Test of the Month!
XtraMild: the industry-leading in vitro test for credible scientific data supporting mild and gentle claims.
Dr Carol Treasure, Founder of XCellR8
Sensitive skin is a global concern. A systematic review published in the Journal of the European Academy of Dermatology and Venereology, covering 26 studies across 18 countries and over 50,000 individuals, found that 71% of adults globally report some degree of skin sensitivity, with 40% reporting very or moderately sensitive skin (Chen et al., 2020). That was the picture in 2020. It’s safe to assume the numbers are higher now. Research presented at the European Academy of Dermatology and Venereology Congress in 2025 found that sensitive skin prevalence has risen by 68% over the past two decades, driven by modern lifestyles, stress, pollution and urban living (Galderma/EADV, 2025).
The implications for the beauty and personal care industry are significant. With the majority of adults experiencing some degree of skin sensitivity, “mild” and “gentle” have moved from nice-to-have claims to front-and-centre selling points. But how do you prove it?
That’s the question XtraMild was built to answer.
What is XtraMild?
XtraMild is our proprietary in vitro mildness test, developed with funding from Innovate UK. It uses a reconstructed human skin model with extended exposure times to consistently identify even the subtlest differences between ultra-mild formulations, differences that standard regulatory tests were never designed to detect.
Standard OECD skin irritation tests were developed for hazard identification and chemical labelling. They serve that purpose well, but they aren’t sensitive enough to distinguish between the gentlest surfactants, formulations and finished products. XtraMild fills that gap.
How does it work?
Ingredients or formulations are applied to a reconstructed human epidermis, the closest in vitro simulation of real skin. Cellular viability is measured over extended timepoints, generating two key outputs:
- Irritancy classification: placing products into categories from Severe through to Minimal/Non-Irritant.
- Mildness ranking: a continuous measure that allows direct comparison between formulations, enabling you to see exactly where your product sits relative to others.
What makes it powerful?
The real strength of XtraMild is in how the results can be used:
- Rank ordering candidate ingredients, blends or formulations to support NPD decisions about which option to take forward.
- Benchmarking against market leaders, understanding how your product stacks up against other brands. We hold an extensive anonymised reference database across a wide variety of product types, including many leading brands.
- You can also build in your own choice of benchmarks for direct comparison.
Validated against human data
XtraMild has been directly validated against human patch tests. Across multiple industry case studies, products were consistently ranked in the same order of mildness as the clinical data. That means you can trust that the in vitro ranking reflects real-world performance on human skin.
This contributes to XtraMild’s superpower: screening products before committing to expensive clinical studies and giving early confidence that a formulation will perform well with volunteers. It also generates stand-alone supporting data for “mild,” “gentle,” “suitable for sensitive skin” and similar claims.
Who uses it?
XtraMild is trusted by industry leaders including PZ Cussons, Lush, Unilever, Bulldog, Marks and Spencer, Oriflame, The Body Shop and ingredient suppliers Innospec and Holiferm, as well as SMEs including sensitive beauty company Harborist and surfactant manufacturer Lankem. Whether you’re a global brand or a start-up, the test is designed to work for your needs and your budget.
Beyond skin
We don’t stop at skin. We’re also established experts in testing the mildness of formulations on the eye (baby shampoos, eye creams, micellar waters), the oral mucosa (toothpastes, mouthwashes) and the vaginal epithelium (intimate washes, bath products). Where mildness is a priority, we can assess it.
Special offer
To celebrate our Test of the Month, we’re offering special discounts on XtraMild for orders placed throughout the month. If you’re not ready to test yet, you can place your order now to secure your lab slot and take advantage of the lower price. Discounts vary according to the number of items to test.
We’d love to help you build the evidence behind your gentle claims. Get in touch and we’ll talk through the best approach for your product.
Find out more. Email info@x-cellr8.com. Call +44 (0)1925 607 134.
References
Chen, W., Dai, R. & Li, L. (2020). The prevalence of self-declared sensitive skin: a systematic review and meta-analysis. Journal of the European Academy of Dermatology and Venereology, 34(8), 1779-1788.
Vidal, S. et al. (2025). Defining the Prevalence, Clinical Characteristics, and Demographic Influences on Patients with Sensitive Skin Syndrome. Poster presented at the EADV Congress, September 2025, Paris, France.
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Contact us if you’d like to learn how you can support our mission, become a corporate sponsor or donate to our crowdfunder.
Email info@x-cellr8.com
Call +44 (0)1925 607 134.
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