Confused about the best sunscreen to use? Wondering whether sunscreen can be harmful? Lawrence Gibson, M.D., a dermatologist at Mayo Clinic, Rochester, Minn., offers his guidance.
What's the best way to sort through information about sunscreens?
Start by remembering the bigger picture when it comes to sun safety and what you can do to protect yourself. For example:
- Avoid the sun during peak hours. Generally, this is between 10 a.m. and 2 p.m. -- regardless of season. These are prime hours for exposure to skin-damaging ultraviolet (UV) radiation from the sun, even on overcast days.
- Wear protective clothing. This includes pants, shirts with long sleeves and sunglasses. Top it off with a wide-brimmed hat. Also, consider investing in sun-protective clothing or using an umbrella for shade.
- Use sunscreen. Apply sunscreen generously and reapply regularly.
Is there any truth to the claim that sunscreen use encourages excessive sun exposure and, as a result, increases the risk of skin cancer?
Most experts strongly disagree with this claim. Research also hasn't shown a link between sunscreen use and an increase in the risk of skin cancer. On the other hand, research has shown that use of sunscreen can reduce the risk of melanoma, the most serious type of skin cancer.
What does a broad-spectrum sunscreen do?
There are two types of UV light that can harm your skin -- UVA and UVB. A broad-spectrum, or full-spectrum, sunscreen is designed to protect you from both.
UVA rays can prematurely age your skin, causing wrinkling and age spots. UVB rays can burn your skin. Too much exposure to UVA or UVB rays can cause skin cancer. The best sunscreen offers protection from all UV light.
Does the best sunscreen also have the highest SPF?
SPF stands for sun protection factor, which is a measure of how well the sunscreen deflects UVB rays. Manufacturers calculate SPF based on how long it takes to sunburn skin that's been treated with the sunscreen as compared with skin that hasn't been treated with sunscreen.
Theoretically, the best sunscreen has the highest SPF number. It's not that simple, however. When applied correctly, a sunscreen with an SPF of 30 will provide slightly more protection from UVB rays than does a sunscreen with an SPF of 15. But the SPF 30 product isn't twice as protective as the SPF 15 product. Sunscreens with SPFs greater than 50 provide only a small increase in UVB protection.
Also, keep in mind that sunscreen is often not applied thoroughly or thickly enough, and it might be washed off during swimming or sweating. As a result, even the best sunscreen might be less effective than the SPF number on the bottle would lead you to believe.
Rather than looking at a sunscreen's SPF, choose a broad-spectrum sunscreen that will protect you from UVA and UVB rays.
What do I need to know about sunscreen ingredients?
Sunscreens contain filters that reflect or absorb UV rays. There are two main types of sunscreens:
- Organic. Also called chemical sunscreens, organic sunscreens absorb UV radiation and convert it to a small amount of heat. This group of active ingredients is the most widely used in sunscreens. Organic sunscreens might contain avobenzone, cinoxate, ecamsule, menthyl anthranilate, octyl methoxycinnamate, octyl salicylate, oxybenzone or sulisobenzone.
- Inorganic. Also called physical sunscreens, inorganic sunscreens reflect and scatter UV radiation. Inorganic sunscreens might contain titanium dioxide or zinc oxide. Most broad-spectrum sunscreens use both ingredients to better block UVA and UVB rays.
Sunscreens also might contain:
- Vitamins. Vitamin E can protect against UV-induced DNA damage. Vitamin C helps protect skin from sunburn.
- Insect repellent. Keep in mind that it's typically recommended that insect repellent be applied no more often than every six hours. When using this type of combination product, reapply a sunscreen without insect repellent after two hours outdoors or after swimming or heavily sweating.
Some sunscreens also contain the antioxidant retinyl palmitate, a form of vitamin A or retinol. Antioxidants are substances that neutralize free radicals — unstable oxygen molecules that break down skin cells and cause wrinkles. While concerns have been raised about sunscreens containing retinyl palmitate, research currently suggests it's safe. However, recommendations regarding safety for use during pregnancy aren't available. If you're concerned, consider avoiding sunscreens containing this ingredient during pregnancy.
Are some brands of sunscreen better than others?
Brand matters less than how you use the product. In general, look for water-resistant, broad-spectrum coverage with an SPF of at least 15. Check the sunscreen's expiration date, and follow the directions on the label.
Also, keep in mind that labeling guidelines for sunscreen in the United States are changing. Under new Food and Drug Administration guidelines:
- Only sunscreens that offer protection from both UVA and UVB rays can advertise broad-spectrum coverage on the label.
- Only broad-spectrum sunscreens with an SPF of 15 or higher can claim to reduce the risk of skin cancer or prevent early skin aging.
- Any claims about reducing the risk of skin cancer or early skin aging must be accompanied by other sun protection measures, such as wearing protective clothing and avoiding midday sun.
- Sunscreens with an SPF of at least 2 but less than 15 can advertise protection from sunburn only -- not protection from skin cancer or early skin aging.
- Sunscreens can't be advertised as sweatproof or waterproof.
- Sunscreens that pass a water resistance test can be labeled "water resistant" for either 40 or 80 minutes, as long as they also include instructions to reapply after 40 or 80 minutes of swimming or sweating, immediately after towel drying and at least every two hours.