Effect of Protease-Treated Royal Jelly Extract on Facial Wrinkles: A Placebo-Controlled, Double-Blind, Parallel-Group Study

Several human studies show positive signals, while research methods and sample sizes continue to develop.

• Level A · Stronger Clinical Evidence
• Level B · Emerging clinical evidence with positive signals
• Level C · Early human research exploring benefits
• Level D · Scientific groundwork from lab and animal studies
• Emerging · Emerging topic under active research

Abstract (original English)

Background No clinical trials have reported on the wrinkle-improving effects of cosmetics which activate stem cells in vitro. Aims To evaluate the anti-wrinkle effects of protease-treated royal jelly (pRJ)-containing cream application to the skin. Materials & methods Seventy healthy Japanese women concerned about skin aging were treated with pRJ-containing cream or placebo for 12 weeks using the split-face method in a placebo-controlled, double-blind, parallel-group study. Results The pRJ-containing cream group showed an improvement in the maximum depth and average depth of the biggest wrinkle in the crow's feet wrinkle, along with increased water content of the stratum corneum and dermal thickness, compared to the placebo group. Significant decreases in the relative amount of bacterial microbiome of the cheeks were observed only in the pRJ-containing cream group. In the ex vivo study, expression of COL17A1, epidermal stem cell function marker, was significantly up-regulated with the use of the pRJ-containing cream compared with the placebo cream. Conclusion This is the first study to demonstrate the wrinkle-improving effects of pRJ. Our results suggest that pRJ not only controls stratum corneum water content, dermal thickness, and bacterial microbiome, but also affects stem cell competition and mesenchymal stem cell activation. pRJ can reduce or eliminate certain skin concerns

Evidence level

Several human studies show positive signals, while research methods and sample sizes continue to develop.

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