Skin microbiome: prebiotics and probiotics for healthy skin

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The skin microbiome is an invisible but essential protagonist: skin is not just a surface to cleanse, but a living ecosystem to protect. Problems such as persistent acne, excessive dryness, redness, and sensitivity often stem from an imbalance in this natural shield, not just from skin type.

Let's look at what it is, how it gets damaged, and how prebiotics, probiotics, and postbiotics can help restore its balance.

What is the skin microbiome?

It is the collection of microorganisms that live on the skin's surface. When the microbiome is healthy and diverse, the skin is protected, hydrated, and able to regenerate. When it loses diversity, pathogens take over and blemishes, redness, dryness, and hypersensitivity can appear.

It lives on the outermost layer of the epidermis and is one of the skin's defense systems, alongside the lipid barrier and the hydrolipid film. To understand how they work together, see the full overview in our guide on how the skin is structured and how it works.

Microbiota or microbiome: what's the difference?

The two terms are often used as synonyms, but they refer to different things. The microbiota is the community of microorganisms themselves—the bacteria, fungi, and viruses that live on the skin. The microbiome is the entirety of their genetic makeup and, by extension, the ecosystem they form with the skin environment.

In practice, the microbiota is who lives on the skin, while the microbiome is the community and all its genetic and functional material. “Microbiome” is now more commonly used in cosmetic terminology, but seeing “skin microbiota” on a label does not mean anything different.

What are the skin microbes?

The composition varies from one area to another because each region has different temperatures, humidity levels, and amounts of sebum. The most abundant groups are:

• Cutibacterium acnes (formerly Propionibacterium): predominant in areas rich in sebaceous glands, such as the face, back, and chest. It is a normal skin resident; only certain strains, under imbalanced conditions, are associated with acne.
• Staphylococcus epidermidis: one of the most widespread, it helps maintain an acidic pH and keep pathogens in check.
• Corynebacterium: prevalent in moist areas such as the armpits and skin folds.
• Malassezia: the most common yeast on the skin, involved in dandruff and seborrheic dermatitis of the face when it overgrows.

Its main functions

• Barrier effect: occupies available space and hinders colonization by pathogenic bacteria.
• Immune communication: helps the skin distinguish when to react and when to remain calm, helping prevent excessive responses.
• Maintaining pH: supports the skin's optimal acidity, which in itself inhibits the growth of pathogens. Learn more in our article on skin pH.

How it is damaged

When the balance between microorganisms is disrupted, it is called skin dysbiosis, a state of imbalance associated with various conditions: rosacea, acne, atopic dermatitis, and premature aging.

The most common causes:

• Aggressive cleansing: sulfate-based foaming cleansers and alkaline soaps remove natural lipids and disrupt the skin flora.
• Pollution and UV rays, which alter the microbial composition.
• Overuse of exfoliating acids and retinoids without adequate soothing support.
• Stress, antibiotics, and a low-fiber diet, which affect the gut microbiome and indirectly the skin microbiome.

One distinction worth keeping in mind: dysbiosis is associated with these conditions; it is not automatically their cause. For atopic dermatitis, rosacea, and moderate to severe acne, diagnosis and treatment remain the dermatologist's responsibility; a microbiome-friendly routine improves comfort and tolerance but does not replace treatment.

L'the gut-skin axis

The gut microbiome and the skin microbiome are not separate compartments. L'the gut modulates the body's immune response and inflammation levels, and the skin is affected: this is why periods of erratic eating, antibiotic treatment, or prolonged stress often lead to visible deterioration in complexion and blemishes.

In practical terms, this means two things. First, a diet rich in fiber and fermented foods also indirectly supports the skin. Second, no cosmetic product, however well formulated, can by itself compensate for an imbalance that originates elsewhere: topical skincare works best when everything else is in balance, too.

Prebiotics, probiotics, and postbiotics

They are not synonyms: they refer to different strategies. Understanding the difference is the first step toward making an informed choice.

Prebiotics

They are substances that selectively nourish beneficial microorganisms, helping them thrive at the expense of harmful ones. They are generally fibers and sugars: plant extracts, colloidal oatmeal, inulin.

They are particularly recommended for dry and sensitive skin that needs to strengthen its natural defenses.

Probiotics

Live bacteria are not used in cosmetics; instead, bacterial lysates or inactivated microorganisms are used. Even though they are not viable, these structures are recognized by the skin and activate positive immune responses, promoting the production of antimicrobial peptides.

They are recommended for reactive skin or acne-prone skin to reduce underlying inflammation.

Postbiotics

They are products of bacterial metabolism: fatty acids, enzymes, peptides, lactic acid. Their advantage is immediate availability — they provide the skin with the benefits of a healthy microbiome, hydration, and pH acidification, without having to wait for balance to be restored.

A review published in 2025 in Biomedicines explains why attention is shifting in this direction. Postbiotics are non-viable microbial cells or their metabolites: they pose fewer safety concerns than live microorganisms while still offering functional benefits. In a cosmetic product, which needs to remain stable for months inside a bottle, they make the most sense.

A helpful note when browsing the shelves: the terms “probiotic” and “microbiome friendly” have no regulatory definition in cosmetics. There is no standard certifying what they mean. What you can assess is the formula: no harsh surfactants, a pH compatible with the skin’s, and prebiotics or ferments listed in the INCI.

A 2026 review in the International Journal of Cosmetic Science clearly made the point: it’s not only targeted active ingredients that affect the microbiome. Surfactants, fatty components, preservatives, fragrances, vitamins and UV filters all interact with the skin ecosystem, and the pH of the finished product matters too. A microbiome-friendly cosmetic is built around the entire formula, not just one ingredient on the label.

