More sunscreen isn't always better, dermatologists say — here are the mistakes you're making

Sunscreen is considered essential for protecting skin from intense summer UV rays. Yet many people fail to apply enough — or reapply on time — and end up with far less protection than they expect.

The New York Times on June 25 outlined proper sunscreen use based on recommendations from the American Academy of Dermatology (AAD) and other experts.

Experts say the most effective way to prevent UV damage is to avoid direct sunlight in the first place. Since that is rarely practical in daily life, however, they said the most realistic approach is to combine sunscreen with sunglasses, a wide-brimmed hat and UV-protective clothing.

Any sunscreen that has not expired, carries a "broad spectrum" label blocking both UVA and UVB rays, and has an SPF of 30 or higher is sufficient. Because people tend to apply less than the recommended amount in practice, however, choosing SPF 50 or above can help compensate. A higher SPF number does not mean reapplication can be delayed — all sunscreens must be reapplied at least every two hours.

The amount applied also matters. Adults need about 30 milliliters — roughly two tablespoons — to cover the entire body. For the face alone, a coin-sized amount is enough to cover the face, neck and ears.

Stick and spray sunscreens are convenient but must be rubbed in thoroughly by hand after application. Stick formulas should be applied by going back and forth over each area several times, then spread evenly with the fingers. Sprays should be misted on until the skin looks visibly wet, then rubbed in immediately. For the face, experts recommend spraying into the hands first rather than applying directly to the face.

The ears and tops of the feet are among the most commonly missed spots. Research also suggests that hard-to-reach areas like the back are covered more effectively with another person's help.

Sunscreen should be applied 15 to 20 minutes before going outside to allow time for absorption. It should then be reapplied after swimming, after heavy sweating, or once one to two hours have passed. Experts advise applying once before heading out and again within the first hour of sun exposure to reduce the chances of forgetting to reapply.

The scalp also needs protection when exposed to the sun. A hat is the best option, but face sunscreen can be used on the scalp if necessary. Sunscreen does not need to be applied over a full beard that completely covers the skin beneath.

Regardless of which type of sunscreen is used, experts said the most important factors are applying a sufficient amount, covering all exposed areas and reapplying regularly. Since sunscreen alone cannot block all UV radiation, they said combining it with physical barriers such as hats and protective clothing is the most effective way to protect the skin.