Sunscreen 101: What You Need to Know to Protect Your Skin

Used year-round, the right sunscreen can protect your delicate skin from the sun's harmful rays

by Darrell Gonzales, MD

It’s that time of year again — sunscreen displays are front and center in pharmacies and department stores. There seems to be a formula for every skin type: infant, aging, fair, dark, sensitive and so on.

If you’re not sure what to look for, trying to choose the right sunscreen can be overwhelming. We’ve put together easy-to-use guidelines to help you decipher sunscreen label information and find the product that gives you the sun protection you need.

Who needs sunscreen?

Everyone. According to the American Cancer Society, more than 1 million new cases of skin cancer will be diagnosed in the United States this year. Sunscreen reduces your exposure to ultra-violet light that has been shown to induce skin cancer. All persons, regardless of skin type, should be wearing at least a broad spectrum sunscreen with a Sun Protection Factor (SPF) of at least 15 daily.

What does “broad spectrum” mean?

Sunlight contains two types of harmful rays — ultraviolet A (UVA) and ultraviolet B (UVB). UVB rays are the ones that can cause sunburn. UVA rays, which penetrate deeper into the skin than UVB rays, can lead to premature aging of the skin and also may suppress the immune system, which in turn can increase your risk of developing skin cancer.

UVB rays cannot pass through glass (such as car windows), but UVA rays can. Overexposure to either type of ray can lead to skin cancer; a “broad spectrum” sunscreen protects against both.

Sunscreen: What to look for

In order to achieve broad spectrum coverage, make sure your sunscreens contain a combination of some of the ingredients below:

  • UVB

    • octyl methoxycinnamate
    • octyl salicylate
  • UVA

    • avobenzone (Parsol 1789)
    • oxybenzone
    • ecamsule (Mexoryl SX)
    • menthyl anthranilate

    • cinoxate
    • sulisobenzone

Alternatively, you can purchase a sunscreen containing a broad spectrum physical blocker, such as zinc oxide or titanium dioxide. These can be convenient for individuals who have sensitive skin or are allergic to other sunscreens. A tint in the physical blockers can reduce the white opaque look.

Recently, the American Academy of Dermatology introduced the AAD SEAL OF RECOGNITION™ which is designed to help consumers choose products that will provide the sun protection recommended by dermatologists, including broad spectrum, water-resistant sunscreens with a Sun Protection Factor (SPF) of 15 or higher. Look for the AAD SEAL OF RECOGNITION™ symbol and statements on product labels.

What Sun Protection Factor (SPF) do I need?

Sunscreens absorb or reflect the sun’s rays so they don’t harm your skin. The SPF indicates how much longer you can stay in the sun without burning than you could with unprotected skin. For example, if it takes 15 minutes for a person to burn without sunscreen, an SPF 15 will theoretically allow him or her to stay in the sun 15 times longer without burning.

SPF numbers range from 2 to more than 70; the higher the number, the more protection a sunscreen provides, but anything containing SPF of greater than 30 provides only slightly incremental benefits.

Everyone should use an SPF of at least 15 for routine daily wear, even on overcast days — up to 80 percent of the sun’s burning rays pass through clouds. This holds true for both darker and lighter complexions. If you plan to be in the sun for an extended period, you should wear a sunscreen with at least SPF 30 and reapply every two hours.

If you are swimming or surfing, reapply sunscreen even more often. A sunscreen that is “waterproof” should provide protection in the water for 80 minutes; a “water- resistant” product should protect for 40 minutes. You really can’t use too much sunscreen, so err on the side of caution.

Cream, gel, stick, spray — which should I use?

If you have specialized skin care concerns such as sensitive skin, want an anti-aging benefit or require a product specifically made for a baby’s delicate skin, choose a product specially formulated for your needs. Otherwise, it’s really a matter of personal preference.

If you have dry skin, you may find a cream is more moisturizing than a gel. Some people prefer the ease of a spray. Many face and body lotions and cosmetics now contain sunscreen, so you may be able to use just one product instead of two.

Regardless of the type of sunscreen you use, be sure to apply it liberally to all exposed areas, especially your face, ears, feet and hands. If you’re using a cream or gel, a good general guideline is to use one ounce of product — about what you’d need to fill a shot glass. Apply it to dry skin about 30 minutes before you head outside to give the chemicals time to form a barrier between your skin and the sun.

Does sunscreen expire?

The FDA requires that all sunscreens be stable and at their original strength for at least three years. However, if you are using the correct amount, a bottle of sunscreen probably shouldn’t last more than a few months.

Even if you use sunscreen religiously, get a skin check form your doctor or dermatologist at least once a year to catch any suspicious moles, spots or other abnormalities before they become a problem. In its earliest stages, skin cancer is highly treatable.

This Scripps Health and Wellness information was provided by Darrell Gonzales, MD, dermatologist with Scripps Memorial Hospital La Jolla.