Carnosine belongs to a family of histidyl dipeptides, consisting of l-histidine and beta-alanine. It is more prevalent in the mammalian and human tissues, whereas its analogues such as anserine, which is methylated at the Nπ of imidazole, is present in birds and fish and balenine, methylated at the Nτ of histidine, is largely present in marine mammals and reptiles (Boldyrev et al. 2013). Despite their early discovery and their prominent concentrations in certain tissues, the exact role and potential of these dipeptides are still not fully understood. Carnosine is a multifunctional dipeptide. Based on its biochemical properties, it has been suggested to be involved in acid–base balance, antioxidant defense and scavenging of lipid peroxidation products. The latter functions of the dipeptide have generated various expectations as therapeutic interventions, e.g. for the pathologies associated with enhanced generation of lipid peroxidation products.

There is a growing interest from the broad scientific community to unravel the fundamental properties as well as the potential application spectrum of carnosine and related dipeptides. As to date (December 2018), over 3300 publications are found on Web of Science when searching for ‘carnosine’, and Fig. 1 displays the fundamental (panel A) and applied research areas (panel B) in which these papers are mostly situated. The majority of fundamental research is performed in the field of biochemistry/molecular biology, pharmacology and physiology (Fig. 1a). The major application fields are neurology, diabetes, cardiovascular disease and nutrition (Fig. 1b), although the interest and relevance are broad and extends all the way to agriculture, zoology, sports sciences, etc. The wide variety of disciplines of the manuscripts in this current Special Issue is a reflection hereof.