Suspected Carcinogens in Some Sunscreens

By Gabe Mirkin, M.D.

In May 2021, an independent testing lab, Valisure, found elevated levels of benzene, a suspected carcinogen, in some sunscreens. As a result, Johnson & Johnson recalled five kinds of Neutrogena and Aveeno sunscreen sprays, and CVS stopped selling some of its sunscreen products (Dermatology Times, May 25, 2021).

In August 2021, Haereticus Environmental Laboratory, a nonprofit organization, asked the U.S. Food and Drug Administration (FDA) to withdraw sunscreens that contain the ingredient octocrylene, found in almost 2400 skin products (Chemical Research in Toxicology, March 2021).

Two years ago, in March 2019, the FDA proposed new rules on sunscreen safety:
• Only two of the active ingredients in sunscreens, zinc oxide and titanium dioxide, are “Generally Recognized As Safe (GRAS)”
• Two sunscreen ingredients, PABA and trolamine salicylate, are no longer generally recognized as safe
• The other twelve active ingredients currently in use may not be safe
• Sunscreens that include insect repellents are not considered safe
The FDA is supposed to release the final rules no later than September 27, 2021; I will report on them as soon as they are issued.

We do not know how safe sunscreens are because they have never been tested systematically. Oxybenzone in sunscreens has been shown to be absorbed into the bloodstream in humans and to disrupt hormones in animals. Many sunscreens contain the filters octylmethoxycinnamate, benzophenone-3 or octocrylene, which reflect ultra violet rays away from your skin to protect it only when they are on the surface of the skin. However, when these sunscreens are absorbed and the skin is not re-coated, they increase skin production of harmful oxidants that can cause skin aging and cancer (Free Radical Biology and Medicine, September 2009).

Different Types of Sunscreens

Sunscreens help to prevent sunburns and skin cancers because they actually block the ultraviolet rays of the sun that damage the skin. Sunscreens are classified as those that contain:
• Blockers: minerals that block some of the sun’s rays (zinc oxide and titanium)
• Absorbers: chemicals that absorb the sun’s rays so that less pass through to the skin (benzophenone, dioxybenzone, oxybenzone, sulisobenzone, sulisobenzone sodium, obenzotriazoles)
The chemical sun ray absorbers are more effective than the mineral blockers, and therefore they dominate most of the sunscreen market today. However, both types of sunscreens can be absorbed into the bloodstream (Toxicol Rep, May 27, 2017;4:245–259), and the chemical sun ray absorbers are absorbed more rapidly at more significant levels (JAMA, May 6, 2019). Some of the absorber sunscreens are “endocrine disrupters” that may increase cancer risk (Int J Androl, Jun 2012;35(3):424-36). We have known all of this for nearly 25 years (Lancet, 1997;350(9081):863-864).

Dermatologists who have been among the strongest supporters for the regular use of sunscreens to help prevent skin cancer are now very concerned about the harm that some of the ingredients may cause (J Am Acad Dermatol, 2019;80(1):266-271; Dermatol Clin, 2019;37(2):149-157). The FDA has already concluded that the risks for chemical absorbers such as para-aminobenzoic acid (PABA) and trolamine salicylate outweigh their benefits and has proposed classifying them as unsafe.

Protecting Your Skin from Sun Damage

Almost all skin cancers are caused by excessive exposure to sunlight and/or exposure to human papilloma wart viruses (HPV). Basal and squamous cell skin cancers are caused primarily by cumulative exposure to sunlight over a lifetime, so every time you expose any part of your skin to direct sunlight for more than 10 minutes, you may be adding to the damage that you have received from previous exposures. Melanomas are different. They can be caused by a single sunburn at any age.

The most effective protection from UV light is a roof, and then clothes. Sunscreens are the least protective, but they are better than nothing. I recommend using sunscreens that have titanium and/or zinc oxide as the only active ingredients, even though they may be less effective than the sun absorber sunscreens. They need to be applied thickly enough to leave a white coating on your skin, and reapplied when you can no longer see the white coating.

Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.