Sunblock and sunscreen are two very different types of sun protection.

Sunscreen is a chemical defense, penetrating the skin and absorbing the UV rays before they reach and damage the skin cells.

Sunblock is a physical way to defend against ultraviolet (UV) rays. It rests on the skin’s surface, shielding against and absorbing UV light. Typically, sunblock includes zinc oxide or titanium dioxide. Sunblocks are often opaque and noticeable when applied to the skin.

Many brands of sun protection offer a blend of sunscreen and sunblock.

Both sunscreen and sunblock provide protection from the sun.

For people with sensitive skin, sunblocks with zinc oxide and titanium dioxide may be better tolerated. These ingredients are also typically found in products for children, who have different sun protection needs.

People with skin conditions, such as rosacea or allergy-prone skin, may want to avoid products that contain fragrances, preservatives, and oxybenzone or PABA, which are often found in sunscreens.

The Environmental Working Group has also cautioned against use of sun protectants with oxybenzone, as it may cause an allergic reaction.

Before trying a new sunscreen or sunblock, read the label to make sure you’ll get the protection you need and avoid ingredients you may be sensitive to.

Many doctors recommend sun protectants that offer:

Many sun protectants have a combination of sunscreen and sunblock, so consider taking the time to review the label before purchasing and applying the product.

Look for products that are SPF 30 or greater, have broad spectrum protection, and are water resistance. Avoid any products that contain ingredients your skin may be sensitive to.

To prevent burning, reapply sun protectants every two hours, or every 40 to 80 minutes after being in the water or sweating.