Ask Pablo: Does Sunscreen Cause More Skin Cancer Than It Prevents?


Image Source: Kelly Sue

Dear Pablo: I have heard that sunscreen actually causes more skin cancer than it prevents. Is there any truth to this?

It sounds unbelievable but there is actually some truth here. In 2009, the Environmental Working Group released a major study on sunscreen, in which they independently tested almost 2000 sunscreens. Only 1 in 10 sunscreens offer superior protection and healthier ingredients. There are two main concerns about sunscreen; the protection that they offer, and the chemicals that they contain. Does Your Sunscreen Have You Covered?
The sun produces a wide spectrum of light, including the three bands of ultra-violet light that we call UVA (400-315 nm), UVB (315-280 nm), and UVC (280-100 nm). UVB is the band of light that causes sunburns and the only category of UV that sunblock is regulated for by the US FDA. Unfortunately for us, UVB only represents 4% of the UV radiation entering the atmosphere and UVA is much more responsible for causing skin cancer, premature skin aging, and other skin damage. Since UVA protection is not regulated by the FDA, many claims of UVA protection are not credible. Either the UVA protection is insufficient, or the active ingredient degrades too rapidly when exposed to sunlight, leaving you with inadequate protection after some time.

An additional concern is actually too much coverage. UVB light is required by the skin to produce vitamin D. Vitamin D deficiency seems to be the new medical buzzword and 30-50% of the US population are said to be affected by it.

Carcinogens and Hormone Disruptors In Your Sunscreen?
Some sunscreens, like Coppertone ultraGuard Sunscreen Lotion (SPF 15) contain oxybenzone. Oxybenzone is used because it blocks UVA and UVB but it gets absorbed into the skin, acting as a photosensitizer. Because of this it is believed to be a likely photocarcinogen. As if that weren't enough, oxybenzone is also a hormone disruptor that has been found in the urine of 97% of Americans over the age of six (CDC). Fortunately there has been a decrease in the use of oxybenzone but it is still approved by the FDA for use in sunscreen.

An additional area of concern are nanoparticles. Nano-sized (<100 nm) particles of zinc and other materials are now being used in sunscreen. While there is no evidence of absorption through the skin there is a risk of absorption through the lungs when using spray-on sunscreen. As always, healthy skepticism and use of the precautionary principle are advised.

What Can You Do To Protect Your Family?
In order to protect yourself and your loved ones from the sun and the unintended consequences of using some sunscreens here are a few suggestions.

  • More is not better: Sunscreens rated with SPF 55-100+ block just 1-2% more sunburn rays than an SPF 30 rated sunscreen.
  • Check your sunscreen: Find your sunscreen here and dispose of it properly if it doesn't pass muster.
  • Sunscreen loses its effectiveness. Check the manufacturer's date stamp and replace it if it is expired.
  • When you buy sunscreen follow Environmental Working Group's list of recommended sunscreens.
  • Look for sunscreens with avobenzone, Mexoryl, titanium dioxide, and zinc for UVA coverage.
  • Avoidance is best. If you don't have to be out in the sun between 10am and 4pm, stay in the shade.
  • The best sunscreen is the kind you wear. Outdoor clothing manufacturers are producing SPF-rated clothing to keep you comfortable and sunburn free.

Pablo Päster is a weekly columnist for TreeHugger.com, an experienced greenhouse gas engineer and the Senior Environmental Program Manager at Hara Software. Send your questions to Pablo(at)TreeHugger.com or submit the via this form and connect to his RSS feed.
More Resource On Sunscreen:
Last Call For Sunscreen
Lycomato's Ingestible Sunscreen Based on Tomatoes So You Don't Turn Into One
Face Off: Our Sunblock & Sunscreen Picks

Tags: Cancer | Cosmetics | Toxins

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