Introduction: Some peptides are developed and utilized in cosmetics, but little in vivo efficacy of the finished cosmetics containing peptides were reported, especially in the Chinese population. As a milder alternative to retinol, peptides have their advantage on high efficacy without the irritant side effects. Acetyl hexapeptide-1, a new neurotransmitter inhibitor peptide, can reduce the degree of expression wrinkles by muscle contraction, for a Botox-like activity. Signal peptides can trigger a signaling cascade and stimulate collagen, elastin, proteoglycan, glycosaminoglycan, and fibronectin production, resulting in skin rejuvenation. The test product was a cream designed to target aged skin and formulated with acetyl hexapeptide-1 and four signal peptides including palmitoyl tripeptide-5, hexapeptide-9, tetrapeptide-9, and tetrapeptide-11. The purpose of our study was to evaluate the efficacy of the five combined peptides cream ex vivo and in vivo.

Methods: Systematic studies were conducted to verify the anti-aging efficacy of the peptides-containing cream. An ex vivo study was performed on human skin explants via the topical surface application. The cream was treated on the surface of explants for 7 days in the presence of UVA/UVB exposures in the early 4 days. The non-treated samples served as a negative control. The level of collagen fibers was assessed by Masson staining and the level of collagen IV and XVII was by immunostaining. In the clinical trial, thirty-one healthy Chinese females aged between 33 and 60 with visible facial wrinkles were screened and enrolled and instructed to apply the cream for 8 weeks. Skin aging parameters were measured at 0, 4, and 8weeks by the following biophysical techniques and skin image analyses: Corneometer, Glossymeter, Cutometer, Colorimeter, Ultrascan UC22, Primos-CR, and Visia-CR. Subject self-assessments were conducted via questionnaire at each visit.

Results: The results showed the peptides cream treated ex vivo skin has relatively larger stained areas compared to the negative control, which represents an increased expression of collagen fibers in the dermis, and collagen IV and XVII in dermal-epidermal junction structure. Global anti-aging efficacy was demonstrated pigmentation of photo-damaged skin and fine lines and wrinkles. Primos-CR data indicated that the cheek lines, nasolabial folds, and forehead wrinkles experienced significant reduction to varying degrees at early 4 weeks. At 8 weeks, compared with baseline, the R7 value representing skin elasticity by Cutometer significantly decreased by 37.2% (p<0.001) and the dermal density and thickness by Ultrascan UC22 significantly increased by 33.2% (p<0.001). Skin water content was significantly increased by 35.5% and the ITA° value representing skin whiteness was improved by 7.9% after 8 weeks’ application. An increase in skin smoothness (94%), skin elasticity (87%), and skin firmness (84%) was reported by subjects. More than 74% of the subjects perceived obvious improvement in the cheek lines, nasolabial folds, and forehead wrinkles. The test cream was well accepted by subjects due to its mildness throughout the study.

Conclusion: This cream consisting of acetyl hexapeptide-1, palmitoyl tripeptide-5, hexapeptide-9, tetrapeptide-9, and tetrapeptide-11 is effective as a mild topical anti-aging formula. In vivo results revealed obvious improvement in the appearance of pigmentation, elasticity, fine lines and wrinkles. Collagen content increasing ex vivo and the dermal density and thickness increasing in vivo mutually confirmed its anti-aging mechanism of preventing collagen breakdown and boosting collagen synthesis. For those with mild anti-aging and global rejuvenation needs, this cream provides a good cosmeceutical ingredients solution.