The Sunscreen Project, Part 13.2 (further updated articles)

/ Sunday, March 31, 2013 /
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For those who are both new readers and as a review for my old readers, all of my posts of Part 13 of The Sunscreen Project are knowledge articles, meaning they give advice on what kinds of sunscreens to look for, what kinds of ingredients to watch out for, etc.

Thus, in this edition, I will talk about what kinds of ingredients to avoid and give evidence as to why one should. Also, I will give recommendations for what kinds of ingredients to look for and why.

As usual, the articles that I cite will be listed at the end of this post. I will not be reviewing any scientific articles and their conclusions; I will just give facts and advice. One who would like to see reviews of articles, primary research, and their results should go to the reference articles I list.

Note: If you are new to this site and are a beginner in learning about sunscreen and/or are not a particularly sciency-type person, I would suggest you to start with the first Part 13 post of the Sunscreen Project (you can find this under the "The Sunscreen Project" tab at the top of this page). Each addendum adds on to the previous articles. This section is geared to be slightly more sunscreen-aficionado geared (i.e. will be more specific and detail-based).

Without further ado, here are Chemicals to think about:

Contraindications w/ avobenzone and octinoxate:

  • A combination of octinoxate degrades avobenzone via a chemical mechanism involving alkenes and cinnamates
  • Some companies try to minimize this effect by adding in stabilizers such as octocrylene. However, octocrylene isn't completely effective
  • Bottom line, there's still research going on in this field. For now it's best to be safe by choosing products that don't contain octinoxate and avobenzone together.

Zinc oxide vs. Titanium Dioxide (ZnO vs TiO2):

  • The two most popular inorganic sunscreen active ingredients that are approved for use by the US FDA in the United States are zinc oxide and titanium oxide. 
  • Of these two ingredients, zinc oxide provides more comprehensive coverage of UVA and UVB rays, and is less photoreactive and toxic than TiO2.
  • Recommendation: choose products that contain ZnO over those with TiO2.

  • Oxybenzone is a US FDA approved product for protection against UVB rays. It was first approved in the 1970s.
  • Recent studies by the US Center for Disease Control (CDC) have found that in laboratory settings, oxybenzone has been linked to "allergies, hormone disruption, and cell damage." It's even been shown to be linked to low-birth weight in baby girls. Definitely not so cool.
  • Bottom line? The thing is that the studies on "allergies, hormone disruption, and cell damage" were done on murine (mouse models) and rat models. Inherently, mouse and rat skin is a lot more sensitive than human skin. Therefore, the results have to be taken with a grain of salt when applying them to human skin. However, it is probably safer to not use products with oxybenzone on babies.

Retinyl palmitate:
  • Retinyl palmitate is a form of Vitamin A that is found in many sunscreens. It is often recommended by dermatologists as an anti-aging factor.
  • In 2010, studies conducted by the Environmental Working Group proposed that this ingredient may increase the risk of skin cancer. However, this was done in murine models. Once again, since murine and human skin are different in many ways, conclusions must be applied with a grain of salt when looking at human skin.
  • A 2011 study published in the Journal of the American Academy of Dermatology disproved the EWG's results, suggesting that retinyl palmitate is actually safe.
  • Bottom line? If you are extra scared, don't get sunscreens with retinyl palmitate. However, products with it shouldn't be too bad.

Overall thoughts:

  • The thing is that a lot of these chemicals were tested in a lab and not actually on people. Also, a lot of these chemicals were tested in ways that were not taking into account their interactions with other ingredients that are in the sunscreens themselves. Think lack of accounting of synergistic effects of other ingredients.
  • Fear also plays a factor here: think about all of the hype we hear about on the news. Some stabbing, some shooting, some poisoning, some threat out in in "foreign waters", etc. Very little portrayed news shows all sides of the story - often times, it is just the sensational parts that are published. Don't get sucked in - research all parts of the story before making conclusions.
With these factors in mind, here are the sunscreens that I've previously reviewed that people who are worried about these factors may want to think about:

John Su - Futurederm: Toxicity of Inorganic vs Organic Sunscreen Ingredients
John Su - Futurederm: How does Octinoxiate Degrade Avobenzone?

Oxybenzone problems:

The Daily Green
The Environmental Working Group
US Health News

Retinyl palmitate:

The Daily Green
US Health News

Lent is over

/ /
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I gave up blogging on VitaminCGoodness, but I'm back!!!

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Anyway, so reviews, thoughts, and meaderings on skincare and beauty products resume =D


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