Microbiological stability is as important to the shelf-life of cosmetics as chemical stability. For cosmetic producers it is important to have access to the many internationally officially authorised and recognised preservatives available. However, this list is growing ever shorter because of controversial public discussions and increased awareness of the issues surrounding preservatives (MIT, Paraben free etc.). Today a mix of multi-functional and traditional preservatives is standard.

The risk of contamination in cosmetics needs to be managed to avoid 3 typical situations:

  1. The microbiological decomposition of raw and active ingredients in a product can result in bi-products that are not well tolerated by the skin
  2. Metabolic bi-products from microbes can irritate the skin (more or less aggressively depending on skin condition)
  3. Visible microbiological activity – not acceptable under any circumstances

The rule when using preservatives is “as little as possible, but as much as necessary”. This is so that the right balance can be reached between product effectiveness and skin tolerance.   This careful balance needs to be found as we want to avoid the development of microbes but we also don’t want to introduce sterility to the skin´s microenvironment which would shift the skin out of its natural balance and cause other problems.

During product development, a lot of possible variations and combinations are tested. Through short-term / business-driven decisions about active ingredients, a finely balanced preservation system can be kicked out of balance. This can even lead the development team back to square one in product design costing time and money.

Our concept at Cosmacon is to approach your product with a 360° screening of your basic formulation, and to give you an “effectiveness range” to support short-term ingredient decisions. We can:


  1. Check your formulation
  2. Check microbiological studies to date
  3. Suggest new systems
  4. Perform screening tests
  5. Adjust the preservative system as required
  6. Perform full-test and stress tests on a scaling up batch


For an evaluation of your current testing concepts and to access our expert network of testing institutes just contact us.