Skin-friendly bacteria: The role of microbiota in modern cosmetics

In recent years, the concept of the microbiome has moved from scientific curiosity to a key focus in skincare. Terms like “microbiome-friendly” and “made with probiotics” have gained popularity, reflecting a trend towards enhancing the skin’s natural microbial ecosystem. Probiotics, prebiotics, and postbiotics are increasingly being incorporated into cosmetic formulations, aiming to nourish and balance the skin’s delicate flora. This surge in interest is driven by increased research into the skin microbiota, which has uncovered the role it plays in maintaining healthy skin.

While the first probiotic cosmetics emerged years ago, the industry has since advanced, with new discoveries showing the impact the skin microbiome has on dermatological health. This evolving understanding has led to a shift in approach, recognising that certain bacteria are not just harmless but can actively benefit the skin.

Unlocking the power of skin microbiota
The human skin hosts a diverse community of microorganisms, including bacteria, fungi, moulds, yeasts, viruses, and parasites. These microorganisms play a crucial role in maintaining the skin’s health, supporting immune function, and preventing harmful pathogens from colonising. The term microbiota refers to the population of microorganisms that naturally live in a specific area of the body, while the microbiome refers to the collective genetic material of these microorganisms, forming a complex network of interactions with our cells.

The composition of the human microbiota is dynamic and influenced by factors such as geography, external conditions, diet, and age. Studies have shown that an imbalance in microbiota, known as dysbiosis, can contribute to various skin problems, including acne, rosacea, and atopic dermatitis. In contrast, maintaining a balanced microbiota, or eubiosis, can improve skin hydration and elasticity. This understanding has driven the rise of microbiome-friendly skincare, with products designed to nurture beneficial skin bacteria.

Probiotics, Prebiotics, and Postbiotics in skincare
In nutrition, probiotics, prebiotics, and postbiotics support microbial balance by acting internally through ingestion and colonization. In skincare, they may help maintain the skin microbiota externally by creating a favourable environment for beneficial microorganisms. Here’s how they are used in skincare.

• Probiotics: According to the World Health Organisation, probiotics are “live organisms which, when administered in adequate amounts, confer a health benefit to the host” – typically by improving or restoring the gut microbiota when taken orally. In topical application, these bacteria do not “colonize” the skin but can positively influence the skin microbiota by supporting the microorganisms already present, supporting the skin balance. However, their viability in formulations remains a challenge, as formulators must balance protecting products from harmful bacteria while keeping beneficial ones alive despite preservatives and environmental exposure. Maintaining live bacteria over time is difficult, and while there are methods to extend their lifespan, they typically have a shorter shelf life in packaging.
• Prebiotics: These are not microorganisms, but organic substances that provide a favourable environment for beneficial microflora. Prebiotics include fibres and sugars such as inulin, glycosaminoglycans, beta-glucans, and oligosaccharides, usually derived from plant sources or biotechnology. These ingredients serve as a source of nutrients for beneficial bacteria, helping them thrive and maintain balance. Prebiotics are already well-known and used in cosmetics (e.g.: as humectants), and unlike live microorganisms, prebiotics are easy to incorporate into formulations – although it is always necessary to demonstrate their ‘prebiotic’ function for the skin (i.e., promoting the growth and survival of beneficial microorganisms already present in the skin microbiota)
• Postbiotics: These are substances derived from microorganisms or their metabolism, such as peptides or organic acids obtained through fermentation. Postbiotics offer anti-inflammatory, moisturising, and protective benefits. This area opens many possibilities because by changing the microorganism or the fermentation substrate, a wide range of different substances can be produced, each with its own chemical characteristics and cosmetic properties.

The science behind “microbiome-friendly” cosmetics
The cosmetics industry has increasingly turned to biotechnology to harness ingredients that support the microbiota. Fermentation, for instance, has become a key process in creating skincare components, driven by the need for greater sustainability. It has made many plant-based alternatives to synthetic derivatives available. In fact, today substances from small amino acids to large sugar polymers can be obtained through the fermentation of plants using microorganisms.

In this context, certified natural cosmetics have become a preferred choice for conscious consumers. The NATRUE standard, with its strict criteria excluding synthetic substances from formulations and only permitting natural, derived natural or nature-identical substances, supports fermentation methods. NATRUE-certified products often contain lactobacilli, soluble prebiotic fibres such as inulin (from chicory), polysaccharides (from fruits and algae, etc.), and a variety of plant extracts obtained via fermentation. If you want to explore these options, feel free to check NATRUE’s database.

Regulatory considerations and consumer transparency
Cosmetics labelled “with probiotics” or claiming to “restore the skin flora balance” are gaining attention, supported by scientific studies on the skin microbiome or highlighting ingredients like lactobacilli. We need to keep in mind that, while the presence of lactobacilli in a cream may help balance the skin microbiome, improve hydration, enhance the skin’s barrier function, the term “probiotic cosmetics” is not regulated. Brands making such claims must substantiate them with clinical studies, as the absence of guidelines for “probiotic cosmetics” leaves room for misleading marketing.

Regulation (EU) No. 655/2013 recommends that claims for cosmetic products shall be supported by adequate and verifiable evidence, ensuring that consumers receive accurate and well-founded information. Certifications like NATRUE offer an additional assurance that products meet stringent natural and sustainable criteria.

The future of microbiome-focused skin care
As consumers become more aware of the importance of the skin microbiota, demand for microbiome-friendly cosmetics is expected to grow. Biotechnology and fermentation processes will be key in crafting the next generation of sustainable, effective skincare solutions. With ongoing research, we can expect more advanced, scientifically-backed formulations that truly nurture and balance the skin.

Article written by Paula Gómez de Tejada, NATRUE Global Communications and Public Relations Manager, and Diana Malcangi, NATRUE Scientific and Regulatory Consultant. It was originally published on Bio Eco Actual (available in Spanish and Catalan)