We are going to have a severe scorching summer. Although it has not been a practice to apply sunscreens in this part of the world, in western civilizations it is a common practice though they have summer that is not too severe and not for long. Applying sunscreen is a practice to avoid sunburn and skin cancers due to exposure to excessive UV rays. Do you know the chemistry behind sunscreen based skin protection? We have to know how a sunscreen lotion works or what is an SPF rating? SPF stands for Sun Protection Factor.

Excessive UV rays produce mutations in our DNA that can lead to skin cancer/melanoma. Sunscreens usually are lotions that contain organic constituents (oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate) and inorganic chemicals (metal oxides) that filter the radiation from the sun and ensure less UV rays reach deeper layers of our skin. Metal Oxides, referred as sunblocks (Zinc oxide and Titanium oxides), reflect light away so that UVA and UVB rays do not reach the skin.

The SPF factor written on the lotion containers helps you decide what temperatures you face, duration of your stay in sun and how much protection you require. Sunburns are usually caused by UV-B radiation, and UV-A radiation results in genetic mutations due to which cancer and premature aging of the skin occur. Our skin has a natural chemical called melanin, which determines skin pigmentation and offers us limited protection from sun light. Hence, if you are a person who takes good care of your skin and require protection, look out on the sunscreen container for protection from UV-A and UV-B radiation. If you are further interested in knowing about these chemicals or their mechanisms of protection, please refer to the below journal article: Reference: Sunscreening Agents, a review: J Clin Aesthet Dermatol. 2013 Jan; 6(1): 16–26.

Contributed by: Dr. Ramars Amanchy, CSIR-IICT, Hyderabad.