Purchasing a bottle of sunscreen can be a baffling experience. Do waterproof sunscreens really stay on after you swim? Does a sunblock shield you better than a sunscreen? And which products protect you best from skin cancer? Starting next summer, thanks to new regulations recently passed by the FDA, sunscreens will have to pass tests to support their claims and labels will be easier to read.

Applauded by the American Academy of Dermatology, but considered too weak by other groups, the new rules are designed to prevent false claims and help consumers select the best product for their needs.


To understand the new rules, it helps to understand how sunscreens work.

Sunscreen 101

Suncreens fall into two categories, chemical and physical — a reference to how the sunscreens work, not their active ingredients. Chemical sunscreens interact with the skin’s top layer to absorb and convert ultraviolet (UV) rays before they harm the skin. This process takes some time to become effective, which is why the instructions say to apply a half hour before sun exposure. Examples of chemical sunscreens are oxybenzone and avobenzone.

Physical sunscreens, which include zinc oxide and titanium dioxide, sit on the skin’s surface and reflect UV rays. Though they start working immediately, these mineral sunscreens typically leave a whitish cast on the skin. Manufacturers often micronize the particles to make them less visible. When particles are micronized to less than 100 nm (nanometers), they’re considered nanoparticles.

Many products on the market blend both chemical and physical sunscreens to offer the most complete protection. The goal, after all, is to shield ourselves from the two types of UV rays that affect our skin: UVA and UVB.

UVB rays have traditionally gotten all the attention because they’re responsible for frying you to a rosy crisp. Though UVBs only penetrate the outer layers of the skin, they’re a major contributor to skin cancer. At Lake Tahoe, we’re particularly vulnerable to UVB rays, which are 18 percent stronger than at sea level and increase three percent for every 1,000 feet you climb in elevation.

UVA rays penetrate deeper into the skin, cause damage to DNA, and are responsible for wrinkles and aging skin. They also contribute to skin cancer.

The SPF, or Sun Protection Factor, is a measure of how long a product protects you, but it only applies to UVB rays. If you’d normally burn in 20 minutes, an SPF 15 should protect you for 15 times longer, or five hours. Of course, this is under perfect conditions — no sweating, no swimming, and no toweling off. Even then, five hours is a long time, which is why manufacturers tell you to reapply often.

The shortcoming of the SPF system is that is has nothing at all to do with UVA rays. Though some products currently claim ‘broad spectrum’ protection, meaning they’ll shield you from UVA as well as UVB, it won’t be until next summer that you can be sure the product was tested for compliance.

The new rules

Starting next June, here are the changes you’ll find:

• The term ‘sunblock’ will no longer be permitted.

• The term ‘broad spectrum’ may only appear on sunscreens that have shown they protect against both UVA and UVB. The SPF number, however, will still only apply to UVB. If you want to know exactly how much protection you’re getting from UVA, you’re out of luck. The FDA requires only that UVA protection increase proportionally as SPF rises. An SPF 45, therefore, will offer more UVA protection than an SPF 15, but you’ll have no idea how much actual UVA protection that means.

• Sunscreens with SPF 15 or higher may claim they protect against skin cancer. Broad spectrum products will, in addition, be able to claim they protect against sun-related skin aging. No products will be able to claim they prevent either skin cancer or skin aging.

• All labels will carry a fact box, similar to that seen on over-the-counter drugs, listing warnings and other information. For example, sunscreens with an SPF below 15 will warn that they do not protect against skin cancer.

• Because all sunscreens eventually wash off, the terms ‘waterproof’ and ‘sweatproof’ will be banned. A product may claim it is ‘water resistant’ if testing shows that it maintains its SPF for either 40 minutes or 80 minutes after a person sweats or goes swimming. If a product is not water resistant, the fact box must warn you of such.

• No sunscreen may claim it lasts more than two hours unless proof is submitted to the FDA.

• The new rules are slated to cap SPF values at 50. Though the FDA is seeking further comments on the matter, it says there’s no convincing data that SPFs over 50 are meaningful. Here’s why: As SPF goes up, UV blockage does not go up proportionally. SPF 15, for example, blocks 93 percent of UVB rays. Double the SPF to 30, and you’d expect UVB blockage to double too, but it only increases to 97 percent. Jump to SPF 50, and the product blocks only one percent more UVB than SPF 30.

Are the new rules too weak?

The Environmental Working Group, a consumer watchdog group based in Washington, D.C., believes the FDA’s rules don’t go far enough to protect Americans. Out of 530 sunscreens with SPF 30+ analyzed by the group this year, 330 offered so little UVA protection they could not be sold in Europe, where standards are stricter.

Because the FDA’s test for UVA is ‘pass/fail’ with a fairly low threshold, products that just barely pass get the same thumbs-up as those that offer much higher UVA protection, making it hard for consumers to choose the best product.
And although the safety of oxybenzone and other ingredients has come under question, the FDA continues to allow these chemicals in sunscreen. Oxybenzone is absorbed into the skin, where it easily turns to free radicals when exposed to sunlight. Free radicals, in turn, can lead to skin aging and cancer. Oxybenzone is also a suspected hormone disruptor.

Meanwhile, the FDA is dragging its feet to approve safer alternatives commonly used in Europe. Three of these alternatives — Tinsorb M, Tinsorb S, and Mexoryl SX — are between three and five times more protective than avobenzone, the most common UVA filter used in the U.S. Furthermore, these chemicals penetrate less in the skin and have no hormone-disrupting properties. Be aware that certain herbs and medications, including St. John’s Wort, ibuprofen (Advil), and many antibiotics make you more photosensitive.

If you’re concerned about the toxicity of ingredients, visit the Environmental Working Group’s website ( for its list of the safest sunscreens.

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