The human skin serves as an essential shield against the external world, constantly facing environmental assaults and microbial threats. When this vital barrier is compromised, it can lead to various skin conditions, impacting physical well-being and psychological health. Traditional treatments often rely on harsh chemicals and pharmaceuticals. A growing body of research highlights the critical importance of a balanced skin microbiome for optimal health. This dynamic ecosystem of bacteria, fungi, and viruses acts as a crucial defense line, repelling harmful agents and regulating essential skin functions. An imbalance in microbial diversity (dysbiosis) is linked to numerous skin disorders, leading to a shift towards microbiome-friendly skincare solutions. Topical probiotics, which are living microorganisms applied directly to the skin, offer significant potential health benefits. Micrococcus luteus Q24, a native commensal of the skin, is a promising candidate due to its ability to thrive in the skin environment and its potent antimicrobial activity against pathogenic bacteria. While many cosmetic probiotics are gut-derived (Bifidobacterium, Lactobacillus), M. luteus Q24 provides a distinct approach with targeted antimicrobial action against skin pathogens like C. acnes and S. aureus, and has shown efficacy in improving blemishes, hydration, and reducing signs of aging. Furthermore, delivering live probiotics in a meticulously formulated balm can provide a protective and nourishing environment crucial for their viability and efficacy, potentially amplifying benefits synergistically with prebiotics and functional actives.
Methods
This study involved screening ingredients for compatibility with M. luteus Q24 using a modified minimum inhibitory concentration assay. Live cell counts were measured to determine the growth-promoting effects of selected prebiotics and functional actives on M. luteus Q24 over 24 hours, including dose-response relationships for some ingredients. A pilot cosmetic trial assessed the efficacy of two M. luteus Q24-enriched balms applied twice daily for seven days on target dry skin areas in twelve healthy adults using an AI-driven skin analyser device for measurements like hydration, pores, spots, wrinkles, and keratin levels.
Key Findings
• Green tea extract showed complete incompatibility with M. luteus Q24, while seven others inhibited growth only at high, potentially non-cosmetic concentrations.
• Oil-based functional actives like vitamin E, cocoa butter, pomegranate seed oil, grape seed oil, olive squalene, olive oil, and flax seed oil significantly boosted M. luteus Q24 growth, exhibiting a greater impact than oatmeal, the only effective prebiotic tested.
• Pomegranate seed oil, oatmeal, olive squalene, and flax seed oil unexpectedly enhanced M. luteus Q24 growth throughout the study, suggesting potential prebiotic properties.
• Vitamin E showed an optimal growth-promoting concentration of 0.6%.
• Coconut oil displayed a biphasic response, initially stimulating then inhibiting growth, suggesting potential antibacterial properties.
• In the cosmetic trial, Balm B significantly reduced keratin levels, wrinkles, and pore size, and increased hydration.
• Balm A significantly reduced keratin and spots, and also increased hydration.
• After just 4 days, Balm A showed mean percentage reductions in pores, spots, wrinkles, and keratin scores.
• After 4 days, Balm B showed mean percentage reductions in pores, spots, wrinkles, and keratin scores, along with an increase in the hydration score.
• No adverse events were reported by participants.
This research successfully demonstrated the feasibility and efficacy of a topical balm enriched with Micrococcus luteus Q24 for enhancing skin health. The study established the compatibility of various ingredients, including prebiotics and functional actives, with M. luteus Q24, and importantly, identified substances, particularly oil-based actives, that effectively promoted its growth. The subsequent pilot cosmetic efficacy trial confirmed the balm’s ability to significantly improve skin hydration and reduce visible signs of aging, highlighting its potential as a microbiome-friendly cosmetic product. The novelty lies in evaluating a skin-native probiotic (M. luteus Q24) delivered in a balm formulation, which is hypothesized to provide an optimal environment for the probiotic to thrive and exert its benefits. While acknowledging the limitations of the current pilot study, including the lack of a placebo arm and a small participant pool, these findings provide a strong foundation for future research. Larger, placebo-controlled trials are warranted to further validate the observed benefits and explore the long-term effects of M. luteus Q24-enriched balms on the skin microbiome, ultimately contributing valuable insights towards developing targeted skincare solutions.
Link to the study: https://www.mdpi.com/2079-9284/12/3/105
