Can Skin Cancer Be Prevented?


People who get a lot of exposure to ultraviolet (UV) rays are at greater risk of skin cancer.

Sunlight is the main source of UV rays, but you don’t have to avoid the sun completely. And it would be unwise to stay inside if it would keep you from being active, because physical activity is important for good health. But getting too much sun can be harmful. There are some steps you can take to limit your exposure to UV rays.

Some people think about sun protection only when they spend a day at the lake, beach, or pool. But sun exposure adds up day after day, and it happens every time you are in the sun.

Simply staying in the shade is one of the best ways to limit your UV exposure. If you are going to be in the sun, “Slip! Slop! Slap!® and Wrap” is a catchphrase that can help you remember some of the key steps you can take to protect yourself from UV rays:

  • Slip on a shirt.
  • Slop on sunscreen.
  • Slap on a hat.
  • Wrap on sunglasses to protect the eyes and skin around them.

How Do I Protect Myself from UV Rays?

Seek Shade

An obvious but very important way to limit your exposure to UV light is to avoid being outdoors in direct sunlight too long. This is particularly important between the hours of 10 am and 4 pm, when UV light is strongest. If you are unsure how strong the sun’s rays are, use the shadow test: if your shadow is shorter than your are, the sun’s rays are the strongest, and it’s important to protect yourself.

UV rays reach the ground all year, even on cloudy or hazy days, but the strength of UV rays can change based on the time of year and other factors. UV rays become more intense in the spring, even before temperatures get warmer. People in some areas may get sunburned when the weather is still cool because they may not think about protecting themselves if it’s not hot out. Be especially careful on the beach or in areas with snow because sand, water, and snow reflect sunlight, increasing the amount of UV radiation you get. UV rays can also reach below the water’s surface, so you can still get a burn if you’re in the water and feeling cool.

Some UV rays can also pass through windows. Typical car, home, and office windows block most UVB rays but a smaller portion of UVA rays, so even if you don’t feel you’re getting burned your skin may still get some damage. Tinted windows help block more UVA rays, but this depends on the type of tinting. (If you do have your car windows tinted, check local laws, as some states regulate this.) UV radiation that comes through windows probably doesn’t pose a great risk to most people unless they spend long periods of time close to a window that gets direct sunlight.

If you plan to be outdoors, you may want to check the UV Index for your area. The UV Index usually can be found in local newspaper, TV, radio, and online forecasts. It’s also on the EPA’s website and in many smartphone apps (see

Protect Your Skin with Clothing

When you are out in the sun, wear clothing to cover as much skin as possible. Clothes provide different levels of UV protection. Long-sleeved shirts, long pants, or long skirts cover the most skin and are the most protective. Dark colors generally provide more protection than light colors. A tightly woven fabric protects better than loosely woven clothing. Dry fabric is generally more protective than wet fabric.

Be aware that covering up doesn’t block out all UV rays. If you can see light through a fabric, UV rays can get through, too.

Some companies now make clothing that’s lightweight, comfortable, and protects against UV exposure even when wet. It tends to be more tightly woven, and some have special coatings to help absorb UV rays. These sun-protective clothes may have a label listing the UV protection factor (UPF) value (the level of protection the garment provides from the sun’s UV rays, on a scale from 15 to 50+). The higher the UPF, the higher the protection from UV rays.

Newer products, which are used like laundry detergents in a washing machine, can increase the UPF value of clothes you already own. They add a layer of UV protection to your clothes without changing the color or texture. This can be useful, but it’s not exactly clear how much it adds to protecting you from UV rays, so it’s still important to follow the other steps listed here.

Use Sunscreen

Sunscreen is a product that you put on your skin to protect it from the sun’s UV rays. But it’s important to know that sunscreen is just a filter — it does not block all UV rays. Sunscreen should not be used as a way to prolong your time in the sun. Even with proper sunscreen use, some UV rays get through, which is why using other forms of sun protection is also important.

Sunscreens are available in many forms — lotions, creams, ointments, gels, sprays, wipes and lip balms, to name a few.

Some cosmetics, such as moisturizes, lipsticks, and foundations, are considered sunscreen products if they have sunscreen. Some makeup contains sunscreen, but you have to check the label — makeup, including lipstick, without sunscreen does not provide sun protection.

Read the Labels

When choosing a sunscreen product, be sure to read the label. Sunscreens with broad spectrum protection (against both UVA and UVB rays) with sun protection factor (SPF) values of 30 or higher are recommended.

Sun Protection Factor (SPF)

The SPF number is the level of protection the sunscreen provides against UVB rays, which are the main cause of sunburn. A higher SPF number means more UVB protection (although it says nothing about UVA protection). For example, when applying an SPF 30 sunscreen correctly, you get the equivalent of 1 minute of UVB rays for each 30 minutes you spend in the sun. So, 1 hour in the sun wearing SPF 30 sunscreen is the same as spending 2 minutes totally unprotected. People often do not apply enough sunscreen, so they get less actual protection.

Sunscreens labeled with SPFs as high as 100+ are available. Higher numbers do mean more protection, but many people don’t understand the SPF scale. SPF 15 sunscreens filter out about 93% of UVB rays, while SPF 30 sunscreens filter out about 97%, SPF 50 sunscreens about 98%, and SPF 100 about 99%. The higher you go, the smaller the difference becomes. No sunscreen protects you completely.

