Skin microbiome exploration: looking back at five years of The Secret Life of Skin project.  

Why did we start The Secret Life of Skin platform? 

Back in early 2019, The Secret Life of Skin launched to provide an engaging central hub of information around a then relatively new, and lesser known, research area – the skin microbiome. Funded by dsm-firmenich (then DSM), we sought to be one of the earliest to fully capture the many complex possibilities that a greater understanding the skin microbiome and its many interactions with the skin offered for a myriad of skincare applications. With the intention to make this knowledge and secret side of skin health & beauty accessible we decided to call it “The Secret Life of Skin”. 

We sought to open up the skin microbiome to audiences with different levels of understanding, from those who knew nothing about it to experts looking to stay up to date with the latest findings. To do this, we knew we had to create a space that harmonizes the technical with the creative – in order to inspire around the skin microbiome and its future potential to revolutionize modern skincare.  

Where are we now? 

We now sit on five years of expert content that represents a truly holistic exploration of the skin microbiome and related topics – both here and on our Instagram channel. We like to think we have become a ‘go-to’ platform– a one-stop shop for answering your questions on the skin microbiome and opening minds to the myriad of possibilities. Our blog content is underpinned by robust scientific insight, but with a consumer flair and a focus on ‘real-world’ applications that benefit both the scientific and skincare R&D community but also the informed and solution-seeking consumer. Instagram has been an important channel to connect consumers to these ideas and to help us understand the trends and topics that have been drawing consumers to take an interest in the skin microbiome. 

The world is now much more alive to the potentials of protecting, and even harnessing, the skin microbiome for better skin health. It is now time to move from education to action – over time, we will be moving our key content over to dsm-firmenich, as part of its journey into microbiome modulated beauty, hygiene and oral care. We regularly propose formulations (skin, sun hair), solutions and webinars around the topic of microbiome. Stay tuned! 

Our readers’ most popular skin microbiome topics 

We are thrilled to have brought together such an engaged, diverse group – from research scientists and skincare R&D professionals to consumers with particular skin conditions and/or interests in innovative skincare. A huge thank you to our loyal Secret Life of Skin community who have come back time and again to join us on this learning journey, especially for you, here is a throwback to the top five articles you’ve found most interesting over the years: 

1. E-Coli

The first thing many of us would think to do in the presence of ‘E-Coli’ is wash out hands to stop the spread of infection! Yet its presence in the gut and skin goes beyond the misleading dichotomy of good and bad bacteria. Escherichia coli (E. coli) is a bacteria recognized for its resourcefulness and adaptability, capable of producing biofilms under stress and altering its genetic makeup for enhanced virulence. In this article The Secret Life of Skin examines how E. coli achieved its celebrity status, the processes it goes through in a day, and how it impacts the skin microbiome. 

Read the full article: Introducing Escherichia coli (E. coli) 

2. Gut-skin axis 

This article explores the intimate relationship between the gut and the skin – in particular the link between gastrointestinal health and skin homeostasis. In particular, intestinal dysbiosis (microbial imbalance) can negatively impact the skin microbiome and its basic functions, contributing to skin disorders like acne, psoriasis, atopic dermatitis (eczema) and rosacea. Probiotic supplements however do show promise in preventing and managing skin disorders. Probiotics can, for example, suppress Propionibacterium acnes (P. acnes), the bacteria responsible for acne breakouts. 

Read the full article: The Gut-skin axis 

3. Prokaryotes 

The popularity of this article really took the team here by surprise – who knew the sexual lives of microbes would hold such fascination! Here we explore the methods of reproduction of prokaryotes – single-celled organisms that lack a membrane-bound nucleus, i.e. bacteria and archaea. While they usually reproduce asexually, sexuality brings genetic recombination and variability that allows them to adapt to changing environmental conditions. The four key mechanisms are mutation, transformation, conjugation, and transduction – through this, prokaryotes have become the genetically most diverse and successful form of life on this planet. Good for you, prokaryoktes! 

