"It smells like blue cheese": What you need to know about those 'mouldy' concealers.

Oh, you're eating? You might wanna... put that down for a minute. Because we really need to talk about the complaints of alleged mouldy, smelly concealers from cult makeup brand Kosas.

In case you've missed everything that's been going down on social media, let us bring you up to speed. 

The popular cosmetic brand is facing claims from people who say they’ve found mould in their liquid concealers. The product in question? Kosas Revealer Concealer ($50) - that viral concealer that blew up last year when the ‘clean girl’ beauty aesthetic started trending. 

@talliyhaa

Dont ask me if my kosas concealer has mould i dont want to talk about it

♬ Ac r7sheed - rhy 🎸🍃 🕸️

Favoured by celebrities such as Hailey Bieber and beauty influencers like Mikayla Nogueira, the concealer has racked up more than 13 million views across TikTok and is known for being the perfect product for mastering that minimalist 'no makeup' look. 

It's also formulated with lots of skin-loving ingredients such as hyaluronic acid and peptides, as well as calming arnica - so it's a real skincare/makeup hybrid.  

Whether you've tried this particular concealer or not, chances are if you're a beauty fan you're across Kosas' products. The brand is popular for good reason.

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A post shared by Kosas (@kosas)

However, cult status or not, this recent controversy is proving that when it comes to beauty brands and social media backlash, the internet is not going to hold back when things go wrong. And naturally, people want to hold brands accountable.

Watch: Can't find a concealer to match your foundation? Here's a nifty trick. Post continues below.

Let's go back to 2022 - because that's how long this has been bubbling away at the surface.

It was in June last year when a Reddit user by the name of "veryangryorchards" said that after nine months of using the popular Kosas concealer, they "started to notice a blue cheese smell." 

"Fast forward to a year later, I put it [on] and my eyes and face BURNED. I figured it’s probably done for anyway, because concealers usually last one to two years, but I went back to use this a couple of weeks later and I found black spots in my concealer," they continued.

In a follow-up post in the comments, the poster said: "The first tube of concealer was bought last April. That is the one that has the 12-month expiration sticker, and the one that has black mould. The new one had a sticker of six months, which made me worry that it will go bad even faster, which is why I returned it (or tried to)."

But wait. There's... more.

Over on the brand's TikTok account, the comment section was swimming with people sharing their experiences of noticing funny smells and finding mould in the concealers. 

There were also claims of users experiencing 'irritation', 'rashes' and 'hives' from the product. 

@lexi_rowe1 Replying to @Rylie Booth ♬ blow your mind - 🕸️

One user wrote: "My Kosas concealer went rancid within 3 months of use."

Yikes.

Another wrote: "Do your products actually grow mould?", while another follower quipped: "Out with the old, in with the mould."

@kosas OUT: being sad beige bbys 😔 IN: Living in color 🎨 #kosas #cleanbeauty #glowup #bringingcolorback #newyearnewme #CapCut ♬ original sound - 𖡼𖤣𖥧𖡼𓋼𖤣𖥧𓋼𓍊

While there's obviously no real way to verify if every single one of these claims is true, the backlash now has consumers questioning the shelf life and ingredients of Kosas products.

The brand responded to one of the comments on TikTok, stating: 

"As a clean makeup brand, we’re serious about quality and testing. We use preservatives that are alternatives to the most commonly used ones in mainstream cosmetics, that are safe for sensitive skin and powerful against mould and pathogens."

"Each Kosas product has an expiration date which will vary from two to three years. We will always work diligently to always ensure that our products are safe for consumers to enjoy!"

Preservatives are included in products to prevent them from getting contaminated by things like mould, yeast and harmful bacteria. 

These can get into your products and rapidly start growing, even if the product itself still looks and smells okay.

If you put contaminated products on your skin, this can then obviously lead to a host of different concerns - such as irritations, reactions and infections.

However, off the back of the recent 'greenwashing' beauty trend over the past few years (read: 'natural' this and 'chemical free' that), the views and opinions on preservatives have changed, with many consumers now seeing them as dangerous and 'bad' for your health. 

Which is... entirely unproven.

Because just for the record, preservatives are not bad. In fact, as mentioned before, they're actually essential in order to be formulating safe, effective cosmetics.