Sunscreens with an SPF lower than 15 must now include a warning on the label stating that the product has been shown only to help prevent sunburn, not skin cancer or early skin aging.

Broad Spectrum Sunscreen

Sunscreen products can only be labeled “broad spectrum” if they have tested and shown to protect against both UVA and UVB rays. Some of the chemicals in sunscreens that help protect against UVA rays include avobenzone (Parsol 1789), ecamsule, zinc oxide, and titanium dioxide.

Only broad spectrum sunscreen products with an SPF of 15 or higher can state that they help protect against skin cancer and early skin aging if used as directly with other sun protection measures.

Water Resistant Sunscreen

Sunscreens are no longer allowed to be labeled as “waterproof” or “sweatproof” because these terms can be misleading. Sunscreens can claim to be “water resistant,” but they have to state whether they protect the skin for 40 or 80 minutes of swimming or sweating, based on testing.

Expiration Dates

Check the expiration date on the sunscreen to be sure it’s still effective. Most sunscreen products are good at least 2 to 3 years, but you may need to shake the bottle to remix the sunscreen ingredients. Sunscreens that have been exposed to heat for long periods, such as if they were kept in a glove box or car trunk through the summer, may be less effective.

Wear a Hat

A hat with at least a 2- to 3-inch brim all around is ideal because it protects areas that are often exposed to intense sun, such as the ears, eyes, forehead, nose, and scalp. A dark, non-reflective underside to the brim can also help lower the amount of UV rays reaching the face from reflective surfaces such as water. A shade cap (which looks like a baseball cap with about 7 inches of fabric draping down the sides and back) also is good, and will provide more protection for the neck. These are often sold in sports and outdoor supply stores. If you don’t have a shade cup (or another good hat) available, you can make one by wearing a large handkerchief or bandana under a baseball cap.

A baseball cap protects the front and top of the head but not the neck and ears, where skin cancers commonly develop. Straw hats are not as protective as hats made of tightly woven fabric.

Wear Sunglasses that Block UV Rays

UV-blocking sunglasses are important for protecting the delicate skin around the eyes, as well as they eyes themselves. Research has shown that long hours in the sun without protecting your eyes increase your chances of developing certain eye diseases.

The ideal sunglasses should block 99% to 100% of UVA and UVB rays. Before you buy, check the label to make sure they do. Labels that say “UV absorption up to 400 mm” or “Meets ANSI UV Requirements” mean the glasses block at least 99% of UV rays. Those labeled “cosmetic” block out about 70% of UV rays. If there is no label, don’t assume the sunglasses provide any UV protection.

Darker glasses are not necessarily better because UV protection comes from an invisible chemical in or applied to the lenses, not from the color or darkness of the lenses. Look for an ANSI label.

Large-framed and wraparound sunglasses are more likely to protect your eyes from light coming in from different angles. Children need smaller versions of real, protective adult sunglasses — not toy sunglasses.

Ideally, all types of eyewear, including prescription glasses and contact lenses, should protect against UV rays. Some contact lenses are now made to block most UV rays. But because they don’t cover the whole eye and surrounding areas, they are not sufficient eye protection when used alone.

What About Tanning Pills and Other Tanning Products?

Several products claim to give a tan without exposing a person to ultraviolet (UV) radiation. Some may be safe and effective, but others might not work, and some could even be harmful.

Tanning Pills and Accelerators

Tanning pills contain color additives similar to beta-carotene, the substance that gives carrots their orange color. Once swallowed, the additives are deposited throughout the body, especially the skin, turning it an orange-like color. Although the US Food and Drug Administration (FDA) has approved some of these additives for coloring food, they are not approved for use in tanning agents. They may be harmful at the high levels that are used in tanning pills. The main ingredient in most sunless tanning pills, canthaxanthin, can show up in your eyes as yellow crystals, which may cause injury or impair vision. There have also been reports of liver and skin problems.

Tanning accelerators, such as lotions or pills that contain the amino acid tyrosine or its derivatives, do not work and may be dangerous. Marketers say these products stimulate the body’s own tanning process, but most evidence suggest they don’t work. The FDA considers them unapproved new drugs that have not been shown to be safe and effective.

No tanning pills have been approved by the FDA.

Bronzers and Extenders

Two other sunless tanning products, bronzers and extenders, are considered cosmetics for use on the skin. They are not thought to be harmful when used properly.

Bronzers, made from color additives approved by the FDA for cosmetic use, stain the skin for a short time when applied and can be washed off with soap and water.

Extenders (also known as sunless tanners or self-tanners) are applied to the skin as lotions or creams, where they interact with proteins on the surface of the skin to produce a darker color. Like a tan, the color tends to wear off after a few days. The only FDA-approved color additive for extenders is dihydroxyacetone (DHA).

Applying these products by hand can sometimes lead to uneven coloring, so some tanning salons have begun to offer whole body sprays in tanning booths. A concern here is that DHA is approved for external use only and should not be inhaled or sprayed in or on the mouth, eyes, or nose. People who choose to get a DHA spray tan should make sure to protect these areas.

These products can give skin a darker color (although in some people it may have a slight orange tinge), but they don’t offer much protection from the damaging effects of UV radiation. Even if they contain sunscreen, it would only be effective for a couple of hours. You should read the label carefully to determine whether or not a product provides and protection, but in most cases it’s safest to continue to use sunscreen and wear protective clothing when going outside.


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