Sunscreen refers to any number of different compounds, chemicals, or other substances that slow the sun’s damaging effects on human skin. All sunscreen products contain specific ingredients designed to protect against UV radiation and potential heat-related erythema (skin redness). Humans have used the sun’s rays to cure many diseases for thousands of years, yet it is only recently that we have recognized its dangers. Sunscreen was only developed in the 20th century.
How it works:
Sunscreens work by either absorbing, reflecting, or scattering harmful UVA and UVB rays. They are absorbent when they interact with the skin. Sunscreen is usually a white or colored liquid, but can also be in the form of an ointment, cream, lotion, or gel. The most common ingredients in sunscreen include zinc oxide (ZnO), titanium dioxide (TiO2), and/or oxybenzone (benzophenone-3).
Zinc oxide and titanium dioxide are considered physical blockers because they don’t break down from UV exposure, but instead, create a barrier that protects skin by reflecting and scattering the sun’s rays. Zinc oxide is a smooth white substance, while titanium dioxide is not colorless or odorless. Oxybenzone absorbs UV radiation and helps other sunscreen ingredients work better. There are also chemical blockers such as avobenzone and Mexoryl SX. Chemical blockers break down in sunlight but work faster than physical blockers.
How to use it:
It is important to remember that sunscreen needs time to work. It may take up to two hours for the substance to become effective when applied before going outside. In addition, you must reapply the sunscreen frequently enough so that it doesn’t wash off or run into your eyes. It is also important not to use too much as this could lead to allergic reactions. Adults should use about a teaspoon of sunscreen, and children should use one-fourth to one-half teaspoon. It is also recommended that you apply sunscreen to all exposed skin, including the lips, nose, ears, and any other skin that is exposed to light.
What are the concerns:
Many experts warn against frequent or prolonged use of sunscreen because they believe it may cause vitamin D deficiency.