Clinical evidence points in the same direction. In a 2023 randomized, double-blind study involving 14 people and using the split-face method (one product on one half of the face, the other product on the other half), products designed to support the microbiome increased bacterial diversity and reduced redness over three weeks compared with conventional skincare.

A routine that respects the microbiome

Affinity cleansing

The first step is to stop using highly foaming gels. Oil or milk cleansers are better: they cleanse without sterilizing.

Cleansing Gentle Oil removes impurities from pores through affinity cleansing while respecting the microbiome. It is made with hazelnut oil, carrot oil and grapeseed oil, with a fermented pomegranate enzyme extract that has a detoxifying effect.

Serums and treatments

You can choose formulas containing probiotic lysates or ferments, which support microbial balance.

Moderate exfoliation

It shouldn’t be eliminated, but adjusted by reducing mechanical scrubs and very high concentrations of acids.

Hydration

Creams containing prebiotic sugars such as inulin or fructooligosaccharides are useful: they nourish the skin barrier and protect it from external aggressors.

Sun protection

It completes the routine. Spot Defence 50 SPF is enriched with vitamin C and lactobacillus ferments, with bioactive metabolites — lactic acid, peptides, polysaccharides — that support the balance of the skin microbiota.

There’s one more reason not to skip it. In a 2023 pilot study, also published in the International Journal of Cosmetic Science, a sunscreen preserved components of the skin microbiome after a dose of UV radiation sufficient to redden the skin. The finding is in line with expectations: protecting your skin from the sun also protects its ecosystem.

If you'd prefer an in-person consultation before changing your cleanser, you can find LeLang products and expert advice at partner pharmacies across Italy.

Frequently asked questions about the skin microbiome

What is the skin microbiome?

It is the ecosystem formed by the microorganisms that live on the skin — bacteria, fungi, and viruses — together with their genetic material. It is not an unwanted guest: it contributes to the barrier function, maintains an acidic pH, and communicates with the skin's immune system, helping it distinguish between what deserves a response and what does not.

How can you restore the skin microbiome?

Rebalancing starts with removing things before adding anything. The quickest-impact step is to replace very foaming cleansers with gentle formulas at a compatible pH, and reduce the frequency of exfoliating acids and retinoids until the skin calms down. From there, support the ecosystem with prebiotics, ferments, and postbiotics, and protect it from UV rays. Typical timelines are 4-8 weeks: this is how long it takes for the microbial community to rebalance.

What is the best probiotic for skin?

There is no one strain that works for everyone, and it's worth noting that live bacteria are not used in cosmetics: instead, lysates or inactivated microorganisms are used, together with prebiotics and postbiotics. Lactobacillus ferments are among the most studied and widely used. Since the term “probiotic” is not regulated in cosmetics, the most reliable criterion is the overall formula: gentle surfactants, the right pH, and ferments listed in the INCI.

What are the skin's microbes?

The most prevalent are Cutibacterium acnes in oily areas, Staphylococcus epidermidis across much of the surface, Corynebacterium in moist areas, and the yeast Malassezia. The composition varies from person to person and, on the same person, from one area to another: the face hosts a different community from the forearm or scalp.

Does the scalp have a microbiome?

Yes, with its own distinct characteristics. The scalp is a warm, moist, sebum-rich environment where Cutibacterium and the yeast Malassezia predominate. When the latter overgrows, it is associated with dandruff and itching. The same logic applies here as to the face: shampoos that are too harsh or used too often worsen the imbalance instead of resolving it.

In conclusion

Taking care of the microbiome means working with your skin's biology rather than against it. It's also a shift in perspective: from “eliminating bacteria” to “supporting the right ones.”

If you're looking for stronger, less reactive skin in the long term, adding prebiotics, probiotics, and postbiotics to your routine is one of the most sensible strategies available today.

Sources for this article

01 Byrd A. L., Belkaid Y., Segre J. A., "The human skin microbiome", Nature Reviews Microbiology, vol. 16, no. 3, 2018, pp. 143-155. Review of the composition of the skin microbiota in different areas of the body, its variability, and its interaction with the immune system.
02 Salem I., Ramser A., Isham N., Ghannoum M. A., "The Gut Microbiome as a Major Regulator of the Gut-Skin Axis", Frontiers in Microbiology, vol. 9, article 1459, 2018. Review of the gut-skin axis and the modulation of the skin's immune response.
03 Regulation (EC) No. 1223/2009 on cosmetic products, Articles 2 and 20, and Regulation (EU) No. 655/2013 on common criteria for claims relating to cosmetic products: neither regulation defines the terms “probiotic” or “microbiome friendly”.
04 Prajapati S. K., Lekkala L., Yadav D., Jain S., Yadav H., "Microbiome and Postbiotics in Skin Health", Biomedicines, vol. 13, no. 4, 2025, article 791.
05 Santos Y. R., Andréo-Filho N., Lopes P. S., Leite-Silva V. R., "A review of skin microbiome and new challenges to cosmetic microbiome-friendly formulations", International Journal of Cosmetic Science, vol. 48, no. 4, 2026, pp. 780-797.
06 Randomized, double-blind, split-face study on 14 people, "Randomized comparative double-blind study assessing the difference between topically applied microbiome supporting skincare versus conventional skincare on the facial microbiome", International Journal of Cosmetic Science, 2023.
07 In vivo pilot study on 10 people, "Sunscreens can preserve human skin microbiome upon erythemal UV exposure", International Journal of Cosmetic Science, 2023.

On the website: how skin is made · skin pH · the skin barrier · seborrheic dermatitis on the face · understanding acne