Sunscreen Explained: How Chemistry Protects Your Skin

Sunscreens use UV filters that either absorb, reflect, or scatter harmful ultraviolet light.
Organic filters like oxybenzone absorb UV rays and convert them into harmless heat.
Inorganic filters such as zinc oxide and titanium dioxide act like tiny shields, reflecting UV rays.
SPF (Sun Protection Factor) measures how much longer sunscreen protects you compared to bare skin.
Broad-spectrum formulas block both UVA rays (aging) and UVB rays (burning).
Free radical damage is reduced when sunscreens prevent UV-induced DNA changes.
Water-resistant sunscreens use special binders to stay effective during swimming or sweating.
Photostability matters—some filters break down in sunlight, so stabilizers are added.
Antioxidants like vitamin E are often included to boost skin defense against oxidative stress.
Reapplication every 2 hours is key because sunscreen wears off through sweat, water, and time.