404 J. Cosmet. Sci., 73, 404–420 (November/December 2022) Address all correspondence to I. W. Siriwardane, induni@kln.ac.lk Curcumin Against Skin Aging: A Multimechanistic Solution to a Multi-Origin Issue C. HARSHANI ALGAMA, I. W. SIRIWARDANE AND AZEEZ M. MUBARAK Sri Lanka Institute of Nanotechnology (SLINTEC), Homagama, Sri Lanka (C.H.A., I.W.S., A.M.M.) Department of Applied Computing, Faculty of Computing and Technology, University of Kelaniya, Sri Lanka (I.W.S.) Accepted for publication February 1, 2023. Synopsis Skin aging is a complex phenomenon resulting from multiple rearrangements at the molecular level. Curcumin is historically being used as an ingredient in traditional cosmetic remedies and commercial cosmetic products. Even though curcumin chemistry, its extraction, and applications in biomedical, pharmaceutical, and food industries are reviewed often, a critical review of its antiaging cosmeceutical benefits is rather limited. Therefore, this article gives an overview of the chemical and antiaging properties of curcumin, curcumin-based antiaging cosmetics, and their delivery methods. Skin antiaging benefits of curcumin are primarily derived by its ability to scavenge reactive oxygen species and interact with enzymes. However, the antioxidant and photo-prevention actions that scavenge reactive oxygen species remain the most widely researched antiaging mechanisms of curcumin. The main methods of curcumin delivery in antiaging cosmetics are direct delivery, as conjugates, and as nano-encapsulated curcumin. However, marketed curcumin cosmetics for antiaging mostly utilize direct delivery methods, implying that, despite the vast amount of research done, the application of that knowledge in making market-ready curcumin cosmetic products has not been adequate. Hence, future research on curcumin cosmetics should be more focused on effective and efficient delivery methods, improving the chemical stability of curcumin, and developing market-ready cosmetic formulations. INTRODUCTION Biological aging is a complex phenomenon that is induced by multiple factors including genetic, hormonal, and environmental ones. Skin, being the largest and most visible organ of the body, acts as a “social interface” between an individual and other members of society and is the first organ to indicate the aging signs of that individual. Due to its strategic location at the body’s interface, while subjected to intrinsic (chronologic) aging that is generally driven by genetic and hormonal influences, skin is more prone to extrinsic aging caused by environmental factors, principally ultraviolet radiation (UVR), smoking, diet, chemicals, pollutants, trauma, etc. Intrinsic aging occurs within the tissue itself with time and is biologically characterized by the reduction in dermal mast cells, fibroblasts, collagen production, and flattening of the dermal–epidermal junction/loss of rete ridges