Physical vs. Chemical sunscreens
Confused by what sunscreen to buy? You're not alone. Gundersen dermatologist April Farrell, MD, says knowing what to look for in a sunscreen can make this task much easier. She offers this helpful overview.
Many of today's sunscreens contain both physical and chemical UV filters. To make sure your sunscreen offers the best protection, look for "broad spectrum" protection and an SPF of 30-50.
Broad spectrum means you're screening out both ultraviolet A (UVA) rays, which cause premature aging, wrinkling and skin cancer, and ultraviolet B (UVB) rays, which cause sunburn.
Most importantly, says Dr. Farrell, "A sunscreen only works if you wear it, apply enough of it and remember to reapply every 90 to 120 minutes, or after being in water."
Physical or mineral sunscreen (sunblock)
Ingredients such as zinc oxide and titanium dioxide protect your skin by deflecting or blocking the sun's rays.
- Zinc oxide provides broad protection against both UVA and UVB light
- Starts protecting right after applying—no need to wait before going in the sun
- Better tolerated by most skin types
- Lasts longer in the sun
- May not offer as much UVA protection compared to chemical sunscreens
- Thicker cream may be more difficult to apply and may leave white residue on skin
- Harder to find in stores and usually more expensive
Chemical filters like Avobenzone, Octinoxate, Octisalate, Octocrylene and Oxybenzone work by absorbing the UV rays before they reach the skin.
- Generally more coverage against UVA and UVB rays, but range of protection depends on ingredients
- Readily available and usually cheaper
- Easier to apply and invisible when applied
- May be more irritating for some people—can cause allergic reactions
- Must wait 20 minutes after applying for effective sun protection
- Starts degrading in sunlight, so need to reapply more often