Biofilm modality and the skin microbiome space

Rachel Grabenhofer is the Managing Scientific Editor of Cosmetics & Toiletries (C&T) the premier, peer-reviewed trade journal for cosmetic and personal care research, development, formulation and inspiration. Rachel is also conference co-director for the Beauty Accelerate event, aligning cosmetics research and development with business and marketing for stronger brand collaborations.

In her 20+ years on the brand, she has served as conference program director for various C&T Summits, participated as a subject matter expert in internet radio interviews, and acted as a manager and judge for in-cosmetics Innovation Zone awards, Cosmetic 360 awards and C&T’s own R&D Awards. She is an active member of the Society of Cosmetic Chemists, the International Federation of Societies of Cosmetic Chemists and the Skin Microbiome Council.

We interviewed Rachel to understand her perspective on the biofilm modality entering the skin microbiome space, and to find out what inspires her in this area.

Are biofilms the ‘next big thing’ after the skin microbiome?

I think biofilms are an integral part of ‘the next big thing,’ emerging as a relevant extension of the skin microbiome and health overall. Science continues to uncover the cross talk and signalling between microbes and how this influences the host (and skin health); and biofilms are the collective medium through which these exchanges flow. So, it only seems logical that the biofilm, including not just microbes, but their surroundings could exert effects on those communications.

Experts have said the technology is not there yet to isolate and target specific microbes to improve skin health. Test methods such as 16S rRNA, for example, have their limitations and can yield skewed data. In addition, the microbiome itself is tenacious in returning to its initial state. Add to this the challenge of identifying what an “ideal” or healthy state skin is in the first place, and the mission seems nearly impossible.

What seems to be known, and what some researchers have targeted, is the overall ratio of entities within the microbiome. It appears the greater the heterogeneity of the microbiome community, the healthier the skin – so at the moment the real answer lies not in targeting the ‘bad guys’ but in understanding the entirety of the microbiome, including microbes, the biofilm and even the individual, his/her environment, etc.

Taking this further, I think the biofilm, encompassing the microbiome, is part of a greater holistic system of beauty, comprising the body, mind/emotions, surroundings, lifestyles, diet, etc. While an enormous amount of research has isolated biological targets upon which ingredients and hair/skin care products exert various efficacies, imagine what could be accomplished if we could better understand and capture the entirety of the human response to create product experiences that address the unwritten, between-the-lines facets of what makes us human.

We’re getting closer, with the incorporation of neuroscience and biometrics. I think we could also learn from individuals having unique sensory inputs for the benefit of all. Take those with heightened senses, for example, who have lost a primary sensory input but whose other senses have amplified as an adaptive response. Creating a product designed to engage their heightened senses could achieve a better product experience for others. Similarly, manipulating the biofilm in support of commensal species could achieve improved skin health for all. Easier said than done, of course, but both approaches would be important steps forward for beauty.


What specifically are your readers interested in regarding this topic?

Beauty, both physical and psychological, is heavily based on skin care and health. As such, skin health has always been a crucial topic of interest—even before the pandemic. It may have taken different forms (i.e., moisturization, anti-irritation, anti-aging, anti-sensitivity, etc.) but it’s especially relevant now, as we’re washing and sanitising skin (especially hands) to ensure systemic health in general.

Readers understand the biofilm and skin microbiome therein are components of skin health, so like many researchers, they are seeking to understand how these entities influence or protect skin. Microbe interactions, i.e., quorum sensing and/or mRNA communications, etc., could serve as potential targets for given topical chemistries that impart positive effects in skin. A better understanding of the biofilm’s role as a component of the microbiome affords opportunities, too; especially considering its heavy protein, lipid, polysaccharide, etc., content, familiar ingredients to a cosmetic formulator/researcher. These entities may, in fact, be easier to affect than living organisms. As such, you see prebiotic and postbiotic technologies introduced as approaches to skin care.


Who are the experts you would ask for a peer review?

I learned about the skin microbiome initially from Greg Hillebrand, Ph.D. (of Amway), and Larry Weiss, M.D. (of Symbiome), so they are my first go-to experts. I have spoken with several dermatologists as well, along with Katerina Steventon, Ph.D. (NBIC/Independent Consultant) and Cláudia Marques, Ph.D. (Binghamton University and Excelsior Biofilms, LLC), who presented on this subject at our Beauty Accelerate event in 2020. There also are several ingredient suppliers well-versed in this research. Known experts are emerging much like the field itself; in fact, I’ve just joined The Skin Microbiome Council, so this list will continue to expand.


What is it that the industry need to do first in terms of R&D and what are the key unanswered questions?

