Understanding Postbiotics: What exactly are they?
We often hear about probiotics and prebiotics in skin care, but a new generation of compounds is increasingly intriguing scientists and formulators: postbiotics. Neither alive nor simply nourishing, they are active by-products of the microbial world, capable of strengthening the skin barrier, soothing inflammation, and slowing down the signs of aging. With their use exploding in dermatology and cosmetics, let's find out why these inert components could well become the real invisible heroes of your beauty routine.
Scientific definition of postbiotics
Postbiotics are defined as preparations of non-living microorganisms and/or their components (cell fragments, enzymes) that offer a proven health benefit to the host. Unlike probiotics, they are not alive but retain biological efficacy.
These substances result from the fermentation of prebiotics by microorganisms—mainly beneficial bacteria—and include:
- Organic acids
- Antimicrobial peptides
- Enzymes
- Polysaccharides
- Membrane proteins
The role of skin microbiota
Visit skin microbiota refers to all microorganisms present on the skin's surface. It contributes to immune defense, hydration, and healing. When imbalanced (due to pollution, stress, treatments), the skin becomes more sensitive and prone to various conditions: acne, dermatitis, premature aging.
Postbiotics help restore a balanced bacterial environment, which is essential for healthy skin.
How do they differ from prebiotics and probiotics?
Postbiotics do not replace probiotics or prebiotics, but complement their action. The prebiotics serve as substrates for good bacteria, the probiotics are live bacteria that directly strengthen the microbiota, while postbiotics are their fermentation products: active and targeted residues, often easier to formulate and more rapidly effective.
The benefit of a cosmetic product containing postbiotics therefore lies in its ability to provide immediate benefits without the risk of altering the formula or upsetting the balance of the microbiota.
Properties of postbiotics in cosmetics
1. Strengthening the skin barrier
Postbiotics strengthen the cell junctions in the stratum corneum, protecting the skin against water loss and external aggressions.
2. Reduction of inflammation
They regulate the local immune response by limiting the production of pro-inflammatory cytokines. This is particularly useful in cases of rosacea, eczema, or reactive skin.
3. Overall anti-aging effect
- Collagen stimulation : certain postbiotics can activate fibroblasts, the cells responsible for collagen production.
- Natural antioxidants : they neutralize free radicals caused by pollution or UV rays, thereby delaying the appearance of wrinkles.
4. Hydration and suppleness
Polysaccharides derived from fermented bacteria improve water retention and make the skin more supple and radiant.
5. Protection against environmental aggressions
Their antimicrobial action limits the proliferation of pathogens and contributes to improved skin tolerance to irritants.
Technological interest: why are they easy to formulate?
Unlike live probiotics, postbiotics are stable and do not require special storage conditions or encapsulation, making them easy to incorporate into cosmetic formulas. They have a longer shelf life and their effectiveness remains constant.
Limitations and prospects
Although promising, postbiotics cannot reproduce or colonize microbiota like live probiotics do. Their effectiveness is therefore limited to the duration of application or consumption. Current research aims to better understand the molecular mechanisms involved and to standardize their production.
