Recent Approaches in the Treatment of Skin Ageing by Synthetic Bioactive Peptides

Over the last two decades, due to the advances in the techniques used in the design and synthesis of peptides as well as the understanding of the underlying molecular mechanisms involved in their therapeutic action on skin disorders, novel applications have been emerged for peptides as cosmeceuticals. There are several advantages in the use of   bioactive and biomimetic peptides such as availability, diverse and selective mode of action in skin physiology, and lack of immunogenic reactions that have attracted skin specialists’ attention for their potential use as anti-wrinkle agents. These peptides are known to have various biological roles against skin ageing, most prominently as extracellular matrix signal modulators and collagen synthesis stimulants. In addition, they may act as carrier peptides, antioxidants, neurotransmitter or enzyme inhibitors. However, they are facing a few obstacles for widespread applications in topical anti-ageing skin products: a) clinical evidence for the therapeutic efficacy is still limited; b) skin penetration may be weak due to their hydrophilicity, high molar mass, and binding to other ingredients; and c) high cost. Peptide transport through skin can be effectively boosted by penetration enhancers, lipophilic modifications, peptide microencapsulation, and skin microporation. There are currently more than 30 therapeutic peptides that have been occasionally introduced into the market of skin care products. This review summarizes different classes of topical peptides with proven effectiveness against skin ageing in-vivo. Moreover, the challenges of and approaches to peptide transport through skin OR (the delivery challenges and approaches) are discussed.