Does sunscreen block infrared light? No, and you don't need it to. Learn why UVA/UVB protection with broad-spectrum sunscreen is key.
The quick answer is no: sunscreen does not block infrared light, and you do not need to block it.
The wavelengths of UV coming from the sun are classified as UV-A (320–400 nm), UV-B (290–320 nm), and UV-C (100–290 nm). UV-C has the highest energy, making it the most dangerous of the three. Fortunately, the earth’s ozone layer absorbs UV-C, and even higher-energy light is absorbed by atmospheric nitrogen, leaving UV-A and UV-B as the main concerns. The high-energy photons of UV light can penetrate the skin and trigger damaging reactions in DNA or excite chromophores to form reactive oxygen species (ROS).
Ninety-five percent of UV radiation that reaches the earth’s surface is UV-A. UV-A triggers tanning as the skin darkens in an attempt to protect itself. It plays a major role in skin aging, damages the epidermis, and contributes to skin cancer development.
Wavelength: 320–400 nm.
Effects: Tanning, premature skin aging, skin cancer.
Protection: Avobenzone (Parsol 1789), Ecamsule (Mexoryl), zinc oxide.
Wavelength: 290–320 nm.
Effects: Vitamin D production, sunburn, cataracts, genetic damage, skin cancer.
Protection: Oxybenzone, homosalate, octinoxate, octisalate, titanium dioxide.
Wavelength: 100–290 nm.
Effects: Cellular decomposition.
Protection: Ozone in the lower stratosphere.
A sunscreen’s efficacy is commonly indicated by its sun protection factor (SPF). SPF shows how long UV-B rays take to redden the skin; skin coated with SPF 15 sunscreen takes 15 times longer to redden than unprotected skin.
Infrared waves are part of the electromagnetic spectrum. Invisible to the eye, they are felt as heat. Remote controls, for example, use infrared light to change TV channels.
Sunscreens do not shield skin from infrared rays. Topical antioxidants may help, but evidence is limited. Ignore hype about infrared-blocking sunscreens.
Focus on broad-spectrum UV protection: use sunscreen, wear UPF 50 clothing and a sun hat, and seek shade. These steps keep skin healthy without controversy.
Daniel Barolet, François Christiaens, and Michael R Hamblin, Infrared and Skin: Friend or Foe, J Photochem Photobiol B. J Photochem Photobiol B. 2016 Feb; 155: 78–85.
Infrared and Skin: Friend or Foe
Laura Hudson, Eyman Rashdan, Catherine A. Bonn, Bhaven Chavan, David Rawlings, Mark A. Birch-Machin. Individual and combined effects of infrared, visible, and ultraviolet light from solar radiation on damage biomarkers in human skin cells. The FASEB Journal 2020; 34(3): 3874–3883. https://doi.org/10.1096/fj.201902351RR
