Sunscreen

Formulated with ingredients to protect your skin from harmful ultraviolet (UV) rays, sunscreen is a must for anyone who spends time outdoors. Exposure to the sun increases your risk for skin cancer. Although sunscreen doesn't offer complete protection from all skin cancers, experts say most brands offer invaluable protection against UVB radiation — the part of the ultraviolet spectrum that causes tanning and burning.

Key Features of Sunscreens

To choose an appropriate sunscreen, it's important to know your skin type and the conditions under which the sunscreen will be used. The lighter your skin or the greater your exposure to the sun, the more protection you'll need. Here are some terms to know when comparing products:

SPF

The ability of sunscreen to block UVB rays is measured by a rating called an SPF, or sun protection factor. The higher the rating, the longer a sunscreen protects against sunburn. The American Academy of Dermatology recommends sunscreens with an SPF of 15 or higher to help prevent burning and reduce your long-term risk for some skin cancers. If you're extremely fair-skinned and burn easily, consider a product with an SPF of at least 30.

Broad-spectrum

SPF doesn't measure a product's ability to block UVA rays, which can also damage skin. To block both UVB and UVA rays, look for products that promise "broad spectrum" protection. Commonly used ingredients that block UVA include avobenzone, titanium oxide, and zinc oxide.

Hypoallergenic

Some ingredients in sunscreen, for example PABA or ingredients used for fragrance, can irritate some people's skin. Products formulated to minimize skin irritation may be labeled hypoallergenic, non-allergenic, dermatologist tested, PABA-free, or fragrance-free. The truth is, there's no way to know how your skin will react to a sunscreen until you apply it.

Waterproof and water resistant

Many of the sunblocking ingredients in sunscreen wash off easily in water. A waterproof formula should retain its effectiveness for up to 80 minutes in the water. A water-resistant product should maintain its SPF up to 40 minutes in the water.

Sweatproof

Sweatproof or "sport" sunscreens promise not to drip into your eyes when you perspire.

Non-comedogenic

Products that claim to be non-comedogenic or oil-free may not clog pores.

How to Use Sunscreens

Sunscreens won't work if not applied as directed on the label. Some guidelines for use:

Shake well before using. The particles in some sunscreens tend to clump.
To test for an allergic response, apply a small amount of sunscreen to a small portion of your skin a day before you plan to use the product. If your skin doesn't become irritated, then the sunscreen is probably fine for you.
Use enough to thoroughly cover exposed skin. For adults in bathing suits that means using about an ounce, or a generous handful.
Apply at least a half hour before going outside. Rub it in well to ensure that the sunscreen is thoroughly absorbed.
Reapply as directed. Generally, you'll need to put on some additional sunscreen if you remove the first application by swimming, sweating, or toweling off.