Sunscreen: Your Most Important Weapon Against Skin Cancer

As the weather warms, many people—especially parents—will begin stocking up on sunscreen to protect against sunburns. However, sunscreen does more than provide a safeguard against rashes and peeling: It's also a first-line defender against skin cancer.

When did people first use sunscreen?

The practice of shielding our skin from the sun has a long history. Initially, hats and scarves were the primary means of protection. Ancient Greeks introduced olive oil to protect their skin against sun exposure and to add moisture. Of course, we now know olive oil has a sun protection factor (SPF) of 7-8, and even that breaks down when the oil is heated, making it an unreliable form of sunscreen. But they were on the right path. The Ancient Egyptians tried extracts from rice, jasmine and lupine plants, which were mostly ineffective as a sunscreen but proved largely beneficial in improving the health of their skin. Zinc oxide—a popular sunscreen ingredient today—was first used for its medicinal purposes centuries ago. But, despite all these amazing breakthroughs from the past, the sunscreen we're most familiar with was first developed back in the '40s.

One of the first sunscreens in the U.S. was developed for the military because of overexposure to the sun in the Pacific Theater during World War II. Benjamin Green, a Florida airman and pharmacist, patented a sunscreen that would later be bought and brought to market in the early '50s as Coppertone and Bain de Soliel.

The facts about skin cancer

Let's first take a look at your skin. It's your largest organ—about 20 square feet—and the heaviest organ. It's there to protect your innards from the outside world, but it also has a role in maintaining your internal temperature and allows you to sense what's going on outside your body via more than 1,000 nerve endings.

Skin cancer occurs when there is an out-of-control growth of abnormal skin cells on the outermost layer of the skin—the epidermis. Mutations lead to abnormal cells, and these cells rapidly grow and form larger tumors, and spread to other parts of the body. More than 3 million Americans are diagnosed with skin cancer every year.

There are four main types of skin cancer: basal cell carcinoma (BSC), squamous cell carcinoma (SCC), melanoma and Merkel cell carcinoma (MCC). Melanoma is often described as the most serious skin cancer because of its ability to spread quickly.

The two main causes of skin cancer are the environment we live in and ultraviolet (UV) tanning beds. If caught early, skin cancer can be treated with little or no scarring and eliminated in its entirety.

Besides reducing your risk of skin cancer, sunscreen can also help with other issues, such as photosensitivity and various skin conditions.

Using sunscreen decreases the risk of developing skin cancer and skin precancers. With the regular use of SPF 15 sunscreen, you decrease your risk of developing squamous cell carcinoma by 40 percent, and melanoma by 50 percent.

Everyone over the age of six months should use sunscreen every day. Babies under six months are exempt because of their highly sensitive skin; instead, their delicate skin should be protected using shade structures and sun-protective clothing.

Every day, you should check online to see what the UV level is going to be in your area. A good resource is the UV index compiled by the U.S. Environmental Protection Agency (EPA), and there's also an app you can download for your smartphone.

A UV level up to a 5 is considered low to moderate, but a 6 or 7 is considered high, and an 8 to 10 is extremely high. Of course, your skin type is a factor here, but at higher UV levels, your skin can be damaged within 5 to 10 minutes.

UV levels are highest during the summer months; when the sun is at its highest during the day; when you're at a high altitude—such as when you're at the top of a mountain; and where the ozone layer is thin. Finally, clouds do block some UV light, but not all, and if the clouds are thin, the UV light could even be enhanced—don't feel a false sense of security just because it's a cloudy day.

Choosing the right sunscreen

There are many kinds of sunscreens available, whether tinted, scented, spray-on or liquid. The best sunscreen is the one you will consistently use.

Sunscreens work by helping to prevent the sun's UV radiation from reaching your skin. This happens with the use of two types of active ingredients—physical/mineral ingredients and chemical ingredients. Physical ingredients include minerals like titanium dioxide and zinc oxide, which block and scatter the rays before they can penetrate the skin. Chemical ingredients—such as avobenzone and octisalate—work by absorbing UV rays before they can damage your skin.

With the regular use of SPF 15 sunscreen, you decrease your risk of developing squamous cell carcinoma by 40 percent, and melanoma by 50 percent.

The level of SPF you should be using in your sunscreen may seem a little confusing at first. What you need to know is that sunscreen with SPF 15 and above is sufficient if you're mostly indoors. If you spend most of your time outdoors, you need SPF 30 or higher, preferably one that is water-resistant. Regardless of SPF, sunscreen should be applied every two hours, and immediately after swimming and excessive sweating.

Your sunscreen should also have broad-spectrum protection, which means the sunscreen protects against both UVA rays, which cause tanning and premature aging, and UVB rays, which cause sunburn.

The use of sunscreen is extremely important. Besides reducing your risk of skin cancer, sunscreen can also help with other issues, such as photosensitivity and various skin conditions. Many aestheticians will tell you that sunscreen not only keeps your complexion even and protects against visible signs of premature aging, but also shields essential proteins—like keratin—to keep your skin healthy and smooth.

Sunscreen alone will not provide complete protection against the sun—it is always safer to stay out of direct sunlight whenever possible, especially if the UV levels are 6 or above. You should also consider wearing sun-protection gear. And, yes, that means sunglasses, shoes that cover your feet entirely and a wide-brimmed hat. But there's also a huge selection of stylish clothing available created from fabrics that have an ultraviolet protection factor (UPF) of 30 or higher.