The number of options on store shelves can make choosing sunscreen a confusing task. If you’re not familiar with sunscreen lingo, reading the label may not be much help.
Dr. Thomas McIntee, a Marshfield Clinic pediatric dermatologist, explained what to look for on labels to best protect your skin from the sun.
New lingo: Organic vs. inorganic sunscreen
Sunscreen labeled organic doesn’t mean its ingredients were grown on a farm without pesticides. Organic sunscreens are made of carbon-based ingredients that absorb into the skin. They absorb UV light and disperse it as heat. Some common organic ingredients you’ll see on labels end in -benzone or -cinnamate. These ingredients sometimes are called chemical blockers.
Inorganic is the new term for the physical blockers zinc and titanium dioxide. These ingredients reflect UV light and tend to have a better UV-blocking spectrum than organic products. They stay on top of the skin but are now made to leave less white residue.
Which should you choose?
“It’s best to look for a broad-spectrum sunscreen that protects against UVB rays that cause sunburns and UVA rays that cause skin aging,” McIntee said. “Broad spectrum sunscreens usually have a mix of organic and inorganic blockers.”
Organic sunscreens are more likely to trigger a sun allergy. Inorganic sunscreen is best for young children and people with sensitive skin. Babies younger than 6 months should stay out of the sun or wear protective clothing, but inorganic sunscreen is best if your baby must be in the sun.
The science of SPF
Sun protection factor (SPF) refers mostly to UVB protection, or how well sunscreen protects skin from burns. Some other parts of the world label sunscreen strength differently. McIntee recommends using products with SPF ratings to avoid confusion.
Higher SPF means more protection, but SPF 100 isn’t twice as good as SPF 50. SPF 15 blocks 93 percent of UVB radiation, while SPF 50 blocks 98 percent. McIntee recommends using at least SPF 30.
“No sunscreen blocks 100 percent of UV rays,” McIntee said. “Shade and protective clothing add extra sun protection.”
Water-resistant doesn’t mean waterproof
Sunscreen labeled water-resistant or sweat-resistant still wears off wet or damp skin. No sunscreen is waterproof.
Water-resistant sunscreen lasts 40 minutes in the water before you need to reapply. Sunscreen labeled very water-resistant lasts 80 minutes. Skin should be dry before reapplying sunscreen so it doesn’t slip off.
Inorganic sunscreen is the best bet for kids who are eager to get back in the water after it’s reapplied. Organic sunscreen needs 20 minutes to absorb before you can swim again.
Proper use is most important
“The biggest reason sunscreen fails is that people don’t use enough or apply it as frequently as they should,” McIntee said.
Use teaspoon-size amounts on each section of your body – one for your head and neck, one each for your chest, back and arms and two for each leg. Sunscreen breaks down in the sunlight and needs to be reapplied every two hours.
Finally, remember that sunscreen becomes less effective when it expires. Check the expiration date and throw out old products. If you can’t find an expiration date, label the bottle with the purchase date and throw away after three years. Keep sunscreen in a cool place away from UV light.