Glycerin is a Badass Queen. Here’s Why According to Science!
Hi there, friends! I hope you are doing well 🙂
While we’re all patiently waiting for the launch of Malezia (thank you for your patience), I thought it would be a good idea to quickly come on here and answer a question I get asked about EVERY. SINGLE. DAY.
That is….
Is Glycerin Safe for Fungal Acne?
The answer is yes. And I will be explaining all the reasons you should be using it down below!
But first, how do we know it’s not a problem?
Because glycerin is not a fat source and Malassezia is a lipophilic fungus and fatty acid auxotroph. Auxotrophic meaning there is a mutation in one of its genes that prevents it from synthesizing compounds essential for its survival. In this case, those are fatty acids of certain chain lengths which is why it searches for them in the environment. Without them, it cannot live.
“Malassezia are fatty acid auxotrophs, having lost their fatty acid synthetase genes; thus, they require lipids for growth.” (1)
Explained more simply, it’s like a person who doesn’t know how to cook for themselves and relies on Mcdonald’s drive-thru to stay alive. If the zombie apocalypse were to hit tomorrow, you better believe that person is f*cked.
In this scenario, your sebum and fat-containing skincare products are Mcdonalds. Malezia is the apocalypse.
You might be thinking to yourself, “well if Malassezia requires exogenous fats to survive, and glycerin isn’t a fat source, then why does everyone think glycerin is a problem?”
Great question! The answer to that is because I’m an idiot.
Let me explain.
The Conspiracy Against Glycerin: Why Everyone Thinks It’s Growth Promoting.
Perhaps you’ve noticed that Sezia.co flags glycerin as a “high sensitivity” ingredient. That would be my fault.
For those that don’t know, Sezia was based on the original research shared on Simple Skincare Science several years ago. At the time, the only research I could find on glycerin was a single paper whose abstract stated it could promote the growth of malassezia.
I didn’t have access to the full study back then because it’s from China, but prematurely warned everyone on the fungal acne guide to avoid glycerin anyway. That unfortunately snowballed out of control, and now everyone thinks glycerin is the black plague. Sigh.
Fast forward to today, I have read that paper in its entirety thanks to one of our readers (Hailey) who translated it for me and sent it via email. Ironically enough, there was an error in the original translation and the paper actually states:
“Glycerol cannot promote the growth of Malassezia, therefore cannot be used as a susceptibility test… [whereas] the influence of lipids on antifungal activity of drugs must be fully considered.”
In other words, the researchers were examining whether pairing certain ingredients with antifungal drugs reduces their efficacy against malassezia. They found that using fats such as oils and polysorbates makes them less effective. However, the same did not apply to glycerin.
This of course makes sense considering several other sources have had similar findings. For example, Caprilli et al found glycerin does not influence the growth of pityrosporum orbicuIare in culture testing. (2)
Note: pityrosporum is the former name of malassezia.
Additionally, Harding et al found a high glycerol-containing scalp treatment improves dandruff even in the presence of problematic lipids. (3)
Similarly, in a research letter Benaim-Pinto wrote how he healed seborrheic dermatitis (SD) in 18 patients by cleansing with pure glycerin. (4)
Note: both studies above are relevant because malassezia has been implicated in the pathology of dandruff and SD.
Most recently, Dobler et al used two glycerin-containing emulsions as controls to vet ingredients that promote malassezia growth. (5)
And if that wasn’t enough evidence, our super awesome microbiologist and cosmetic chemist has verified glycerin is safe through her own independent testing! 🙂
Why Glycerin Is Amazing for Skin.
Still skeptical? Perhaps you’ve tried glycerin and are convinced it broke you out. If that’s the case, sorry for the breakouts :’(
However, maybe I can convince you to try it out in our urea moisturizer! 🙂 Why would you do such a thing? Because if tolerated glycerin is actually an amazing ingredient with a ton of skin benefits.
For example, did you know that glycerin was the only humectant that was able to restore stratum corneum hydration in AQP3-deficient mice? (6) This may be particularly important for those with dry skin considering AQP3 is a protein that helps facilitate barrier recovery and improve skin elasticity. (7) The other tested molecules that had minimal to no effect included erythritol, xylitol, propanediol, and even urea!
This may be surprising to some considering how much I rave about urea, but it’s not the first time I’ve seen a study with these results. For example, Bettinger et al found that only a moisturizer with 10% glycerin was able to improve skin hydration. The same emulsion made with 10% urea or 10% propylene glycol performed no better than a moisturizer without humectants. (8)
This isn’t to say urea sucks (it absolutely does not – how it’s formulated dictates its performance) but you get the most bang for your buck combining the two. In fact, several studies have demonstrated that urea and glycerin have a synergistic effect, and work better together than either used alone. (9, 10, 11)
One study even showed that combining urea and glycerin has a smoothing effect on the skin! (12)
Fun fact: and now you know why I incorporated glycerin into the urea moisturizer 😉
Other amazing things glycerin does:
- It reduces erythema a.k.a. skin redness. (13)
- It retains water in the skin, prevents transepidermal water loss (TEWL), and fights dehydration. (10)
- It helps exfoliate the skin via desmosomal degradation, which is essentially the ungluing of skin cells so they can slough off. (14)
- It protects against irritation, environmental stressors, and strengthens the skin barrier against harsh surfactants like Sodium Lauryl Sulfate (SLS). (15, 16, 17)
- It accelerates skin healing. (10)
And much more! If you want to read a great academic paper that summarizes all things glycerin – check out this PDF.
