Is my sunblock poisonous?!

Ever since I was little, my mom always made sure that I put on sunblock before going outdoors. She correctly believed that the purpose of sunblock was to prevent skin cancer, which according to the American Cancer Society is actually “the most common of all cancers, accounting for nearly half of all cancers in the United States”.  (2013). Now, as a habit, I wear sunblock every day before going outdoors for cross-country practice. My teammates make fun of me for being “paranoid”, but I think that taking precautions is important; I do not want skin cancer! I always argue about the importance of sunscreen. Thus, you can imagine the shock when I read an article called “Your sunscreen might be poisoning you” by Dr. Perry, an Adjunct Associate Professor at Columbia University on the Dr. Oz  TV show website. I was a bit hesitant about the reliability of claims from the Dr. Oz show, (an American TV talk show hosted by Dr. Oz, a teaching professor at Columbia University) since I assume from experience that TV shows are often more for entertainment and may misrepresent the truth. As a result, to clarify whether I have been poisoning myself for sixteen years, I decided to research the chemistry of sunblock: what are some common ingredients? How do they work? And most importantly, do they really harm us?

According to the University of California San Francisco School of Medicine,  there are two types of active ingredients in sun blocks: physical, which “reflect or scatter UV radiation before it reaches your skin” and chemical, which “work by absorbing the energy of UV radiation before it affects your skin.” (2013).

According to Dr. Elizabeth Hale of the Skin Cancer Foundation, the most common physical sunblock used is either zinc oxide or titanium oxide. (n.d.) In a sense, applying them is almost the equivalent of applying white paint, as they literally “block” the sunrays. (Hale, E. n.d.) For example, as seen in the image, zinc oxide is literally a white powder.

Image 1: Zinc Oxide

These physical sunblock ingredients absorb both UVA and UVB rays, which is known as “broad spectrum” (a term you should look for on your sunscreen labeling!) and are large enough particles that they do not enter into your bloodstream. (Hale E., n.d.)Thus, they are both harmless and effective. The drawback, however, is that they are not so visually pleasing unless you want to have a white layer on your face. I researched my own Avene sunblock and found it to be a physical sunblock; it is indeed very white are hard to spread apart—something I found annoying at first, but now I’m glad that at least I’m being effectively protected from the sun.

The consumers’ natural preference of a sunblock that wasn’t so “whitely” visible like a layer of paint on their faces therefore led to the development of chemical sunblock—and this is where the problem begins. One common chemical ingredient is called oxybenzone, which is a chemical that absorbs UV rays. It is so common, that according to a CNN article, “56% of beach and sport sunscreens contain the chemical oxybenzone.” (Dellorto D., 2012).

Image 2: Oxybenzone

Dr. Perry’s article on the possible poisonous effects of sunblock was referring to oxybenzone; he claimed that as an endocrine disruptor (an external compound that disrupts the physiological actions of our body’s natural hormones)(Aguirre C., n.d.), it “can cause abnormal development of fetuses and growing children… early puberty… low sperm counts and infertility… the development of breast and ovarian cancers…prostrate cancer…”. (Perry A., 2013) After reading this, I immediately looked for other sources’ claims on oxybenzone to confirm Dr. Perry’s claim. First, the CNN article referenced before reported that “The American Academy of Dermatology maintains that oxybenzone is safe.” (Dellorto D., 2012) After this, I thought, “Okay, so the government thinks that oxybenzone is safe. Then is this the Environmental Working Group and Dr. Perry crazy?”This is when I came upon an article by Dr. Claudia Aguirre of the International Dermal Institute,  which shed light on the studies causing people to blacklist oxybenzone. One study showed that the harmful effects of oxybenzone were done on rats that were ingesting oxybenzone in toxic amounts. Another study was on whether the chemical would penetrate deep into the dermis in the first place, and although the answer was yes, the study was done on skin samples in a lab—not on human beings. Finally, another study on oxybenzone “saw deleterious effects on humans”, but “the participants were asked to use about 6 times the recommended amount of sunscreen needed to prevent sunburn”. (Aguirre C., n.d.). Thus, in the end, Dr. Perry’s claim is true—but only if you use a crazy amount of sunscreen with oxybenzone.

After doing this research, I learned a lot about sunscreen, and I think it was interesting to research the chemical ingredients in our everyday products. I had always assumed that sunscreen was just some “magical” skin cancer preventer! Also, an important implication from this research is that we should never immediately trust claims made by articles online, even if the author, like Dr. Perry, is an adjunct professor at Columbia University. We should look more in depth into the studies that the claims are based on, and decide whether we want to use these products. Dr. Perry was too extreme in his claim, which confirms my initial assumption that people on TV shows tend to exaggerate and cannot always be trusted. Thus, we have to be careful to what extent we should believe in others’ claims, and of course, we should continue to use sunblock (use the recommended amount of the equivalent of a shotglass, or two tablespoons, to the face and body) (Hale, E., n.d.)!


Aguirre C. (n.d.). Shedding Light on Sun Safety – Part Two Retrieved from

American Cancer Society. (2013, March 25). Skin Cancer Facts. Retrieved from

Dellorto D. (2012, May 16). Avoid sunscreens with potentially harmful ingredients, group warns. Retrieved from

Hale, E. (n.d.) Ask the Expert: How much sunscreen should I be using on my face and body? Retrieved from

Perry, A. (2013, May 7). Your Sunscreen Might be Poisoning You. Retrieved from

University of California San Francisco School of Medicine. (2011, June 10). Sunblock. Retrieved from


Wikipedia Commons. n.d. Zinc Oxide. Graphic. Retrieved from

The Medical Dictionary. n.d. Oxybenzone. Graphic. Retrieved from

Leave a Reply

Your email address will not be published. Required fields are marked *