How to Best Apply Sunscreen to Protect Against Skin Cancer

Many know that ultraviolet rays (UV rays) from the sun can lead to sunburn, speed up skin aging, discolor the skin, cause inflammation, and increase our risk of skin cancer. Overexposure to UV rays from the sun can damage the DNA in our skin cells, which tells our cells how to function. Built-up cell damage over time can cause cells to grow out of control and can lead to skin cancer. Sunscreen protects our skin from harmful ultraviolet radiation. The chemicals in sunscreen contain organic compounds, such as titanium dioxide and zinc oxide, that have a chemical reaction when exposed to UV rays. This chemical reaction transforms UV rays, absorbing, scattering, and reflecting them away from the body.

But choosing sunscreen can be overwhelming because there are so many options available. Your first instinct may be to look for a recognizable brand; however, first look for the Sun Protection Factor (SPF) level of the sunscreen. SPF levels can range from SPF 15 to SPF 100. The stronger the SPF level, the more protection it can offer from UVB rays and short-wave ultraviolet light. UVA light can lead to skin damage, wrinkles, and premature aging. However, UVB light has been established to be responsible for skin cancer.

Broad-spectrum sunscreen protects skin from both UVA and UVB rays. When it comes to picking a sunscreen, the general rule is to choose SPF 30 or higher if you’ll be outdoors and exposed to direct sunlight. Use SPF 15 or higher even if you’re spending your days indoors, especially if you have windows that let in sunlight. Remember that the sun’s rays can bounce off surfaces such as walls and floors, exposing your skin to UV radiation.

Here’s how to apply sunscreen properly:

The 15-minute rule: If you’re headed outdoors, apply sunscreen at least 15 minutes before going out. Sunscreen is relatively thick, and it will take at least 15 minutes for your skin to absorb the lotion. If you go out before the sunscreen has fully absorbed and expose yourself to the sun, you won’t be protected. You may even begin to sweat before the sunscreen has the chance to be fully absorbed by the skin.

Rub thoroughly: An ample amount of sunscreen needs to be rubbed thoroughly into the skin to ensure absorption. Apply sunscreen to all areas that will be exposed to the sun. Pay special attention to spots that are most often forgotten, such as the ears, back of the neck, back of hands, tops of the feet, and the hairline. Also remember that the exposed skin on your head should be protected too.

Reapply: John Hopkins Medicine recommends that you reapply sunscreen every two hours, especially after swimming and sweating. You may wonder why you need to reapply sunscreen if the brand you bought is “water-resistant,” and a waterproof sunscreen shouldn’t wash off easily by swimming or sweating. According to the FDA, there’s no such thing as waterproof sunscreen. All sunscreens will ultimately wash off or lose their effectiveness. The 2-hour rule for reapplication exists because the compounds in all sunscreens will only remain effective for two hours, and the time gets shortened if your skin gets wet or if you sweat.

Experts even advise that you reapply sunscreen regardless of the weather or your activities as long as you are outdoors and exposed to the sun. Remember, UV rays, particularly UVA rays, can penetrate clouds.

Sunscreen is crucial in preventing skin cancers and skin precancers. To learn more about skin cancer screening, prevention, and treatment, contact Tampa Bay Radiation Oncology.

At Tampa Bay Radiation Oncology, more than a thousand men and women diagnosed with cancer each year turn to our trusted team of cancer specialists. We encourage you to call us, ask us a question, or consult with us to get a second opinion so you, too, can experience the difference.