Read the full article: The Sexual Life of Prokaryotes: Bacteria & Archaea 

4. Glycolic acid 

Glycolic acid, a small alpha hydroxy acid, has gained popularity in skincare, due to its exfoliating properties. Here we explore its impact on the skin microbiome – for good and bad. Glycolic acid is effective in treating acne by unclogging pores, reducing skin marks, and killing acne-causing bacteria (most effectively at a pH of 3). It also helps reduce inflammation and repair the skin barrier for those with atopic dermatitis. However, it can also disrupt the skin microbiome, affecting both beneficial and pathogenic bacteria. Its non-specific action necessitates careful use, as overuse may lead to skin sensitivity and affect collagen production. Despite these concerns, when used in moderation, glycolic acid can improve skin complexion and assist in maintaining skin health.  

Read the full article: Glycolic acid for the treatment of Acne and Atopic Dermatitis 

5. Prebiotics, Probiotics and Postbiotics 

There is much hype around these three terms but not everyone understands what they actually do or their different roles in relation to the microbiome. Formulating with Pre, Pro and Postbiotics can help gently rebalance our complex skin microbiome by selectively feeding key microbes (Prebiotics), by providing key beneficial and alive microbes (Probiotics) and by delivering the materials microbes produce, which stabilizes the skin microbiome (Postbiotics). So long as the industry clearly communicates with consumers, avoids loose use of terms like ‘probiotic’, and recognizes the importance of strain specificity and dose, the next generation of cosmetics are all set to make a huge impact on skin health. 

Read the full article: Formulating skin care products with Prebiotics, Probiotics and Postbiotics 

A spotlight on our top contributors 

It would also have not been possible to create such a rich knowledge base without such a great number of experts over the years, from researchers to dermatologists and skincare entrepreneurs, who have contributed their knowledge to this blog.  

Today we shine a new spotlight on our two most active contributors over the past five years of The Secret Life of Skin – Dr Barbara Brockway and Dr Markus Egert – looking back at our favorite articles. We also reflected with Dr Mathias Gempeler and Dr Martin Pagac from dsm-firmenich, who have been central to this project over the years, on what they have found most interesting during the Secret Life of Skin project, and their top picks. 

Dr. Barbara Brockway: top picks 

One of most prolific writers for The Secret Life of Skin, Dr. Brockway has contributed sixteen articles over the years, with many of these being our most read of all time. Across her 30+ year transatlantic career across both academia and natural cosmetic actives, she has shared our passion for applying the latest scientific discoveries to personal care. She’s covered a range of fascinating topics from skin conditions like acne and rosacea and their links to research activity in the skin microbiome to the potential of developing a vaccine to protect against skin conditions like acne and atopic dermatitis. As a Forensic Cosmetic Scientist, she is also our perfect choice to discuss microbial forensics. Here are our team’s favourite articles from Dr. Barbara: 

1. Is the microbiome-selfie set to revolutionize human health? 

What can a microbiome-selfie tell us about human health? Dr. Brockway dives into the groundbreaking advances in mapping the human microbiome, particularly the skin microbiome. As we age, our skin microbiota becomes increasingly diverse, forming complex communities that contribute to our health. The use of culture-independent techniques like next-generation sequencing has been pivotal in revealing the extensive diversity of our skin microbiota, encompassing over 350 different microbial species. This detailed mapping of microbial communities has shifted the narrative from “good and bad” microbes to a more nuanced understanding of their interdependent roles in maintaining skin health. The uniqueness of each individual’s microbiome, influenced by numerous factors, is now also seen as a valuable tool in forensic science, an expanding frontier for the beauty industry to explore. 

2. Introducing Lactobacillus part 1: Taxonomy, antimicrobials, and immunity  

This article shines a spotlight on Lactobacillus bacteria, a mixed group of lactic acid-producing bacteria that are of special interest as antimicrobials in skincare and cosmetic applications thanks to the bacteriocins they produce. An excellent example of the dynamic nature of microbial classification, in 2019, the Lactobacilleae family was reclassified from 250 specifies to 25. As cell surface components, LAB can prevent pathogen infection and even modulate the host immune system. While living at only low levels on skin, they overwhelmingly dominate healthy human vaginal microbiotas, maintaining the pH of reproductive age women at around pH 3.5-4.5. By creating a local acidic environment, they product biofilms, provide nutrients and release bacteriocins that help prevent potential pathogens from becoming established.  

