When a Reddit post from months ago about a customer finding mold in Kosas’ concealer appeared on TikTok, it sparked debate among consumers about the clean beauty movement sweeping the cosmetics industry.

Using “minimum ingredients for maximum impact,” Kosas claims that its products are “skin-improving.” Kosas is one of many clean beauty brands that claim their products are devoid of parabens, phthalates, sulphates, talc, aluminum, and a slew of other chemicals that are frequently found in cosmetics.

Revealer Concealer from the company has been hailed as a must-have item for anyone attempting to achieve the “clean girl aesthetic,” a fashionable beauty look that promotes “no-makeup” makeup and carefree, slicked-back hair.

However, some TikTok users have recently complained that their concealer has started to smell rancid and has irritated their skin. As their videos gained popularity, a rumour that the Kosas product had mould growth also spread, which increased criticism of the company and the clean beauty movement as a whole. Some users on TikTok and Reddit have questioned the safety of clean beauty products as a whole as the videos continue to go viral.

The claim regarding the concealer appears to be related to an eight-month-old Reddit post in r/Makeup, where the original poster claimed they discovered “black spots” and a “blue cheese” odour in their concealer more than a year after opening it. They also said that when they tried the product, their skin got burned.

A Kosas representative pointed NBC News to the company’s FAQ page when asked about the product’s online criticism, which states that Kosas uses “safe, effective preservatives and antimicrobial stabilisers which prevent against mold, yeast, and pathogens.”

Additionally, the company has responded directly to some of the complaints in TikTok comments. The Kosas brand account explained that the discoloration in the concealer was simply the concealer separating and “clinging to the sides” of its packaging after a user posted a video of her concealer and questioned whether the mould in the product was the cause.

Every brand experiences setbacks, according to Jane Tsui, a cosmetic chemist who oversees product formulations for cosmetic companies, and Kosas is probably getting so much negative press because “they have been such a fast-growing popular brand.”

The Point After Opening (PAO) symbol, which denotes the product’s useful lifetime after opening, should be present on cosmetic packaging. The PAO on the Revealer concealer states six months, so after that time the product might no longer be stable.

Tsui advised customers to regularly check their products after their PAO date, especially if they begin to smell or produce new skin irritations, because it is “unrealistic” to expect people to replace their makeup so frequently.

ingredients are more dangerous because they are artificial, but that is simply untrue, according to Tsui. To ensure their safety, “a lot of research has been done on it.”

The preservative parabens, which is frequently used, has been related to higher oestrogen levels, and one study found the chemical in breast cancer tissue. The beauty industry has mainly avoided the use of parabens, despite the fact that studies into the chemical’s long-term impact on health are still preliminary. However, alternatives to preservatives may still be dangerous, unpleasant, or less effective. The Food and Drug Administration posts microbiological contamination notifications for beauty products on its website, and Glossy reported a spike in these reports in 2019.

On popular cosmetics subreddits, users have discussed whether the clean beauty movement is beneficial for people with sensitive skin or if it’s just a “marketing gimmick,” as some makeup fans seem to be getting tired of the broad claims that some clean beauty brands make.

Users slammed the brand Saie for an Instagram post outlining the substances it doesn’t use in its products, like mineral oil and petrolatum, in a recent Reddit thread in r/MakeupAddiction. Petrolatum, the primary component of Vaseline and Aquaphor, was mentioned by some customers as a key component in their skincare regimens.

A Reddit member left a comment on another thread saying, “A lot of ‘clean’ beauty products also smell TERRIBLE.” “Yes I’m looking at you Ilia, and your hamster-cage-scented tint.”

Requests for comment from Saie, Ilia, Vaseline, and Aquaphor representatives were not promptly fulfilled.

Tsui claimed that while many of her coworkers and she support the clean beauty movement, brands themselves “don’t have a strong reason” to forego traditional cosmetic components.

“Instead of going the clean route, personally, I would love to see more education around specific ingredients,” Tsui stated. “Rather than saying ‘fragrance-free, sulfate-free, paraben-free.’ A ‘free-from’ ingredients list, I think, is more harmful than just explaining why something is in there.”