While there are no specifics as to what Kosas means when they say they use "preservatives that are alternatives to the most commonly used ones in mainstream cosmetics," Dr Michelle Wong from Lab Muffin Beauty Science discusses the use of alternative preservatives in skincare.

She told Mamamia, "Clean beauty demonises a lot of really effective preservatives, so many clean brands end up using less robust preservatives systems. Over the years we've seen a lot of microbial overgrowth issues from 'clean' brands."

"The concealers have a doe-foot applicator, which means the product needs a stronger preservative system to protect against the repeated introduction of microbes from people's faces and the air into the middle of the product."

In a TikTok video, LA-based cosmetic chemist Javon Ford weighed in on the controversy, saying it "starts an interesting conversation on why brands can't be too clean in the ingredients they put in their formula."

He tells his followers: "Let's take a look at the preservative system. This formula uses two preservatives: potassium sorbate and sodium benzoate, both food grade preservatives."

Still with us?

"However, they're not usually associated with being broad spectrum. Broad spectrum preservatives are preservatives that can control the growth of gram-positive bacteria and yeast and mould. These two preservatives are better at killing fungus and mould than they are at killing bacteria."

@javonford16 Replying to @itsnanacastro #cosmeticchemist #kosasconcealer #skincare ♬ original sound - Javon Ford

He goes on to say this product is not formulated at a pH of below 5.0 - and potassium sorbate can be really irritating to some people's skin at low pH levels.

He also points out that the formula is actually missing a certain compound that's pretty crucial to correctly preserving a product. 

"Does this mean it's improperly preserved? I can't say - but none of my bosses would've ever let me pass up a formula like this. Lastly, I want to say - parabens wouldn't have this problem."

Another cosmetic chemist by the name of @janethechemist said: "I see here that Kosas is using potassium sorbate and sodium benzoate as their main source of preservation. I, as a formulator, don't think that's enough."

Check out her video below:

@janethechemist Have you guys heard about this?! 😳 #cosmeticchemist #kosas #mold ♬ original sound - Jane

Not only does the backlash have people questioning the shelf life of Kosas products and the formulation itself, but also 'clean' beauty products as a whole. 

Is this what happens when brands don't use stable preservatives? Is it a trade-off for using 'clean' beauty?

Dr Wong told Mamamia, "I think one big issue with 'clean beauty' is that it overestimates more sensational but theoretical health risks like cancer and endocrine disruption, and underestimates more mundane but more concrete risks like microbial contamination."

"Preservatives like parabens were introduced because of issues from microbial contamination in the past, where people have lost eyes and babies have died from infections caused by cosmetic and personal care products."

"Preservatives have been a victim of their own success because it seems like a lot of people have forgotten about these problems. It would be a massive shame if these became significant problems again," Dr Wong warns.

While Kosas has provided various statements in the comment section of their TikTok account, many consumers are angry at the brand's response - which has a lot to do with how the brand/consumer relationship has evolved.

These days customers are becoming more and more switched on about beauty ingredients than ever before (thanks, COVID) - so for many, being directed to an FAQ section of a website isn't enough. As an indie beauty/Gen-Z-approved brand, people are expecting more.

So, what should Kosas be doing in response to this situation?

On Instagram, Beauty Independent actually asked this very same question. That is, how should Kosas be reacting to social media allegations?

And the answers - from public relations, marketing experts and cosmetic chemists - were pretty on point.

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A post shared by Beauty Independent (@beautyindependent)

We think this comment from AJ Addae of Sula Labs really hit the nail on the head: "This would be an interesting opportunity for Kosas to potentially lead the way in moving the goal posts of redefining what the future of clean beauty could look like."

So, should the brand be looking for ways to actually solve the issue? For example, should they make the tubes smaller so all the products can be used well within the expiration date?

Dr Wong said, "It would be interesting to see the details of their preservative testing if they've done that. It's possible that they could repackage the same formula in lower-risk packaging (e.g. a tube with a small opening) and in smaller pack sizes so people are more likely to use it up within the expected time frame."

Only time will tell.

In the meantime, if your makeup products ever look or smell funny - bin 'em. Stat.

What do you think of the Kosas concealer backlash? Share your take with us in the comment section below.

Feature image: TikTok; @savannahnunues; @lexi_rowe1.

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