The microbiome is one of the fastest growing trends in the beauty industry and a major area of scientific interest.
The popularity of the microbiome concept really started gaining traction back in 2012, when the Human Microbiome Project (HMP) was completed, changing the understanding of the body’s microbial ecology. The skin microbiome, in particular, has become a key focus over the past decade within the dermatological and cosmetic fields alike.
Understanding the microbiome and the role of microbiota to maintain its delicate balance is an essential step to gain insight into the mechanisms responsible for keeping the skin in good condition. For over a century, we have fought invisible microbes, seeing them as ‘bad’. Now, it’s time for us to see them as an essential part of our wellbeing.
There are already a number of brands and products that focus on microbiome modulation to improve skin health. Research has shown the benefit of using ingredients that feed our healthy bacteria (‘prebiotics’) and digested components of bacteria (‘postbiotics) in skin care.
Studies are also increasingly showing the benefits of using live bacteria (‘probiotics’). Yet, with new developments come new challenges: how do you regulate a new generation of skin care products?
How do we distinguish between pre, pro and postbiotics?
In order to get to grips with the microbiome – skin and otherwise – it is important to understand some key scientific terminology. Prebiotics, postbiotics and probiotics are three such terms that often get used interchangeably, despite having very different meanings (see more on these here!).
According to the consensus definitions provided by International Scientific Association for Probiotics and Prebiotics (ISAPP) & Food and Agriculture Organization (FAO), prebiotics, probiotics and postbiotics can be defined as the below:
- Probiotics are defined as living microorganisms (friendly ones) and are fully accepted as ingredients in food and nutritional supplements for aiding the gut microbiome. Still, the term is often misused to name prebiotics and postbiotics – both of which, in contrast, are not viable or capable of growing (cannot have metabolic activity or form colonies).
- Prebiotics are substrates selectively utilised by the microorganism host (a kind of fuel for microbes)
- Postbiotics are non-viable bacterial products or metabolic byproducts from probiotic microorganisms
How are these ingredients being used in cosmetics?
As with all cosmetic ingredients, prebiotics, probiotics and postbiotics must fulfil the key cosmetic principles. However, there is no specific policy, regulation, or guidelines regarding these ingredients in cosmetics in relation to the microbiome as of yet.
Indeed, though the skin microbiota cannot be separated from the skin, in cosmetic regulation, the skin microbiome/microbiota is not yet defined or even described. Is it just a matter of time before we transfer these scientific findings into the legal texts? Or at least refer to existing legislation (definition, safety) as outlined for the healthcare and/or food sectors?
Most importantly, it should be noted that these ingredients are not prohibited (e.g not listed in annex II of the EC12323/2009) and can be safely used.
Therefore, they can be considered “classical ingredients”, and thus need to comply with the cosmetic definition and key principles.
Prebiotics and postbiotics can be, and are already, used and regulated as cosmetic ingredients in this way as they are non-viable. Probiotics, when used as cosmetic ingredients, aim to protect the skin from external influences and nourish healthy bacteria to influence skin pH or hydration, for example. Consequently, in the absence of cosmetic policy around probiotics, live organisms can, for now, be considered classical cosmetic ingredients falling under this umbrella definition.
It is worth mentioning that a joint working group (more on this below) was created in 2018 to discuss probiotics-based products in the cosmetic sector. With representatives from different countries and jurisdictions, the group has identified the potential need for development of internationally-accepted guidelines for terminology, safety and quality.
Firstly, let’s look at the key principles in the cosmetics framework:
Cosmetic key principles and probiotics
If we look at the cosmetic framework, each country has its own definition for what constitutes a cosmetic product but there are similarities in criteria, such as site of application and cosmetic function.