Specific to the biofilm and microbiome, like everything, it is difficult to know what you don’t know. Advancing technologies, assays, instruments, etc., to better capture the dynamics within the biofilm could elucidate some of these gaps in understanding; for example, what exactly a healthy skin microbiome looks like. Also, early work in industries such as personal care, while serving commercial interests, has uncovered nuggets of information from which others could build. As stated, this area is in its infancy but work is continually being generated and provides pieces of the larger puzzle.

Regarding cosmetics R&D in general, it’s been said that investment is the key to establish solid research that can lend itself to applications for industry. Many personal care companies have been heavily dedicated to this—budgeting resources, building facilities, aligning partnerships, etc – although like everything, the past year has been a major setback. Still, market analysts have projected increased spending in research, which will keep industry moving ahead. Also, research is not limited to the chemistry lab. It means getting closer to consumers as well, to understand how their needs have changed and to identify innovations that align with those needs.

In parallel with research, communication is crucial to understanding where there are potential synergies, gaps and opportunities. Finally, and R&D teams will love this: we need to find time. Everything in industry moves at a fast pace and pure scientific research comes at a premium. Rarely do scientists have the luxury to create and invent and plan and think and test – they have deadlines to meet. Perhaps this is where academia could partner with industry to advance the research.


Is influencing the skin microbiome a trend that’s here to stay?

I think the biofilm and skin microbiome are forever a part of consumers/consumer health and as such, it will always be relevant. It feels as though perhaps 10 or 12 years ago is when the discussion began but maybe the last eight years is when it gained momentum in the cosmetics R&D space. As stated, technology is still catching up with scientific interest, so it will continue to gain momentum as science uncovers ways to measure and detect it. Also, once a “healthy” biofilm/microbiome is defined, it will become a new target for product development


You operate internationally, do you believe the US is ahead of the curve in the skin microbiome R&D translation into consumer products?

I believe efforts are equal, globally, in facilitating the translation particularly of live probiotics, which are especially challenging, but also prebiotics and postbiotics into consumer products. One market report underlined L’Oréal S.A.’s (France) dominance in the “skin microbiome modulators” space, (1) but also named several other top players in this market, including: AOBiome (Massachusetts, USA), Azitra, Inc. (Connecticut, USA), Colgate-Palmolive Company (New York), Evelo Biosciences Inc. (Massachusetts, USA), Gallinée (London), Glowbiotics, Inc. (Arizone, USA), Johnson & Johnson Services, Inc. (New Jersey, USA), MatriSys Bioscience (California, USA), Quorum Innovations (Florida, USA), Revlon (New York), Siolta Therapeutics (California, USA), The Estée Lauder Companies, Inc. (New York), Tula Life Inc. (New York), Unilever (London) and Yakult Honsha Co. Ltd (Tokyo).

I think that research in the biofilm and skin microbiome, like most other fields, is closely connected in our digitized world, which has supported efforts around the world. However, the discussion with consumers about probiotic and microbiome-based products started with the idea of yogurt and “good bacteria,” which to my knowledge was embraced first in Europe. A quick Google search tells me the 19th century Russian scientist Ilya Ilyich Metchnikoff, a zoologist and microbiologist, was credited with this discovery. Apparently, he observed the longevity of rural Bulgarians and identified their incorporating soured milk (or yogurt) into their diets. It seems that European consumers were much earlier adopters to the notion of microbe-driven products for health benefits; foods in particular. Americans in general seemed less amenable to the idea that microbes could be good for you initially, as they were originally a target for elimination. In the late 1980s, though, the “hygiene hypothesis” emerged in the British Medical Journal, suggesting humans might be too clean for their own good. Through the internet, which became widely available around this time, this information disseminated quickly. More recently, efforts in clean and natural beauty and a focus on skin health have reinforced this approach and driven greater acceptance – as has a stronger consumer understanding of cosmetic ingredients.


As a consumer yourself, would you buy ‘skin microbiome friendly’ and/or the pioneering pro-biotic skincare products available on the market?

Yes, I would buy “skin microbiome-friendly” products; although from my perspective, I understand this could simply mean ‘gentler’ to skin. I feel as though my perception of this claim is skewed, as I have read perhaps more about this than an average consumer. I personally would delve into the ingredients list to see what might be in a product to determine if there are living entities. I also would read the description given in marketing material, searching for related patents on a given active to see what more I could learn. I do believe the claims in this space as far as prebiotic, probiotic, postbiotic, microbiome-friendly, etc., are not clearly defined, which gives creative license but may also confuse consumers. A recent article we published (2) actually proposes regulating these terms; it also underlines the complexity of doing so. Really, it is probably just a matter of time.


  1. Skin Microbiome Modulators Market to Reach $2.97 Billion by 2030 
  2. Microbiome Claims: Should Pre-, Pro- and Postbiotic Skin Care Be Regulated?


Rachel Grabenhofer, Managing Scientific Editor, Cosmetics & Toiletries