3. Acne: Conventional treatments and cosmetic ingredients  

Here Dr Brockway examines the multifaceted nature of acne, from its causes, such as C. acnes proliferation and hormonal influences, to various treatment approaches including conventional treatments like benzoyl peroxide, retinoids, and antibiotics, as well as cosmetic approaches such as natural actives and the role of nutrition in skin health. When the potential effectiveness and side effects of these different options, it’s clear that acne treatments must address multiple causes and that the microbiome’s balance is crucial for effective acne management. 

4. Microbial forensics  

Did you know that every time we touch a surface – our phone, coffee mugs, the office door – we leave behind skin microbes, otherwise known as the ‘touch microbiome’? Each of us has our own distinct microbial signature – and though early days, its use in forensics is an exciting area of work. Already it’s possible to identify a person’s gender, how they live, their species of pet, the medicine they take and more from the trace microorganisms left on surfaces. The potential for creating databases of touch microbiomes, akin to fingerprint databases could not only help police find offenders but could provide useful information to dermatologists and cosmetic scientists looking for microbiome elements to target to help skin achieve its optimum health. 

5. Vaccines to combat skin diseases associated with the skin microbiome 

Could we one day harness the immense power of vaccines to protect us from developing hard-to-retreat skin diseases? Dr Brockway reviews the different vaccines currently being researched, including for Staphylococcus aureus infections, which could offer protection against atopic dermatitis (eczema), cellulitis, and impetigo. Research is also underway to explore vaccines for acne and skin allergies like contact dermatitis, indeed potentially as early 2027 for acne. When developing vaccines like this, researchers need to be alive to the delicate balance between the skin and its microbiota and be complementary to existing adaptive immunity. Safety remains a paramount concern in vaccine development. 

Dr. Markus Egert: top picks 

Our other most prolific writer for The Secret Life of Skin, Dr. Markus Egert has also contributed sixteen articles over the years, with several again coming into our list of top articles of all time. Dr Markus Egert is a professor for Microbiology & Hygiene at Furtwangen University and a founding member of the Institute of Precision Medicine. His main research interests are the human microbiome (intestinal tract, skin) and the microbiome of the built environment of humans. He’s certainly been our go-to for our explorations of the way our skin microbiome can be affected by our Western lifestyles. It’s again very hard to choose which of these articles got our synapses firing most, but these are the top picks from the team: 

1. The microbial mystery of foot odor 

Despite significant advancements in human microbiome research, the foot microbiome and its relation to foot odor remain underexplored compared to body (axillary) odor formation, here Dr Egert reviews what we do know to date. The leading cause of foot odor is microbial degradation of dead skin cells and proteins, regulated by foot wetness. Staphylococcus, Corynebacterium, and Acinetobacter as dominant bacteria on the feet, with staphylococci being abundant on the soles. The cheesy odor of feet is primarily due to isovaleric acid produced by staphylococci from amino acids like L-leucine. Though staphylococci are present all over the bodily microbiome, thankfully only the feet provide the distinct warm and wet conditions for the odor to take hold! In 2006, Bart Knols notably won the Ig Noble Prize for proving that malaria mosquito Anopheles gambiae are equally attracted to limburger cheese and human feet smell – it’s all about the bacteria! 

2. Scalp microbiome: Where research needs to go next. 

Like soil for plant growth, a healthy scalp is a prerequisite for healthy hair – with ‘crown care’ a new beauty trend. Yet, much to our dismay, functional human scalp microbiome research (looking at not just which microbiota are there, but what are they doing) is still rare, two years on from Dr. Egert’s first blog on the topic. Of the five recent studies, the most notable is a landmark study from Saxena et al. showing that coconut oil treatment increased the relative abundance of Cutibacterium acnes and Malassezia globosa in samples from dandruff probands, accompanied by a relative decrease in funghal pathogenesis pathways and increase in health-scalp-related bacterial pathways, such as biotin metabolism. Read the full article for Dr Egert’s review of the other four.  

