Skin Microbiome: Why It's a Breakthrough

The skin microbiome is one of the most fascinating discoveries in modern science, completely reshaping the way we see our bodies and skin health. Just 25 years ago, Nobel laureate Joshua Lederberg invented the term “microbiome.” Today, we know our bodies are hosts to billions of microorganisms, and their collective genome — the microbiome — is essential for life, immunity, and wellbeing.

Both terms are now common in discussions about gut health or advanced skincare, but each plays a unique role in your overall well-being.

Picture placing a brand-new computer next to your old one. While they may look identical, the old computer contains data — apps, contacts, photos — that define how it works for you. The new computer is technically the same hardware, but empty. This analogy reflects the relationship between your body’s microbiota and microbiome:

From the earliest moments of life, we’re already in contact with the microbiome. Our bodies partner with these microbes for symbiotic benefits: they provide protection, teach our immune cells, and even help us adapt to the environment. In a poetic sense, each person is a planet providing a home for fertile microbial life, while we ourselves are just a tiny part of Earth’s vast microbiome.

There’s no universal definition of a “normal” skin microbiome. 

Like Morticia Addams said, “Normal is an illusion.” What lives happily on one person may cause problems for another. Each skin’s ecosystem is unique, shaped by family, environment, and daily habits.

The bacterial component of the skin microbiome is made up of four main bacterial groups: Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes. Important players include Staphylococcus (which has both beneficial and harmful strains), Cutibacterium acnes (not just acne-causing — beneficial for healthy skin), lactic acid bacteria like *Lactobacillus*, and many others. Fortunately, among the millions of bacteria around us, only about 200 types are considered pathogenic — most actually contribute to skin health.

Even so-called "bad" bacteria only cause problems when they overgrow; skin microbiome health depends on a delicate balance, not the mere presence of one species or another. Fungi and viruses on the skin are less understood, but scientists believe the virome — the community of viruses on the skin — is mainly protective. Bacteriophages, the most common viruses on our skin, help control bacterial populations and may prevent infections. Other viruses may even protect against UV-induced skin cancer, a new frontier in microbiome research. 

While less is known about the roles of fungi and viruses, it's clear that phages can help defend the skin from infections, and fungi support skin protection and overall balance. Many skin fungi collaborate with bacteria to produce protective substances unique to healthy skin. However, under certain conditions, bacteria, fungi, and possibly viruses can overgrow, forming resistant biofilms that lead to chronic skin problems and make the skin harder to treat.

Biofilm is a recently described phenomenon in which microorganisms develop communication and cooperate to form remarkably stable communities. This process, known as quorum sensing, relies on biochemical messaging between organisms. For microorganisms, biofilm formation represents an evolutionary advantage, as it allows the creation of colonies that can protect themselves from external threats, including elimination efforts.

Unfortunately, this adaptation is often detrimental to humans, as biofilms can result in chronic and treatment-resistant infections. Chronic acne, for example, is now recognised as a biofilm-associated skin condition. Improved understanding of the role of biofilms in chronic skin conditions has led to changes in treatment protocols, including a reduced reliance on antibiotics in dermatology and new strategies that target and disrupt biofilm communities for improved therapeutic outcomes.

Microbiome-friendly means products that don’t disrupt skin flora. They avoid changing pH, disinfecting, or sterilising skin. Keeping your microbial ecosystem happy means healthier, slower-aging, and better-protected skin.

“Microbiome-friendly” is used for products that are neutral and do not disturb the skin’s natural microbial balance — they are essentially inert or gentle, minimising disruption. It’s misleading to describe skincare that actively restores or corrects microbiome imbalances (such as targeted acne care) as “microbiome-friendly,” because these formulations are designed to interact with the ecosystem, not simply protect it.

Rather than simply using the label “microbiome-friendly,” it is better to speak about microbiome-addressing skincare that actively targets microbial imbalances and aims to restore harmony. Microbiome scientists recently introduced the concept of microbiome support — skincare designed to promote resilience and balance, especially when the microbiome has been disrupted.

Supporting or restoring a healthy microbiome must be nuanced:

New generation ingredients that actively support microbiome health fall under the “-biotics” umbrella:

These ingredients allow for truly microbiome-supportive and microbiome-addressing skincare, going beyond neutrality to actively encourage recovery, resilience, and optimal skin health — provided they’re chosen for each skin’s unique environment and needs. 

However, topical products with probiotics are still limited to personal care brands because they contain high amounts of live bacteria, making it hard to meet old fashioned testing rules for microbial content. Most skincare brands now use postbiotics in their formulations but often call them probiotics — this has become a common practice. Technically, it’s not entirely wrong, since terms like postbiotics, paraprobiotics, non-viable probiotics, inactivated probiotics, tyndallized probiotics, or ghost probiotics are all used for products containing non-living microorganisms. 

However, at Meder, we believe the best practice is to be precise: we specify when probiotics are inactivated, and we include this information educating skin professionals. 

We are ecosystems, not just individuals. By respecting the microbiome, we ensure healthy, radiant, and resilient skin — and contribute to a healthier planet for all.

Try the Meder Quiz to choose a personalised, microbiome-supporting skincare routine.