Closing Remarks
Welp, that summarizes it for this blog post folks! I hope you’ve enjoyed it and have reconsidered giving glycerin a shot…. At least for our urea moisturizer that will be out in a couple months 😉
Warmly,
—f.c.
Great information! It would be great to have a list of products which have glycerin as ingredient and also safe for fungal acne!
I’m an old girl and I’ve been through the wringer with my skin since puberty. I took tetracycline for decades and tried various Rx and OTC topical creams to keep my skin dry. When I was in my late 30s I developed cystic acne so my dermatologist prescribed Accutane and voila, no more acne but very dry skin. However, she also told me to never moisturise to avoid plugging my pores. Now, I have a face full of wrinkles and old acne scars (which look worse as you age because your skin gets drier).
Skin care has come a long way since then. I always moisturise and I have started using tretinoin cream again for plugged pores on my nose and with a faint hope that it might help my wrinkles but while it helps with pores and texture, I have not seen any improvement in my wrinkles. I am completely disillusioned with products developed by cosmetic companies so I just don’t buy them anymore. Short of cosmetic surgery there is nothing available over the counter or even by Rx, for wrinkles and acne scars.
I’m getting to the point which is that I decided to do my own experimenting with various oils and urea, which I picked up on from this blog. Personally, I haven’t seen any improvement in my skin from using urea, so far. I’ve used urea 10% but I can get a 20% concentration, which I will try next. I also decided that I would satisfied if I could improve the just the appearance of my skin with a combination of makeup, to hide the damage, and a moisturiser or benign oil. So I bought a bunch of oils and one of them was glycerin which I wouldn’t even have looked at sideways when I was young. I am pretty impressed with the ability of this oil to make my skin look better *especially if I spray it on after I have put foundation on my face*. My skin looks dry even with a moisturiser and foundation on top (although Vaseline helps). But when I spray a 50/50 mixture of glycerine and water on my face on top of foundation, the glycerine softens the edges of wrinkles/scars and makes my skin glow. It doesn’t last all day but most of the time that’s fine. It also looks a bit oily, but I’m OK with that to
Just my two bits about glycerine and how it has helped me.
Lmao I always appreciate your humor. Great post!
After coming across your website during quarantine (thank God!) I have changed up most of my products, as I have a few different skin maladies caused by Malassezia. Life has gotten SO much better since. One recent change, is that I dropped conditioner all together (since most on the “safe list” still have something that could be irritating). With curly hair this is a big no-no though. Glycerin has been my savior! I started using that as my only conditioner (paired with Mop Top curl styler) and my hair has NEVER been nicer. I’m getting comments on it from everyone I know (even the men!), plus, my hair is insanely soft. I also rub some into my scalp on the worst SD spots, and it really helps. Big fan of glycerin here!
Do you recommend any certain glycerin product?
Got any of that urea and glycerin moisturizer yet?
Sincerely,
LO
Is your skincare line still coming out in 2020?
Just ran to the bathroom and smacked some badass glycerine on my cracked face. Never felt so good 😅
Awesome post!! Immediately dropped what I was doing to read it. (I’m a terrible employee lol) Do you think that a few drops of pure glycerin could be added to a moisturizer before applying? I do this with MCT oil already, but wondering if the same concept applies to glycerin.
What should we look for in a product with Urea (obviously waiting for yours, but in the mean time)?? I tried the hada labo gel moisturizer but I had burning sensation after 4 consecutive days of using it… how do we know its properly formulated?
Is “coconut based pure vegetable Glycerin USP” the same thing/safe to use? Focusing on the words coconut/vegetable. (I have been a user of your website for so long, your content is so helpful in helping me understand the science behind it all, thank you!)
I could cry :’-)
Glycerin irritates my skin if a main ingredient.
I can not wait for your skincare line to come out. I will literally buy each product in a heartbeat. I am so excited! You have no idea how much your blog has helped me, I re-read it all the time. Wishing you all the best.
I hate asking this, because it is probably a really dumb question, but I am very confused about a basic premise here. Aren’t oils and lipids always going to exist on your face because of what’s naturally a part of your skin’s mantel? Won’t glycerin theoretically interact with those? What is the point of avoiding all those ingredients like esters, “ates”, etc. if your skin already contains oils? I see logic in keeping certain ingredients (known comedogenic ones) out, but will total and complete elimination of the other stuff really make much more of a difference? Thanks in advance!
If a product contains arginine and glycerin, would it interact and worsen fa?
Thanks Hailey for translating that paper and thanks F.C for owning up to your mistakes and updating us!!
So I’m hoping someone can explain how sulfate esters (like SLS) are okay. In the case of SLS it’s still using lauric acid which is one of the bad fatty acids, right? I’m hoping it IS okay, because damn near 100% of body washes or shampoos have SLS, or lauroyl sulfate, or pareth sulfate, which is similar. I know there are exceptions to the ester rule and am curious if this is one of them. Thank you so much!
Very informative! Thank you.
Yes, I’ve noticed that a glycerin containing product is way more humectant than the ones that doesn’t. In fact, sometimes I’m able to skip moisturizer when using a serum with glycerin, but no waaaay I could do it if a serum is glycerol free.