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Debunking Myths : Hyaluronic Acid and Sunscreens

Hello readers. If you've been following the blog, you have likely noticed that I've taken a bit of a hiatus for the past few months. Thanks for bearing with me as I've started a new job and haven't felt motivated to write with the status of current events.

Today, I want to share with you some information I recently read about hyaluronic acid and sunscreen, two topics I covered in earlier posts. Through Instagram, I found the accounts of Jessica DeFino (@jessicadefino_) and Michelle Wong (@labmuffinbeautyscience). Both do a great job debunking beauty myths as a journalist and scientist respectively.

Hyaluronic Acid

The article by Jessica DeFino on hyaluronic acid that I wanted to share was initially published on the Harper's Bazaar website back in March. Unfortunately, it has since been taken down.

One of the most interesting takeaways from her research was that no original study was available for citation to substantiate the statistic that synthetic hyaluronic acid can hold 1000x its weight in water. This is concerning because this claim is used throughout the industry in marketing materials. I even cited it as a common claim in my post on the ingredient.

Since I can't link to her article, I want to share a link to this blog post where one of her sources, scientist Wendy Ouriel, tested hyaluronic acid in a laboratory setting. She could only create a gel when adding 10-50x the weight of the hyaluronic acid in water, far from 1000x. This is an interesting experiment, but her more important conclusions are two-fold: First, skin care companies are passing along this unsubstantiated claim as factual without doing their own research, which is concerning and misleading to consumers. Second, in her experience as a formulator, hyaluronic does not seem to be such miraculous skin hydrator after all. It may not be readily absorbed into the skin, meaning its moisture absorbing effect may actually draw moisture out of the skin as it sits on the surface.

Based on my time in the industry, I'm also curious about suppliers of hyaluronic acid. In general, scientists at skincare companies will consult technical data sheets and research from ingredient suppliers. Without knowing where the claim originated, it's hard to say if it was based on supplier data or a tenuous connection to research on naturally occurring hyaluronic acid. Either way, this shows that trusting others to substantiate claims is ill-advised.

So what does this mean for you as a beauty consumer? You can ignore the "1000x its weight in water" claim for any hyaluronic acid product. But does that mean you should avoid the ingredient altogether? Not necessarily. If you're using a product that contains hyaluronic acid and you are having positive results, it may be used in a small enough concentration that you're enjoying the benefits of the other ingredients in the formula. But if you've been trying hyaluronic acid products and noticed your skin is drier or more irritated, this may be an aha moment! The product may be having the exact opposite of its intended effect and drawing moisture out of your skin. If you're having a bad experience, it's time to move on.


My additional research on sunscreen was initiated by an Instagram post by the account @labmuffinbeautyscience. It read:

MYTH Mineral sunscreens work by reflecting and scattering UV.
TRUTH they mostly work by absorbing UV and converting it to heat - just like other sunscreen ingredients.

I was surprised to read this because that mechanism is so commonly cited. I mentioned it in my sunscreen blog post by referencing white-nosed lifeguards. However, while a white cast will reflect the visible light spectrum, the reflection of UV light is minimal. You can read more in this paper by Cole et al. "Metal oxide sunscreens protect skin by absorption, not by reflection or scattering" but the title gives away the conclusion. For zinc oxide and titanium dioxide, only about 4-5% of the UV protection comes from the reflection action, the rest is from absorption.

I spent many years of my career working on sunscreen so I initially felt embarrassed to be misinformed, until I read the caption which mentioned that this error is commonly found in articles and peer-reviewed dermatology papers. Sunscreen active ingredients are commonly divided into the two categories of "physical" and "chemical", with physical including zinc oxide and titanium dioxide and chemical including avobenzone, oxybenzone, homosalate, and octisalate. The data presented in the paper above shows that this separation is not valid, and a better way to differentiate is mineral and organic. (To be clear, this is organic in a chemistry sense as the compounds contain carbon, not in a farming sense.)

My Commitment for the Future

The beauty of science is that there is always new research and information. In the past, I've written this blog based on my personal experience in the industry. I've now found that this makes the information I'm presenting susceptible to myths that exist in the industry. To avoid perpetuating misinformation, in the future I commit to digging deeper and doing additional research into scientific studies to verify the information I'm sharing. To that end, I'll start linking sources at the bottom of my posts. Thank you for joining me on this journey!

If you want to follow the two women I mentioned above, you can follow their Instagram accounts and go to their websites to support their work:

Finally, if you are looking to make a difference in the current climate of anti-racism activism, one step you can take is supporting Black-owned beauty brands. There are many lists being published right now if you want to do some research. I found this article from Essence to be unique in that it focused on the founders and not just the products: Meet the Founders Behind 75 Black-Owned Skin Care and Cosmetic Brands You Should Be Shopping.

Have you had a great experience with a Black-owned beauty brand that you would like to see me highlight in a future brand spotlight post? Have you found other myth-busting beauty writers or scientists that are doing great work? Were you surprised at these myths about hyaluronic acid and mineral sunscreens? Let me know in the comments below!

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