How mild is mild?

Existing tests for mildness aren’t accurate enough as they were designed for irritant chemicals rather than today’s gentle cosmetic ingredients. That’s why, in 2017, we embarked on an ambitious R&D programme to develop a new generation of mildness tests.

With funding from Innovate UK, we

  • Optimised existing in vitro and in vivo test methods for maximum sensitivity
  • Demonstrated that in vitro data accurately predicted the rank order of human patch test clinical scores in all studies
  • Established that the in vitro test detects subtle differences between ultra-mild ingredients and formulations

The XtraMild test is now available only from XCellR8 and can be used on a wide variety of products, including novel surfactants, products applied to the skin and baby care ranges.

Download our infographic to see the summary of the research and the fascinating results of our comparison between best selling facial cleansers and soaps.


Why choose XtraMild

  • Credible scientific data for ultra-mild claim support
  • Vegan compliant and cruelty-free
  • Benchmark and rank the mildness of ingredients and formulations within your own brand range or with other brands in your category
  • Limit the need for human volunteers, whether used as a stand-alone test or pre-screen to clinical studies
  • Move beyond a statement of ‘not tested on animals’ to a positive message about using latest technologies to demonstrate product safety and efficacy
  • Lower cost and faster turnaround

Why we need a new test for mildness


The high incidence of stress in our lifestyles puts our inflammatory reactions on alert and makes skin more likely to react. When you add in other contributory factors such as air pollution, poor diet and extreme weather, it explains why the wellness trend has grasped the public imagination so much. The beauty industry is responding with products aimed at soothing and calming the skin.

However, existing tests for mildness were developed for harsh chemicals and weren’t sensitive enough for new surfactants and cosmetic ingredients, leaving scientists without a proven method for distinguishing between ultra-mild test items.



According to Lancome, 91% of consumers in developed countries report that their skin experiences uncomfortable symptoms like tightness, dryness, itching, burning or redness. It’s why formulators are racing to create ever milder products.

Further research published in JAMA Dermatol suggests that as many as 37% of consumers avoid daily life skincare products due to skin reactions. 




Examine the data obtained from in vitro and in vivo tests and results of soap and facial wash comparisons


Listen to our webinar, XtraMild: Understanding Mildness like never before! 


Read more about how we optimised the test method


Read the technical details about how the ET50 method works

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