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Disturbing Facts About Sunscreen

Disturbing Facts About Sunscreen

What you should know about sun cream ingredients.

Sunscreen, summer, Sun, UV light, physical UV filters, chemical filters, sun cream ingredients, skin, SFP, inflammation, nanoparticles, free radicals, skin diseases

Summer is back again and so is the yearly dilemma: how can I enjoy the nice weather and protect my skin at the same time? With such a plethora of sunscreens which one should I use?

We can distinguish two types of UV filters. Sunscreen active ingredients can be classified as either physical UV filters or chemical filters. The former creates a barrier that scatters the rays and the latter absorbs the UV light. Doctors and scientists have always been debating on which of the two is the safest for both humans and the environment: in fact, each system has its advantages and side effects. Let’s see in details what they are.

While physical blockers are generally inorganic compounds, like titanium dioxide and zinc oxide, chemical blockers are organic molecules with long and weird names like avobenzone or octinoxate. Nevertheless, chemical blockers have frequently been accused to penetrate the skin and interfere with the hormone system causing serious diseases, like cancer. Also, physical filters cause less adverse reactions, like blisters, itching, rash, irritations, and they generally have a higher sun protection factor, the famous SFP. But, they will make you look paler when you apply them on your body.

This last problem can be solved by using nanoparticles as physical filters: the final product will be less opaque and the effectiveness increased. Problem solved, right? We should use physical UV blockers, shouldn’t we?

Apparently not; physical filters can increase the skin absorption of pesticides, causing adverse effects. In addition, nanoparticles are, just like the chemical filters, more reactive and they can generate free radicals.

Last remark, some scientists have hypothesized that sunscreen may actually promote skin diseases by inhibiting the skin inflammation. Normally mechanisms would alert us to stop sunbathing. Sunscreen obstructs this mechanism and makes us prolong our sun (and UV) exposure.

The choice is now up to you: which protection will you use? Chemical filters, physical filters, or maybe no holiday by the seaside?


Brand RM, Pike J, Wilson RM, & Charron AR (2003). Sunscreens containing physical UV blockers can increase transdermal absorption of pesticides. Toxicology and industrial health, 19 (1), 9-16 PMID: 15462532

Schlumpf M, Schmid P, Durrer S, Conscience M, Maerkel K, Henseler M, Gruetter M, Herzog I, Reolon S, Ceccatelli R, Faass O, Stutz E, Jarry H, Wuttke W, & Lichtensteiger W (2004). Endocrine activity and developmental toxicity of cosmetic UV filters–an update. Toxicology, 205 (1-2), 113-22 PMID: 15458796

Serpone, N., Dondi, D., & Albini, A. (2007). Inorganic and organic UV filters: Their role and efficacy in sunscreens and suncare products Inorganica Chimica Acta, 360 (3), 794-802 DOI: 10.1016/j.ica.2005.12.057

sunscreen, summer, Sun, UV light, physical UV filters, chemical filters, sun cream ingredients, skin, SFP, inflammation, nanoparticles, free radicals, skin diseases

This post was written by Chiara Civardi:
“Thanks for reading my article. I would love to hear what you think about it. Please comment or rate with the stars below.”


Chiara Civardi

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  • bubba
    June 17, 2014, 15:21

    “Hypnotized”? Uh. . .don’t you mean “hypothesized”?

    • Flora Brils@bubba
      June 19, 2014, 14:18

      Thank you Bubba for letting us know, we changed it!

  • ZERK
    June 18, 2014, 01:42


  • bob
    July 3, 2014, 05:54

    This is the stupidest thing I’ve read recently. First of all its SPF not SFP. Second of all, skin absorption of pesticides?! Ugh. Maybe if we’re hanging out in Monsanto cornfields all day, otherwise NO. This entire article uses pseudoscience and over exaggerated scare tactics for no reason at all. The author COMPLETELY oversimplifies and distorts very the complex biology of the human skin, immune system, and interaction with the sun and chemicals. From one scientist to another: dear author, please refrain from writing extremely dumbed down and pathetic articles such as these.

    • Chiara Civardi@bob
      October 16, 2014, 14:41

      The aim of this article was to be provocative and stimulate a
      reflection: we cannot simply take a pill (or a sun cream, in this case) and
      think we’re safe and sound from everything. We should pay attention when sunbathing:
      suncare products will not remove the risks if we expose ourselves the whole day.
      From these negative comments I understood I did not succeed in my aim, so I
      could have written the article better. Thus, I think it would be useful to
      clarify here a few points.

      1. Errata corrige: SPF (as well as hypothesised). I’m
      sorry, it was a typo. My bad. Plus, sometimes the Word automatic corrector is
      not really doing its job.

      2. Of course I simplified the subject: otherwise I
      wouldn’t have needed much more text (and time). I wanted to give a glimpse on
      some insidious aspects.

      3. The elements I proposed are anyway
      documented by scientific publications. In particular:

      a. The issues of organic filters have been debated
      for years (in particular, their estrogenic activity and their lipophilic
      nature) and, just to give an example, Krause et al. (2012) evidenced how some
      of these filters caused a proliferation of breast cancer cells. In vitro. I
      know that in vitro results may completely differ from in vivo ones, but this is
      well known. We do not invalidate such results just because they are in vitro,
      otherwise we would be lost.

      b. I report the results of Brand et al. (2003)
      where they state “The dermal penetration of the herbicide 2,4-D can be enhanced
      by commercial formulations containing chemical ultraviolet (UV) absorbers, the
      absorbers themselves and the insect repellent DEET. This work has been extended
      to determine whether commercially available sunscreens containing the physical
      UV absorbers titanium dioxide (TiO2) or zinc oxide (ZnO) enhance the
      transdermal absorption of pesticides.” That’s true, we don’t live in a
      cornfield, so we probably won’t experience acute effects, nonetheless we may
      experience chronic issues. In addition, I would like to draw the attention to
      the research conducted by Schmid et al. (2011), where he detected high amounts
      of DDT (from Africa, if I’m not wrong) in Swiss lakes: chemicals (and
      pollutants or whatever) can move, even far away from their original places.

      Final remark, as I said, I am really sorry that
      my take home message was not as clear as I expected or as it seemed to me. The
      feedbacks provided made me realise that. I hope that this note will work as a
      clarification of my “dumb and pathetic article”.

  • node
    July 12, 2014, 10:56

    I agree with the commentor below. There is some serious scare tactics going on here. Sunscreen has been accused of causing cancer?? Either you have some scientific reference for this claim (not given in the blog) or else you are spreading dangerous, misinformed ideas. You are promoting this “accusation” to the level of science by suggesting we take it as a reason to not use sunscreen.