The experts agree: One of the best ways to prevent further skin damage is to wear sunscreen daily. "Even if you once worshipped the sun and didn't protect your skin, it's worth using sunscreen now," says Dee Anna Glaser, MD, associate professor of dermatology at Saint Louis University.

Sunscreen won't reverse wrinkles or spots caused by the sun, but when used consistently, it helps reduce further cellular damage that, if left unchecked, can lead to more sun-induced symptoms, including skin cancer, says Glaser. Here, need-to-know info:

Read the label: Seek out sunscreens that contain micronized zinc oxide or titanium dioxide. Both of these physical blockers coat the skin and create a barrier against harmful ultraviolet A and B rays, both of which are now known to play a role in sunburn, aging the skin and the risk of skin cancer.

Zinc oxide rubs into the skin easily, making it more cosmetically pleasing than titanium dioxide, which may leave a whitish glow. Parsol 1789, a chemical blocker that protects skin by absorbing UV light, is also a powerful protector, but it may cause skin irritation or allergic reactions in some people.

Wear it well: UV rays are constant, so apply sunscreen to exposed skin (SPF 15 or higher) year-round, even on days when you're not going to the beach or playing golf. If you use a face moisturizer with blockers, one teaspoon will do the job.

When you're outside wearing shorts, a T-shirt or swimwear, one ounce (a shot-glass full) should cover the average person. Last Updated: 2006-06-20