Editor's note: C&T welcomes this contribution by freelancer and columnist Kacey Culliney, who delves into the patent literature for recent beauty breakthroughs and connects with industry experts to decipher the real-world implications. In this edition of Decoding Beauty Breakthroughs, she is joined by Barbara Brockway, Ph.D., Gill Westgate, Ph.D., and Eva Proudman.
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Editor's note: C&T welcomes this contribution by freelancer and columnist Kacey Culliney, who delves into the patent literature for recent beauty breakthroughs and connects with industry experts to decipher the real-world implications. In this edition of Decoding Beauty Breakthroughs, she is joined by Barbara Brockway, Ph.D., Gill Westgate, Ph.D., and Eva Proudman.
Multinational beauty giant L'Oréal has developed a topical hair and scalp care formulation using a trio of active ingredients to inhibit cortisol and minimize hair loss – a novel push that now needs clinical data, experts say.
Published at the beginning of the year (2026), the international patent1 outlined how a precise blend of Tephrosia purpurea seed extract, niacinamide and caffeine worked synergistically to inhibit cortisol spikes that, in turn, helped prevent or minimize hair loss and thinning. The company said the formula could be manufactured into a rinse-off or leave-on product for use on both wet and dry hair and scalp – for humans as well as animals.
Cortisol and Hair Loss: ‘One Important Root Cause’
In the patent, L'Oréal wrote that many different factors could diminish the quality or quantity of hair over time, including sweat, pollution and dirt. And cortisol – a stress-induced emotional hormone – could be considered “one important root cause toward hair loss.”
Systemic and local cortisol increases, followed by follicular inflammation and follicle damage, could eventually lead to hair loss, the company reported, so it was of interest to explore effective solutions for cortisol inhibition when “caring for the hair and/or the scalp.”
L'Oréal's water-based formula blended three widely used cosmetic ingredients at very specific ratios, and the combined use of niacinamide and caffeine was said to effectively promote the ability of Tephrosia purpurea seed extract to inhibit cortisol levels in a subject. The extract used in the blend, derived from the flowering plant wild indigo, had already demonstrated “unique biological capabilities” in breaking down the cortisol production by skin cells, activating the release of a natural calming neuropeptide acting on mood, and visibly improving skin tone within two weeks, according to L'Oréal. Use in a hair/scalp care formula, therefore, proved interesting.
The company detailed results from in vitro tests of the actives in different ratios in a cell culture medium. Variants achieved between 21-52% cortisol inhibition. L'Oréal reported that findings showed the ratio of Tephrosia purpurea extract to caffeine had to be equal to or less than four, in order to effectively inhibit cortisol.
According to the patent, while a Tephrosia purpurea seed extract was required, derivatives of niacinamide, or vitamin B3, and xanthine could also be used. Additional active cosmetic ingredients that worked to condition and/or care for the hair and/or scalp could also be incorporated, along with any desired fragrances or preservatives.
The same findings and details were published in a French patent filed by L'Oréal around the same time.
The Expert Eye: Clinical Trial Data Required
Three independent experts were contacted to understand the potential of L'Oréal's patent for future hair and scalp care products targeting hair loss.
“The jump between demonstrating a significant drop in cortisol to preventing or reducing hair loss and therefore maintaining or improving hair quantity/quality really needs to be supported by real-world or, better still, clinical evidence,” said Barara Brockway, Ph.D., cosmetics and personal care scientific advisor and owner of Barbara Brockway Consulting. “... Long-term, placebo-controlled clinical trials on human subjects are needed to bridge the gap between biological hormone inhibition and a measurable/visible cosmetic improvement.”
Gill Westgate, Ph.D., director of Gill Westgate Consultancy, agreed: “Whether the blend works in vivo topically is not known from the patent, as no clinical studies are included.” Moving forward, Westgate said it would be important to conduct clinical studies on the blend to track reduction of hair loss in a relevant population – i.e., emotionally stressed individuals – as well as test the three components on human anagen hair follicles ex vivo. Investigating links to hair color could also be of interest, particularly given known links between stress and greying, she added.
According to both experts, in its current form, L'Oréal's patent is novel in its synergistic blend of three well-known active cosmetic ingredients. Brockway and Westgate also agreed the formulation would be most effective as a leave-on product versus rinse-off. “Leave-on is best for achieving any significant deposition and delivery for any product for hair loss,” said Westgate. “However, some data on caffeine from rinse-off products is available.”
Medicine or Cosmetic?
Brockway drew attention to one concern regarding L'Oréal's patent: that it sat very much at “the borderline between a cosmetic and a medicine,” given the company was extrapolating a cosmetic improvement from a biological hormone change. While the careful wording of the patent ensured the invention was a cosmetic designed for hair and scalp care, Brockway said the reliance on cortisol inhibition for the intended cosmetic effect meant the product also sat close to medicine status.
However, given that hair loss remained a very real and devastating experience for many, despite knowledge of molecular biology advancing considerably, innovations in the field had to be welcomed and any work to increase hairspan was always going to “occupy that delicate space between cosmetic enhancement and medical treatment,” she said. Studying the effects of cortisol reduction on human hair represented a “promising research area for improving hair quality,” Brockway added.
Eva Proudman, consultant trichologist and founder of clinic network UK Hair Consultants, said treating hair loss was certainly mutlifaceted and had to be addressed holistically. Per Proudman, while L'Oréal's patent outlined an interesting topical approach – using ingredients “well-known for their anti-inflammatory, stress-reducing properties” – all of the causative factors had to be addressed when targeting hair loss.
“It's important to remember, this type of topical treatment is just one element in a complicated metabolic issue,” she said. “...For me, the key point is that any topical product is only going to treat the localized symptoms and it will not address the systemic cortisol levels that must be addressed alongside the topical-type symptoms.”
Proudman concluded that future research must consider “the whole picture” – beyond a shampoo, serum or cream.
References
1.WIPO database. (2026, Jan 2). Composition for caring for the hair and/or the scalp. Global patent WO2026000229. Patentscope. Available at https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2026000229&_cid=P22-MKL8VM-06904-2