3. Time for re-wilding? Western lifestyle and the human skin microbiota 

Did you know that industrialization and urbanization as well as specific ‘western lifestyle’ characteristics such as individualisation, urban living, processed foods and increase use of antibiotics and disinfectants, are contributing to a decrease in microbiota diversity? Studies have even shown that living closer to nature, as in rural Karelia, Russia, is associated with lower rates of allergies and better skin health, attributed to the presence of beneficial bacteria like Acinetobacter. In contrast, urbanized areas have higher rates of eczema and a decrease in beneficial skin bacteria. Further research into these environmental effects is needed to build sustainable, long-term strategies for the preservation of microbes currently vanishing from the human microbiome. It is not yet clear whether a re-introduction of lost microbes would be beneficial or unhealthy, such is the complexity of the subject. 

4. Discrimination and dysbiosis: How do social inequalities influence the skin microbiome? 

Sadly, socioeconomic status has been found to significantly impact human health, including our microbiome. Our gut microbiome can be impacted by our diet, how long we are breast-fed, stress, alcohol, cigarettes, access to safe outdoor spaces, pollutant and pathogen exposure and circadian dysregulation (i.e. due to shift work). In the worst cases, this can lead to acute and/or chronic disease symptoms and a weakened immune system. Research has also looked at how losing opportunity for the exchange of beneficial bacteria between mothers and their babies can also impact our skin microbiome composition – such as vaginal birth, breastfeeding and regular skin-to-skin contact – with key differentiators between lower and higher economic populations. The accommodation of longer periods of maternity leave can be beneficial here. Interdisciplinary collaboration between microbiome scientists, epidemiologists, and social scientist could help address these links.  

5. Are pets probiotic? 

Here Dr Egert explores the microbial exchange – or shared microbiome – between humans and our pets. He highlights how exposure to diverse microbes from pets during childhood can actually lower rates of asthma and allergies. This is attributed to the beneficial impact of microbial diversity on the immune system. Despite the risks of zoonoses (infectious diseases spread from animal to human and vice versa), some scientists have suggested that pets could act as a form of microbiome-based therapy, especially for those children in urban environments with limited exposure to natural microbiota. Should you kiss your dog twice a day instead of eating probiotic dairy products? We’d say balance the benefits (immune-stimulating microbes) with the risks (risk of zoonotic infection) with good overall hygiene practices (proper hand hygiene, no licking of the face or open wounds and regular check-ups with the vet. 

Reflecting on The Secret Life of Skin project over the years, we also spoke to two key people to the project – Dr Mathias Gempeler and Dr Martin Pagac from dsm-firmenich, what have been your highlights on this journey from limited understanding and awareness to microbiome modulated beauty, hygiene and oral care product development?  

Looking back with Dr. Martin Pagac 

It has been fascinating to be part of a generation of scientists that can contribute to a better understanding of the role of the skin microbiome on human and animal health, as well as experience daily the growth of knowledge around this exciting theme.  

It is satisfying to see that in a relatively short period of time the skin microflora was placed in another light: For decades, skin-resident microbes were considered as disease-causing matter that is best to be removed with harsh cleaning agents. Recently, they are now seen as important protectors of skin health even with potential positive impact on distant organs. 

While it is certainly complex enough for experts in the field to keep up with new ground-breaking findings in the skin microbiome field, it was challenging, yet extremely rewarding, to share this knowledge with the TSLOS community. 

Personally, my favorite articles related to communication of novel groundbreaking findings that aimed to positively change the perception of skin microbes, are the following: 

1. Is a high microbial diversity beneficial for skin and scalp health?  

Contrary to the gut microbiome system, this statement cannot easily be applied to skin. This article shows that the function of the microbiome depends on its location and highlights the potential to use microbiome-targeting strategies to treat microbiome-associated skin diseases. 

