Better cosmetics thanks to better microbiome models

Essen, Germany. Evonik has developed a new model of the skin microbiome. For the
first time, this model allows a scientifically substantiated evaluation of the influence of
cosmetic ingredients and products on skin microbiota in laboratory tests. The company
is currently testing cosmetic ingredients from its own product portfolio to obtain
evidence-based information on their microbiome-friendliness. Cosmetic producers
and consumers are increasingly interested in scientific evidence of the efficacy of
cosmetics. In addition, the data will give Evonik a basis for developing even better
cosmetic ingredients.

The skin microbiome—comprising all bacteria, fungi, and viruses found in the skin—
varies from one person to another. It is exposed to many internal and external
influences, from diet to sunlight. The occurrence of specific strains of bacteria is
characteristic of certain skin zones, which can be described as sebaceous, moist or dry.
“Many modern cosmetics advertise that they are microbiome-friendly,” says Stefan
Pelzer, who is responsible for microbiome research at Evonik. “However, the tests
used at present do not fully replicate the complexity of the skin microbiome.” As a
rule, the impact of the ingredients of a cosmetic product on individual strains of bacteria is screened. The complex interaction between microorganisms is not taken
into account.

By contrast, Evonik’s new skin microbiome model looks carefully at precisely these
interactions and mutual interdependencies in the laboratory. For this, between eight
and ten typical skin microbes are co-cultivated. In other words, the conditions are
chosen so that all strains of bacteria can proliferate and interact. That is a specific
strength of this new approach.

Parameters are the increase or decrease in the biomass and changes in the diversity of
the cultures for a test substance compared with a control. They are then entered in an
evaluation matrix as “microbiome-boosting,” “microbiome-friendly,” “microbiomemodulating,”
or “microbiome-impairing.” Every significant change in the diversity of
the bacteria is regarded as adverse because the protective function of the skin
microbiome depends on the natural equilibrium of the microorganisms.
The microbiome consortium is grown on microplates. These standardized plates allow
investigation of 48 individual samples simultaneously. Moreover, this is quantifiable
and cheaper than previous methods. Pelzer: “Our new model closes the gap between
simple but less meaningful conventional in-vitro tests and more time-consuming invivo
studies on test persons.”

In addition to the co-culture model for balanced skin, Stefan Pelzer’s team has already
developed a model for skin that is susceptible to acne. Further models are to be
developed in collaboration with customers in the cosmetics industry. Moreover, work
to enhance complexity has already started. One possibility would be combining the
bacterial co-cultures with tissue and cell culture models. After all, as Pelzer explains,
microorganisms do not simply interact with each other; they also interact with the skin
cells.

The scientific findings are of relevance for a large market. Experts estimate that global
retail sales of cosmetic and care products will be around US$460 billion this year. By
2027, that could increase to around US$580 billion. Scientifically substantiated
efficacy claims will be key to this growth. According to a recent study, one in two younger consumers obtains extensive information on product benefits and ingredients
prior to making purchases.

Evonik’s expertise is pooled in its own Biotech Hub and Skin Institute. The Biotech
Hub brings together Evonik’s competency in biotechnology. This includes an in-depth
understanding of complex biological systems such as the gut microbiota and skin
microbiome and of biotechnological production processes. About 150 employees in
Hanau and Halle (Germany) and Shanghai (China) are working on biotechnological
approaches to sustainable solutions for a healthy life and a healthy planet—known at
Evonik as Biosolutions.

The role of the Skin Institute, which was established in 2023 and comprises a network
of laboratories in Singapore, India, Spain, and Germany, is to provide evidence of
dermacosmetic claims for Evonik’s present and planned portfolio of cosmetic
ingredients. Dermacosmetics are cosmetic products containing active ingredients with
well-defined and scientifically substantiated benefits for the skin. A claim describes
these benefits and is also used to promote the products.