Updated: Aug 3, 2018
Sunscreen is a lotion, cream, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet (UV) radiation and prevents it from reaching the skin. Two types of ultraviolet radiation, UVA and UVB, damage the skin and increase your risk of skin cancer. Sunscreens vary in their ability to protect against UVA and UVB.
Ultraviolet (UV) radiation is part of the electromagnetic (light) spectrum that reaches the earth from the sun. It has wavelengths shorter than visible light, making it invisible to the naked eye. Ultraviolet A (UVA) is the longer wave UV ray that causes lasting skin damage, skin aging, and can cause skin cancer. Ultraviolet B (UVB) is the shorter wave UV ray that causes sunburns, skin damage, and can cause skin cancer
To combat this radiation there are two types of sunscreen available – Physical and Chemical. If the ingredients of sunscreen only contains zinc oxide or titanium dioxide, it’s a physical and it stays on top of the skin and deflect UV rays, While if the ingredient list includes octinoxate, homosalate, octocrylene, oxybenzone, octisalate, and/or avobenzone, these are UVA-protecting ingredients and are called Chemical which work by absorbing UV rays, reducing its penetration into the skin
These days most sunscreens have both Physical and Chemical Ingredients. It means in addition to UVA-Protecting ingredients, they also have zinc or titanium as an ingredient. These kind of sunscreens which protects from both UVA and UVB are known as broad spectrum sunscreens.