2. Malassezia in cosmetic research  

It was an honor to have the opportunity to speak with Dr. Tom Dawson, one of the world-leading experts in the skin mycobiome field (the fungal component of the microbiome). The skin microbiome not only consists of bacteria, but also of a substantial number of fungi, such as several Malassezia species. While Malassezia is associated with dandruff, and its removal clearly reduces symptoms of dandruff, he now believes that Malassezia actually has an important function as a protector of our skin from harmful extrinsic factors, not limited to pathogenic invaders. 

3. Using skin-resident microbes as on-site biomanufacturing platforms 

Instead of removing microbes from skin, as was considered previously an important hygienic action, the opportunities are immense for harnessing the power of skin-resident microbes and turning them into little bio-factories for the production of beneficial compounds on skin and improve or restore human health, not limited to skin. 

4. How do facial skin microbiomes change after menopause? 
The facial skin microbial diversity increases in postmenopausal women, when compared to premenopausal women. Furthermore, the abundance of lipophilic Cutibacterium genus decreases on postmenopausal skin. These two features are associated with skin disorders experienced by postmenopausal women. Can a microbiome-targeting approach, aiming to reduce microbial diversity and increase Cutibacterium presence improve facial skin health of postmenopausal women? 

Reminiscing with Dr. Mathias Gempeler 

What I found most fascinating about The Secret Life of Skin project was that we had the opportunity to start practically from scratch and write about topics that we thought would be of interest to a wider audience. Another exciting aspect was finding suitable authors. We were lucky that microbiome is a relatively new technology in the field of skin care and that the researchers in this field were willing to share their knowledge. There was a strong consensus that sharing knowledge about skin microbiota will help the acceptance of this still young field of research.  I was asked again which were the most interesting articles for me, this question is impossible to answer as every single article contributed to the success of the idea of The Secret life of skin. If one article has changed my behavior, then it was the article about the kitchen sponge, I don’t need that anymore. When I look back over the years, I see a clear change in the skin microbiome. The skin microbiome will remain a topic in the field of skin care, especially when it comes to understanding the interactions of the microbiome with the exposome and with the skin. The microbiome is part of a larger system and not an isolated layer on the surface of the skin. 


In conclusion, The Secret Life of Skin project, started back in 2019, has contributed to the growth in collective understanding of the skin microbiome, revealing its intricate connection with overall skin health and the potential for innovative skincare applications. Over the past five years, our platform has evolved into a comprehensive resource, combining scientific insights with consumer-friendly information, thereby bridging the gap between complex microbiological research and practical skincare applications, from the website to consumers’ mobile screens on Instagram. 

The project’s exploration of diverse topics, ranging from the impact of E. coli on the skin microbiome to the interplay between gut health and skin conditions, reflects our commitment to providing holistic and up-to-date information. The popularity of articles on prokaryotes, glycolic acid, and the roles of prebiotics, probiotics, and postbiotics in skin health underlines the growth in public interest in understanding and leveraging the skin microbiome for better skincare. 

Contributions from esteemed experts like Dr. Barbara Brockway and Dr. Markus Egert have enriched the platform, offering insights into microbial forensics, the potential of vaccines targeting skin diseases, and the intriguing relationship between lifestyle factors and skin microbiota diversity. Their research and ability to eloquently translate the complex interdependencies within our microbiome, has been incredibly valuable and underscores the importance of continued exploration in this field. 

As The Secret Life of Skin project transitions its content to dsm-firmenich, it marks a new phase in the journey towards microbiome-modulated beauty and healthcare products. t. This shift mirrors an industry-wide evolution, transitioning from an educational focus to a heightened demand for implementing microbiome research directly into product development 

The journey of The Secret Life of Skin project exemplifies the dynamic and evolving nature of skincare science. It underscores the importance of understanding the skin microbiome’s role in health and beauty, and the potential it holds for future innovations. As we look ahead, it’s clear that the insights gained from this project will continue to influence and shape the future of skincare, highlighting the pivotal role of the skin microbiome in promoting health, well-being, and beauty. 

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