us with its long sunny days. As humans, we require sunlight to produce Vitamin D. However, excessive sun exposure results in sunburn and may instigate skin cancer. Sunscreen allows us to enjoy those hours of sunshine without our skin feeling crispy and decreases the potential of skin cancer development. But what are these chemicals in sunscreen that reduce our skin’s exposure to sunlight? Could they have adverse effects?
Sunscreen protects against the two types of ultraviolet (UV) rays in sunlight: UVA and UVB. UVA are long wave which allows them to reach the second dermal layer of skin and cause skin aging. UVB are short wave and cause sunburn by damaging the first dermal layer of skin. Both types of rays may result in skin cancer. Sun Protection Factor (SPF) measures the ability of sunscreen to protect against UVB rays. A broad spectrum sunscreen protects against UVA and UVB rays, though the amount of protection against UVA rays cannot be determined.
A common ingredient in sunscreen is the carbon-based chemical oxybenzone, which is also referred to as benzophenone-3. Oxybenzone prevents the skin’s exposure to UVA and UVB rays by absorbing the UV rays itself. The structure of oxybenzone eventually breaks down from acquiring this excess energy, which is why it is necessary to re-apply sunscreen every few hours.
Oxybenzone is an effective sunscreen chemical but it may have long term bodily injury effects. Since oxybenzone is carbon-based, it is absorbed by the skin and may enter the blood stream. It has also been hypothesized oxybenzone alters reproductive hormone concentrations. Praedicat’s analytics on scientific literature show a general acceptance that oxybenzone to be a low reproductive risk. Oxybenzone is also a developmental risk according to our analysis. In fact, our analytics show the general acceptance of developmental risk of oxybenzone to be higher than the reproductive risk.
Zinc oxide and titanium dioxide are inorganic chemicals also found in sunscreen. These mineral oxides absorb UV rays while also simultaneously reflecting and scattering them. They also reflect and scatter visible light, which is why these mineral oxides look white on skin.
To minimize their appearance as a white paste, many sunscreen formulations use nanoparticle sizes of these mineral oxides. Nanoparticles are a known inhalation risk, so these mineral oxides are not incorporated in the increasingly popular spray-applied sunscreens. Even when used in sunscreen lotion, these mineral oxide nanoparticles may induce lung injury and lung cancer. Our analytics show the general acceptance in the scientific literature that titanium dioxide nanoparticles cause lung and nervous system injuries. Scientists also support the hypotheses zinc oxide nanoparticles may cause liver, lung, reproductive, and nervous system damage.
In addition to the chemicals absorbing UV rays in sunscreen, there are other chemicals in sunscreen that increase the risk for long term bodily injury. Two examples are dicyclohexyl phthalate and di-n-pentyl phthalate. Praedicat has determined these phthalates may be associated with developmental and reproductive risks.
Sunscreen is a great preventative measure to combat the sun’s damaging rays. We use sunscreen frequently and may even apply it multiple times a day. Sunscreen protects us from short term consequences, and may even prevent long term ones as well. However, consumers should be made aware of the potential long-term bodily injury risks from chemicals commonly found in sunscreen.