As such, to be considered a cosmetic product, a product must encompass the following:
- Site of application: The product must be used on an external part of the body, e.g. the epidermis (top layer of skin), nails, teeth, hair, lips, and external genital organs
- Function: The function of the product is to clean, beautify, correct body odours, or otherwise keep the body in good condition
While probiotic-based products meet the criteria above, the cosmetic key principles include additional factors such as safety, microbiology quality, and substantiated claims, as well as shelf life and packaging – the current regulation for which does not take into account live bacteria (note – by no means does this mean that probiotic products are not safe or high quality).
- Safety: A cosmetic product (and its ingredients) must be safe for the intended use
A safety assessment is a mandatory requirement in EU cosmetic legislation (and widely requested by companies and regulators in North America, ASEAN countries and China) as evidence that the product is safe for use. Safety is under industry responsibility.
Probiotics are live organisms that are dynamic and thus, are unlike chemicals. As such, as an industry, there is a need to adapt and design a safety assessment that is applicable to probiotic-based cosmetics. For example, it is essential to prove that the microorganism used does not produce toxins, prove the absence of pathogenicity, and determine both antibiotic resistance and metabolic activity – common criteria for a similar safety assessment in the food sector.
- Microbiology quality: Cosmetic products are not expected to be sterile and they shall not contain excessive amount of microorganisms (specified pathogenic microorganisms)
Microbiology quality is described in the Scientific Committee on Consumer Safety (SCCS) guidance in the EU: even if not legally required, this microbiology test is necessary in order to guarantee the quality of a cosmetic product and safety for the consumer.
How well probiotics fit the microbiology requirements that generally apply for all cosmetics remains unclear. Microbes are mainly considered as contaminants, with a focus on pathogenic microbes, as cosmetics are formulated so as to minimise their growth. It is, therefore, important to educate both authorities and consumers alike on friendly, intentionally added microbes i.e. probiotics.
- Claims: Cosmetic claims must be substantiated, and not misleading
In the context of calling a product probiotic, this means that the final cosmetic product produced must contain probiotics and, importantly, the probiotics must be alive during the product’s full shelf life.
Increasingly, products on the market contain claims that they contain probiotic ingredients, yet, as aforementioned, surveys have shown that many of these marketed products contain primarily postbiotics and prebiotics rather than live bacteria.
As a result, unappropriated use of different terms related to probiotic, prebiotic and postbiotic is creating confusion around probiotic-based products.
Developing internationally accepted definitions of key terms to be used consistently is, therefore, absolutely crucial to minimize confusion and avoid misleading regulators and consumers alike. (Note – in the food and nutrition sectors, each European country has its own country-specific rules for labelling; in some European countries products cannot even put the word ‘probiotic’ on a label.)
As such, the International Cooperation on Cosmetic Regulation (ICCR)’s ‘Microbiome and Cosmetics’ joint working group [in which I am a member through my role at DSM] is working to educate key audiences to bring increased understanding and awareness to cosmetic products that target the skin microbiome. Further, the group aims to provide recommendations in this area – including ensuring clear and consistent ‘biotics’ terminology.
Probiotics have made a name for themselves when it comes to helping the gut microbiome and it is only a matter of time before we can say the same within skin care.
Definition of a cosmetic differs from one country to another one: globally a cosmetic product is substance or mixture of substances (ingredients) intended to:
- Be placed in contact with the external parts of the human body (epidermis, hair system, nails, lips and external genital organs) or with teeth and the mucous organs of the oral cavity
And aims mainly at changing the appearance and or keeping in good condition
- For cleansing, beautifying, promoting attractiveness
- Improving or altering the complexion, skin, hair or teeth
- Correcting odor
Based on regulation in different countries, we summarize the main key cosmetic principles for cosmetic ingredient & finished cosmetic
The intended use of the ingredients (Substances or mixtures of substances) must be in line with the cosmetic definition and comply with key cosmetic regulatory principles:
- To be applied at the external part of the body
- To keep in good condition, to clean, beautify or correcting body odor
- To be safe for intended use
- Microbiology quality
- Stability & shelf life
- Claims must be substantiated
- Good Manufacturing Practice (GMP) and appropriate packaging
For more definitions, visit our Skin Microbiome Basics page here.