Today’s busy and sometimes stressful lifestyle can put our inflammatory reactions on alert and makes our skin more likely to react. I know my own skin tends to feel more sensitive in times of stress, or when I’m travelling. Shortcuts in my skincare routine, a lack of sleep, and the brutal dry air of hotels, planes and airport lounges can mean my skin starts to tell me it’s not too happy with the onslaught!  At such times, products that are usually ideal for me can start to cause a reaction. 

I’m not alone. Research published in JAMA Dermatol 1 found a staggering 19.3% of more than 12,000 Europeans surveyed had suffered an adverse skin reaction to a consumer product within the last month, 31.8% within a year and 51.7% in their lifetime, and as many as 37% of consumers avoid daily life skincare products due to skin reactions. When we add societal and environmental factors such as air pollution, poor diet and extreme weather, it explains why our skin needs all the TLC it can get. The beauty industry is responding with products aimed at soothing and calming the skin, with gentle claims front and centre of what many consumers are searching for in a skincare or personal care product.

So how can we ensure that ingredients and products are gentler than ever, whether that’s for baby, child or adult formulations? Traditional skin patch tests can be useful, but many industry leaders have concerns because they don’t yield easily quantifiable scientific data, especially at the mild and ultra-mild end of the spectrum. Clinical studies are valuable to look at differences in response across the population, but earlier in new product development (NPD), lab-based data generated in standardised conditions gives confidence to go forward with expensive projects. 

Standard in vitro skin irritation tests (OECD Test Guidelines) were developed for hazard identification and labelling of chemicals. While they provided a starting point, they aren’t sensitive enough for new surfactants and other cosmetic ingredients or formulations and left the industry without a proven scientific method for distinguishing between ultra-mild items.

That’s why, at XCellR8, we’ve invested years of research to offer in vitro tests that stand out from the crowd and are future-fit for industry. Thanks to funding from Innovate UK, we developed our unique XtraMild test, using a reconstructed human skin model – the closest you can get to a real-life study without risking adverse effects in volunteers. We use extended exposure to consistently pick up the subtlest of differences between ultra-mild skin care and personal care ingredients and formulations. Here’s a snapshot of how XtraMild provides a more complete picture of mildness to support your gentle claims:

  • Validated directly against human patch tests. A variety of products were consistently ranked in the same order of mildness in every case study conducted.2
  • Standardised lab data identifies statistically significant differences between the mildest of formulations.
  • Surfactants tested alone and in combination have supported current knowledge about optimal blends for mildness, and demonstrated the milder characteristics of the latest gentle biosurfactants.
  • Anonymised reference database across a variety of product types, including many leading brands. This is XtraMild’s superpower when it comes to the interpretative power of the test! It ensures real-life context for your results. 
  • The test is used to:
  1. Place candidate ingredients, blends or formulations into a rank order of mildness, supporting NPD decisions about which option to take forward.
  2. Benchmark products against market leaders – understand how your product stacks up against other brands.
  3. Generate stand-alone data or to pre-screen products before clinical testing.
  4. Substantiate mildness and gentleness claims for ingredients and finished products.
  • Like all tests at XCellR8, XtraMild is animal-product-free, enabling companies to generate credible, human-relevant scientific data while upholding cruelty-free and vegan philosophies throughout the supply chain.


As a final note: we don’t stop at skin! We’re also established experts in testing the impact of gentle formulations on the eye (such as baby shampoos and eye creams), the mouth and gums (such as toothpastes and mouthwashes) and the vaginal epithelium (for intimate washes and bath products).

I’m very proud of all the research that has gone into XtraMild at XCellR8 and we love helping companies across the global industry to support their claims for mild and gentle products! If you’d like to find out how to join the growing number of companies trusting in our animal-free data, our expert scientists and I would love to chat with you, and we’re great listeners! We’ll always put your needs at the centre of the conversation and give you the best possible advice on how to get that all-important claim support data, whether you’re an ingredient supplier, global leader, or brand-new start-up. We understand your products are as unique as you are! 😊

Find out more 

1 Naldi et al (2014). Prevalence of self-reported skin complaints and avoidance of common daily life consumer products in selected European regions. JAMA Dermatol. 150(2): 154-162.

2 5 industry case studies, 4 test items each in the Innovate UK-funded project.


Written by Dr Carol Treasure, Founder of XCellR8


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