What are the benefits of cosmetic probiotics for the skin?

Another key feature of probiotic-based cosmetics: their hydrating potential. Necessary for all skin types, good hydration is the foundation of a cosmetic routine and has numerous effects: improving skin texture, reducing feelings of discomfort and redness, preventing skin ageing...

The local application in vitro of Lactobacillus plantarum has recently been studied by a group of researchers. They found that treating epidermal cells with a preparation based on this probiotic led to anincrease in hyaluronic acid content, which has a strong moisturising power. The supposed mechanism of its action would be its ability to induce the production of cytokine IFN-γ in order to activate the NF-κB pathway through a synergistic effect with TNF-α. This results in the increase in the expression of hyaluronate synthase mRNA in fibroblasts, thus producing more hyaluronic acid. This enhances skin hydration and also helps to combat wrinkles.

The excessive attack of free radicals on biological tissues such as chromosomes, mitochondria, cell membranes, and connective tissues accelerates the ageing of the body and leads to several skin discomforts (pigmentation spots, more pronounced skin sagging...). Probiotics are interesting molecules to combat free radicals. Indeed, a study conducted on rats has shown that the topical application of Lactobacillus rhamnosus was able to reduce the content of free radicals in the skin cells.

Furthermore, several studies have shown that the combination of probiotics and well-known antioxidant molecules has synergistic effects. Indeed, the combination of β-nicotinamide mononucleotide (NMN) and lactic bacteria such as Lactobacillus fermentum helps to increase the levels of superoxide dismutase (SOD) and catalase in the skin, thereby enhancing its overall antioxidant capacity. Indeed, SOD and catalase are endogenous antioxidant enzymes that play a key role in protecting the skin from free radical attack and regulating oxidative stress.

Some probiotics also exhibit intriguing anti-inflammatory properties that can reduce the intensity of redness and alleviate skin irritation caused by exposure to UVB rays, which are responsible for sunburn. Indeed, the strain Lactobacillus reuteri has demonstrated its ability to inhibit the angiotensin-converting enzyme, which is involved in the photoaging of the skin. Moreover, this probiotic has a regulatory effect on the intracellular level of interleukin-8, a pro-inflammatory cytokine that is upregulated in cases of psoriasis , among other conditions.

Finally, probiotics are a good supplement to treatments prescribed by dermatologists in cases of acne and inflammatory eczema. Several studies have focused on the effects of these microorganisms in patients with either of these skin conditions and the results obtained have proven their effectiveness in reducing the severity of lesions.

In recent years, there has been an increase in the use of probiotics in cosmetics targeting pigmentation marks. Several researchers have investigated to better understand this effect of probiotics and have shown that certain strains could interfere with the expression of tyrosinase, an enzyme involved in the process of melanogenesis. More specifically, tyrosinase catalyses the transformation of tyrosine, an amino acid, into melanin, the pigment responsible for skin colour. Among the probiotics with anti-tyrosinase activity, we can notably mention Bifidobacterium and Lactobacillus plantarum, bacteria that have been the subject of several in vitro studies.