The patent behind a $182 cult-favorite skincare product recently expired. So, where are all the dupes?

Business Insider

20-05-2025

Does it sound crazy to spend $182 on a 30 mL bottle of face serum that famously smells like hot dog water?
Tell that to the diehard fans of SkinCeuticals' C E Ferulic.
Despite its high price point, the L'Oreal -owned brand's vitamin C serum has developed a cult following of devoted users over the past 20 years, thanks in part to a closely guarded, patent-protected formula that the company says can protect skin and improve signs of aging.
Months ahead of the patent's expiration date in March, skincare addicts flooded Reddit with hopes of cheaper "dupes" — a comparable product at a more affordable price point.
But the expiration date of that patent has come and gone, leaving many wondering: Where are the dupes?
Skincare industry experts who spoke to Business Insider said lookalike products could be on the way, but they don't expect the patent expiring to immediately result in any major disruptions to the industry, the vitamin C market, or the SkinCeuticals brand itself.
A bigger issue, they say, is the effect of dupe culture on skincare industry innovation — the kind that led to the existence of C E Ferulic in the first place.
The patent factor
SkinCeuticals' C E Ferulic is beloved by celebrities like Hailey Bieber and embraced by many skincare fans as the holy grail of vitamin C serums — sometimes a little begrudgingly, due to the high price.
Niki DeMartinis, an ER doctor who lives in New York, said she has tried various vitamin C serums over the years, but that she always comes back to C E Ferulic.
"I feel like my skin looks and feels the best with it," she told BI, adding it makes her skin look more even and less dull. She said it's the priciest skincare product she uses regularly, but she thinks it's worth the cost.
C E Ferulic, which hit the market in 2005, is 15% L-Ascorbic Acid, or pure vitamin C, with vitamin E and ferulic acid. Dr. John Carroll Murray, a dermatologist at Duke University who authored a 2008 study showing the formula provided UV photoprotection for skin, said the reason C E Ferulic was such a big deal was the way it was put together.
"It's easy to put vitamin C into a product. It's quite common, quite cheap, and quite safe, but it has to be properly formulated so that it'll be active and effective at removing reactive oxygen species," he said, referring to molecules that can damage skin.
Lina Twaian, a skincare industry expert and brand consultant, told BI that the ability to tout the patent has been a useful marketing tool for SkinCeuticals.
L'Oreal, the largest beauty company in the world, clocked $47 billion in sales last year, according to its annual financial report published in February. The report said its dermatological beauty division grew nearly 10% in 2024 and that the SkinCeuticals brand grew by double digits.
SkinCeuticals' patent for C E Ferulic officially expired in March, the standard 20 years after it was issued. Since then, the company has removed several references to the patent from its product page, according to a review of internet archives. They're now touting the previously "Patented Formula with 15% Vitamin C" as a "Superior Formula."
When reached for comment on the patent expiring, SkinCeuticals told BI the brand is introducing a new, patent-pending "antioxidant protection and performance" formula in 2026.
The brand said in a statement that "SkinCeuticals remains the only brand with exclusive expertise in the precise formulation and production of C E Ferulic."
Experts are divided on whether more dupes are on the way
As dupe culture exploded on social media over the past five years, there's been an even greater appetite for cheaper alternatives to C E Ferulic.
"It's been such a popular and efficacious product, it's pretty clear that brands are going to try to duplicate that," Kelly Dobos, a cosmetic chemist and professor at the University of Cincinnati, told BI of the patent's expiration.
She and the other industry experts said brands have already released their own versions of vitamin C serums, including some that appear similar to SkinCeuticals'. That's because even changing a product slightly can make it safe from a potential patent infringement, according to Larissa Jensen, a senior vice president and global beauty industry advisor at Circana.
"If you have something that's close but not exact, it can still be used in the market, so I don't necessarily know if the patent expiring is going to all of a sudden expose a floodgate of brands with this formula," Jensen told BI.
Still, L'Oreal has fought to protect the formula.
In 2018, L'Oreal sued Drunk Elephant, alleging the skincare brand's vitamin C serum had infringed on its patent. The case was settled out of court, and the terms of the settlement were not made public.
Drunk Elephant, which is owned by the Japanese beauty company Shiseido, sells its C-Firma Fresh Serum for $79, less than half the price of C E Ferulic. The product has 15% vitamin C, 1% vitamin E, and 0.5% ferulic — the same quantities promoted by SkinCeuticals. However, unlike C E Ferulic, the product is designed to be mixed by the consumer before use.
Shiseido told BI it does not comment on company settlements or litigation as a matter of company policy.
Since the patent has expired, Dobos said she expects brands to try to replicate the formula, now without the risk of patent infringement. But she said there's no guarantee that those companies will get it right or that, even if they do, they'll be able to do it at a significantly lower price point.
Not all dupes are created equal
Replicating C E Ferulic won't necessarily be easy, Dobos said. In part, that's because it's unlikely the patent told the full story of how the serum is formulated and made.
There are also many other factors that could impact the effectiveness of a product: the quality of ingredients, the manufacturing process, quality control and assurance, and packaging, which needs to be compatible with and protective of the formula.
Producing effective skincare can also be very finicky, so every aspect matters, Dobos said, adding that without clinical trials on a specific product, it's unclear if it will have the same effect as a product it appears similar to.
Elf Cosmetics announced a new vitamin C serum earlier this month that Dobos said appeared to be positioned as a direct competitor to C E Ferulic, for 91% cheaper. The $16 Bright Icon Vitamin C + E + Ferulic Serum has a similar trio of main ingredients, but at a fraction of the cost, and is being marketed as an alternative to "spendy serums."
But Dobos said it uses a different version of vitamin C, 3-O-Ethyl Ascorbic Acid, which she said was a "more stable version, but it's less substantiated in terms of effectiveness." Other factors that could impact the difference in price include where it's made (Elf produces most of its products in China), regulatory and labor costs, the cost of ingredients and packaging, and research and development, like clinical studies, Dobos said.
Clinical studies would be needed on the Elf product to really compare it to C E Ferulic, she said.
Elf did not respond to a request for comment.
Taking the shine out of dupe culture
Several industry experts have said that dupe culture itself could actually be hurting skincare innovation. Charlotte Palermino, the cofounder of Dieux Skin, recently wrote in a Substack post that dupes have "diluted" the beauty industry. She said innovation is expensive to produce as well as protect.
"But the tragedy of dupe culture isn't just the heartbreak of 'they copied my homework.' It's the slow death of innovation," she wrote, adding, "If you want innovation, perhaps consider valuing it."
Dobos said dupe culture incentivizes companies to focus on putting out products that are in line with the latest trends rather than creating something truly groundbreaking.
"I do think the kind of dupe culture that we're in is hindering innovation in a way because it's taking time and resources away from it," she said. "True, disruptive innovation takes time."