Friday, July 24, 2015

Retinyl Palmitate (Just When I Thought.....Part 2)

In this post I wanted to address the claim from the Environmental Working Group's (EWG's) sunscreen guide that retinyl palmitate is a toxic ingredient.

What is retinyl palmitate?
Retinyl palmitate is an ester, consisting of vitamin A and palmitic acid. It is included skin care preparations as an antioxidant and cell regulator. It is also approved by the FDA for use as an additive in food, as well as a supplement. For our purposes we'll be focusing only on its use in sunscreen.

Claim: Vitamin A in sunscreen causes skin damage and is can cause skin cancer.

This is good time to introduce a term called "cherry picking".
"Cherry picking has a few different definitions, but it is most often thought of as the process of selecting a small amount of information or data to attempt to prove a point, while ignoring contradicting information. When cherry picking information, a person may end up with a faulty theory or position on a topic because all relevant information was not considered. A person might choose information in this way either on purpose or inadvertently, such as when a person might inadvertently only look at data that is easy to find, presenting a false impression. The term is more commonly used with someone who purposefully ignores contradicting information, however."
The first claim is that retinyl palmitate is carcinogenic. The implication is that the FDA funded National Toxicology Program (NTP) study from 2000 showed this to be true. Here are the problems:
  • study was done on mice, with retinyl palmitate isolated, not in a cosmetic preparation or sunscreen
  • the hairless mice used have a thin epidermis, which allows for more UV penetration, and have a propensity to develop more cancerous tumors
  • the study actually failed to show a link with statistical significance, and even if it had, you then have to assume the findings are 100% comparable to a human reaction

The second claim is that retinyl palmitate causes free radical activity and damage to skin cells. There have been studies linking retinyl palmitate to free radical damage in the skin (1, 2) but it's important to note three points.

  • The studies were again done isolating retinyl palmitate's reaction to UV, not in a skincare or sunscreen formula. 
  • This does not take into account the natural antioxidants in the the skin that counteract free radical activity, not to mention the antioxidants that would be within a well formulated sunscreen
  • Our bodies encounter (and make!) free radicals all the time. It's a complex stew of interactions and vitamin A acts like an antioxidant within this structure. Touting results that were created in a vacuum just doesn't make sense, the skin doesn't work that way.

I believe the concerns about retinyl palmitate are not supported by the science. But, if you only read the cherry-picked elements out of the studies that the EWG presents, I see how it could be alarming at first. Bottom line? Retinyl palmitate was, is and will continue to be a valuable ingredient in our arsenal of chemicals used in skin care formulations. I've linked to all the complete studies above and listed some additional sources below if you want to dig in. Next up is Oxybenzone!

Links to more info/sources:

Tuesday, July 14, 2015

Just When I Thought I Was Done Talking About Sunscreen (Part 1)

Whew! I took a month off of writing posts after a whirlwind of a May. I had a tidy pile of ideas and topics for The Dermis when BAM! The Environmental Working Group (EWG) published their 2015 sunscreen guide. Somehow I had blocked out that this guide comes out annually, as well as the misinformation and fear and that goes with it. After a slew of well-meaning, rational folks began posting and reposting on Facebook and Twitter–to be honest–I had a moment.

Ok, it was more like a tirade. Fortunately, this only occurred within earshot of my partner and my dog (sorry guys). I have taken some slow, deep breaths and have realized this is the perfect time to talk about the EWG, what is being suggested by the guide, and what I think about it. I'll be breaking this into 3 separate entires. So just when you thought you free from my sunscreen posts.......

I learned a new term last week: internet crank

From Geraint Lewis and Michael J. I. Brown of
"....examples of the tactics used by online cranks, such as emotional escalation, errors of omission, dismissing experts and proclaiming to support science while simultaneously undermining it."
While not being used to refer to the EWG, I thought it expressed perfectly what I felt was going on when I read the report. So before I get to refuting some more specific points, it's important to discuss where I think the root of the problem comes from. The EWG's report is based on an arbitrary system and scale that they have created themselves, with no generally accepted scientific standards. It is not peer reviewed.

"What they are doing is developing their own system for evaluating things," said Dr. Warwick L. Morison, professor of dermatology at Johns Hopkins and chairman of the Skin Cancer Foundation's photobiology committee, which tests sunscreens for safety and effectiveness. "Using this scale to say a sunscreen offers good protection or bad protection is junk science." 
Dr. Morison has no financial ties to sunscreen makers, and his work with the Skin Cancer Foundation is unpaid.
The methodology used to determine the rankings, as well as who all is involved is hazy and hard to pinpoint. Here's a great infographic outlining the differences between the methods of the Cosmetic Ingredient Review (CIR) and the EWG. According to their website, the CIR reviews and assesses the safety of ingredients used in cosmetics in an open, unbiased, and expert manner, and publish their findings in peer reviewed scientific literature. The CIR has often taken heat for being industry-funded organization and yet, in comparison, its process seems way more transparent to me.

Thanks to Of Faces and Fingers for the infographic. (If you want to read a great in depth post about safety and methodology in regards to parabens you can find it here.)

So while widely read and accepted, I don't find the EWG's website a consistent or credible source of information. Now you know why. Next up? What they're saying about Retinyl Palmitate.