What Does the SPF in Sunscreen Mean?


Florida Medical Clinic Orlando Health

What Does SPF Mean?

Spring is here, and so are blue skies, blooming flowers, and warmer temperatures. While the intense sun of summer is still a few months off, it’s still important to practice good skin health.

The skin care aisle at your local pharmacy can seem very daunting. Every bottle of sunscreen has a seemingly random combination of numbers and specializations. If you’ve ever wondered how to interpret these labels and learn what the SPF in sunscreen means, look no further.

The sun produces more than just the visible light we see on a daily basis. The sun also produces three types of ultraviolet rays which are invisible to our eyes: UVA, UVB, and UVC rays. UVC rays are absorbed by the ozone, which means that they do not reach the Earth. UVA and UVB rays can prematurely age and damage the skin and increase your risk of developing skin cancer.

UVA rays are the most prevalent type of UV radiation, but not as intense as UVB. They can penetrate What Does the SPF in Sunscreen Mean? - Florida Medical Clinic Orlando Healthcloud cover as well as glass, and their intensity is consistent throughout the daylight hours. These rays penetrate deeply into the skin and are typically associated with skin aging and wrinkling. UVA rays are also the predominant ray in tanning booths, as they are the main contributor towards skin tanning.

UVB rays are the primary factor in sunburn and reddening skin. These rays damage the superficial layers of the skin. Unlike UVA, UVB rays are not consistently intense. Their intensity varies depending on hour, location, and season. They also do not penetrate glass as much as UVA rays. However, UVB rays can still damage your skin at any time of year, especially from reflective surfaces or snow and ice.

SPF, which stands for ‘sun protection factor’, indicates the amount of protection a product has against harmful UV rays. This protection comes in the form of specific ingredients which prevent the sun’s radiation from reaching the skin. You may be surprised to learn that a higher SPF doesn’t always mean better protection for your skin. SPF 15 blocks 93% of harmful rays while SPF 30 blocks 97%.

Sunscreen vs. Sunblock: What’s the Difference?

The terms sunscreen and sunblock are often used interchangeably. While both of these products aim to prevent radiation damage to the skin, they work in slightly different ways.

Sunscreen uses chemicals to filter out and/or absorb the sun’s radiation, and appear like a thin film on the skin. Sunblock uses ingredients which physically block ultraviolet rays, and can be thick in texture. Sunblock is generally recommended for people who are very sensitive to UV rays.

Protecting Your Skin

Using sun protective creams are just one part – albeit a very important part – of a complete skin What Does the SPF in Sunscreen Mean? - Florida Medical Clinic Orlando Healthprotection plan. Use SPF 15 lotions and creams throughout the year to protect your skin. If you’re going out on the water or for a day at the park, choose a higher SPF to suit your needs.

  • Choose the right sunscreen! Use sunblock if you are Burn easily? Choose a higher SPF.
  • Many sunscreens only protect against UVB rays. Look for ‘Broad spectrum’ protection for comprehensive coverage.
  • If you’re an athlete or spending time in the water, choose a waterproof sunscreen.
  • Don’t forget your lips! Your lips can burn just as easily as the rest of you. Choose a lip balm with a SPF rating of at least 15 and reapply frequently throughout the day.
  • Be generous with your application. You should generally expect to use about 1oz of sunscreen to cover your entire body.
  • Reapply sunscreen throughout the day if you are going to be outdoors, exercising, or at the pool or beach. Even waterproof sunscreen can wear off over time, especially if you are very active.
  • 10am – 4pm are usually the times of day where the sun’s rays are strongest. As tempting as it may be to lay in the sun, you should seek shaded areas instead to protect your skin.
  • SPF rated clothing is a great option for people who burn easily or have a strong sensitivity to UV rays.

On Florida’s sunniest, brightest days, it’s can be easy to develop a sunburn when you’re out on the beach or the water having fun. Fortunately, it’s easy to treat a sunburn.

Even one bad sunburn can dramatically increase your chance of developing skin cancer later, so stay safe and do what you can to protect your skin!



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