Most of us shop for sunscreen every year. But do you know what to look for? While the best sunscreen for you is whichever one you’ll always use when you’re outside, the American Academy of Dermatology (AAD) recommends you choose sunscreen with broad-spectrum protection, SPF 30 or higher, and water resistance. A broad-spectrum sunscreen is designed to help you combat skin cancer, sunburns, and early skin aging.
What does SPF mean and what should I look for?
Sun Protection Factor (SPF) measures how well the sunscreen protects your skin against sunburn. Specifically, the SPF indicates how long a typical person who applies sunscreen can stay in the sun before UVB rays start to burn the skin compared to how long it takes for the skin to start reddening without sunscreen. No sunscreen can block 100 percent of the sun’s UVB rays, although lab tests suggest how much UVB light different SPFs can filter out:
- SPF 15 – 93 percent of UVB rays
- SPF 30 – 97 percent of UVB rays
The AAD advises always using an SPF 30 or higher. Keep in mind, above SPF 50 the amount of additional protection is marginal. And sunscreens lose effectiveness over time – you should reapply every two hours.
If I plan on being in the water, which sunscreen should I pick?
You’ll need to reapply sunscreen more frequently when you’ve been in the water or sweating. No sunscreen is fully “waterproof” or “sweatproof,” so look for these terms:
- Water resistant – effective for 40 minutes in the water
- Very water resistant – effective for 80 minutes in the water
That means after 40 or 80 minutes, you’ll need to reapply. And even if your skin stays dry, reapply it every two hours anyway.
What else should I look for on a sunscreen label?
Sunscreen products are considered over-the-counter drugs by the FDA, which regulates what their labels can say. In addition to whether the sunscreen is broad spectrum or water resistant and what its SPF is, look for the Skin Cancer Foundation Seal of Recommendation. A non-profit organization, the Skin Cancer Foundation conducts two non-FDA tests for allergic reactions and rashes through contact irritancy, and phototoxicity, which shows up after UV exposure. Check sunscreen labels for one of these:
- Daily use seal – for short sun exposure, like walking to your car, going to work or running errands
- Active seal – for longer periods of time outside, like exercising in the sun or hanging out at the beach
What are active ingredients in sunscreen that protect skin?
There are two main types of sunscreen ingredients that actively protect your skin:
- Chemical – such as avobenzone and benzophenone, which absorb UV rays to reduce how much penetrates the skin
- Physical – such as titanium dioxide and zinc oxide, which deflect and scatter UV rays
Many sunscreens combine both types to give you the greatest protection. Some people prefer sunscreens with physical ingredients, which can be less irritating to sensitive skin.
Whether you choose a product that’s a lotion, cream, gel, ointment, stick or spray, be sure to completely and evenly cover all exposed skin – and reapply regularly. Then enjoy your time in the sun!
Carolyn Langer, MD, JD, MPH, is the clinical leader and chief medical officer for Wellpoint (formerly UniCare), a health benefits company based in Woburn, Mass. She is board-certified in occupational medicine.