The skin microbiome: your skin's new (forgotten) ally

Key takeaways

• The skin hosts micro-organisms that help protect it and keep its pH stable (around 5).
• Very foaming cleansers, hot water and repeated washing disrupt this balance.
• Korean ferments and postbiotics mainly aim to keep the skin calm and stable.

We talk a lot about the gut microbiome, almost never about its skin equivalent. Yet, the skin is home to millions of bacteria, fungi, and viruses that work silently to protect it. When this balance is disrupted, the skin becomes more reactive, more prone to redness, blemishes, and dehydration—often without us understanding why.

What exactly is the skin microbiome?

It is the collection of microorganisms that live on the surface of the skin, in balance with it. This microbiome helps regulate pH, protects against unwanted bacteria, and constantly communicates with the skin barrier. Skin with a balanced microbiome is generally more tolerant, more stable, and reacts less to changes in seasons or products.

Why it determines the health of the barrier

The microbiome and the skin barrier work as a team. An unbalanced microbiome (known as dysbiosis) promotes low-grade inflammation, which in turn weakens the hydrolipidic film. It is a self-perpetuating cycle: the weaker the barrier, the more the microbiome becomes unbalanced, and vice versa.

The habits that destroy it without us realizing it

Some very common habits disrupt the microbiome much more than we think: highly foaming cleansers and traditional soap, which raise the skin's pH far from its natural value (around 5), excessive cleansing or cleansing with water that is too hot, the systematic use of makeup remover wipes, and the proliferation of products containing denatured alcohol or strong fragrances.

Creating a "microbiome-friendly" routine

The idea is not to add specific products at all costs, but to remove what causes irritation: a cleanser with a pH close to that of the skin, lukewarm water, and regular hydration that maintains an environment favorable to good bacteria. The simplicity of the routine is itself a strategy for preserving the microbiome: fewer different ingredients, less risk of destabilizing it.

Probiotics and postbiotics in Korean cosmetics

Korean research has long been interested in ferments and postbiotics (extracts of inactivated beneficial bacteria) in essences and lotions. These ingredients do not directly "feed" the microbiome in the strict sense, but create a more stable, less inflammatory skin environment, which indirectly benefits the overall bacterial balance.

Which product to choose

• Probiotic essence: the Black Rice Probiotics Barrier Essence by Haruharu Wonder.
• Soothing ampoule, with centella and probiotics: the Madagascar Centella Probio-Cica Intensive Ampoule by Skin1004.
• Bifida cream, for the evening: the Bifida Biome Aqua Barrier Cream by Manyo.

Taking care of your microbiome, therefore, is not about adding an extra step to your routine. It is often about removing one, and letting the skin regain on its own a function it knows very well how to perform.

Read also: Damaged skin barrier: how to repair it · Double cleansing: essential ritual or unnecessary step?

Sources

• Byrd AL, Belkaid Y, Segre JA. The human skin microbiome. Nat Rev Microbiol, 2018. doi:10.1038/nrmicro.2017.157
• Grice EA, Segre JA. The skin microbiome. Nat Rev Microbiol, 2011. doi:10.1038/nrmicro2537
• Lambers H et al. Natural skin surface pH is on average below 5, which is beneficial for its resident flora. Int J Cosmet Sci, 2006. doi:10.1111/j.1467-2494.2006.00344.x