How Do Sunscreens Work?

Most people believe that products sporting a really high number have the most powerful sun protection, … SPF 60 sunscreen does NOT give you twice as much sun protection than an SPF 30. In fact, it only blocks an extra 1% of…

From toddlers to baby “oil” boomers, most Americans have finally embraced the concept that sunscreen is essential to life. South Floridians are among the front runners in the wellness revolution, avidly pursuing youth and radiance while fighting the menace of skin cancer, but there is more to applying sunscreen than just dedication and commitment.

As a dermatologist, I am frequently consulted for advice on sunscreen. Most people believe that products sporting a really high number have the most powerful sun protection, proof that marketing sometimes plays against medicine. Here is a spoonful of truth for your beach bag.

SPF 60 sunscreen does NOT give you twice as much sun protection than an SPF 30. In fact, it only blocks an extra 1% of UVB rays. How can that be true? Answer: The protection you get isn’t proportional to the SPF number.

This is what we need to know about SPF and UVB:

UVB is the sunburn ray. UVB is more intense near the equator, at high altitudes, during summer (when the earth is closer to the sun) and between the hours of 10 a.m. and 3 p.m. The longer one is exposed to the sun, the more likely skin will burn.

The SPF value indicates how well a product protects from UVB. Caution: it tells you nothing about cancer and wrinkle causing UVA protection (more on that later).

Looking at this chart might be a bit of a surprise.  

• SPF 2 means 50% of UVB rays are blocked
• SPF 4 means 75% of UVB rays are blocked
• SPF 10 means 90% of UVB rays are blocked
• SPF 15 means 93% of UVB rays are blocked
• SPF 30 means 97% of UVB rays are blocked
• SPF 50 means 98% of UVB rays are blocked
• SPF 70 means 98.5% of UVB rays are blocked
• SPF 100 means 99% of UVB rays are blocked

Notice that once we reach SPF 15 we have already blocked 93% of UVB rays. After that the percent of UVB blocked barely changes as the SPF numbers go up. The sweet spot is SPF 30-45 where 98% of the UVB rays are blocked, and most dermatologists agree. In fact the FDA recently passed a law that will cap the SPF number in 2013 to no more than SPF 50, in order to prevent unrealistic claims.

How do sunscreens work?

Two basic sunscreen ingredients:

Chemical sunscreens go into the skin and use a chemical reaction (molecules vibrate very rapidly to dissipate heat) to block UV rays from passing deeper into skin. This process reacts as heat, which is why some sunscreens may make users feel extra hot in the sun. The chemicals break down during this sun blocking chemical reaction, which is why sunscreen products indicate the necessity to reapply every couple of hours when continually exposed to the sun.

Mineral sunscreens sit on top of skin and reflect and scatter the sunlight rays off the skin without a chemical reaction and without creating the warmth. Mineral sunscreens include zinc oxide and titanium dioxide. While years ago, mineral sunscreens were white on the skin, today’s modern versions have been ‘micro sized’ making it difficult for the eye to see them on the skin. They don’t pass into skin and they don’t readily break down when they block the sun so their sun protection tends to last longer.

Both chemical and mineral sunscreens block UVB well and can provide the same SPF values.

Now let me discuss UVA.

UVA protection is also critically important for anti-aging and skin cancer prevention.

UVA is out all day and all year and the SPF of a product provides no information about UVA protection. A sunscreen product can claim to give UVA protection even if it doesn’t protect from all the bad UVA rays. Most chemical sunscreens offer some UVA protection, but don’t cover the entire spectrum of UVA light.

Sunscreen formulation is a complicated process. This is my advice to keep it simple. Look for a sunscreen product that has 5% or more zinc oxide in it because zinc oxide is the only ingredient that blocks all the way through the UVA wave spectrum to 400nm. Avobenzone is also a chemical blocker of UVA which has good coverage, but it also has stability problems and may not last in the bottle or on the skin.

Bottom Line: Find a sunscreen that has 7% or more micronized zinc oxide such as Elta MD or something brand new on the market that has my personal signature, “Ultra.”

One investigative visit to a sundries counter was enough to inspire to me to an imagination drawing board with a quest to create a real sunscreen, a product not packaged with gimmicks but destined to serve the public with genuine protection from the sun.

“Ultra” was designed to protect skin from the entire UVA and UVB spectrum. “Ultra” is non-greasy and has no odor. “Ultra” rubs in completely and does not leave a white residue behind. “Ultra” is not only non-comedogenic, but actually can improve acne prone skin. Once in the making, I wanted my personal product to be more than sunscreen and to be loaded with anti-oxidants to help fight wrinkles. I wanted a product that would even out discoloration and not only prevent, but actually improve age spots.

After 10 years of research and clinical trials, I am pleased and proud to release “Ultra,” an ultra violet protector and skin rejuvenating cream. This sleek Balshi MD Derma-Ceutical sunblock is broad spectrum protection, anti-aging, acne improving, wrinkle resolving, pigment correcting and SPF 40 day cream. It’s the first and only sunscreen of its kind (US Patent Pending). It is astoundingly “clean” as it protects, prevents, repairs, and rejuvenates!!! “Ultra” is the newest companion to the complete line of Balshi MD Derma-Ceuticals, created to be “the” ultimate resource for the healthiest and most strikingly beautiful skin in the world.