Notes on the peptides most frequently cited in current research literature.

A pentadecapeptide derived from a protective protein found in gastric juice. Studied largely in the context of tissue repair pathways and gastrointestinal models, with a particular focus on tendon, ligament, and mucosal research. Sits at the centre of a large and still-growing body of preclinical literature, and is often the first compound new researchers encounter when surveying the field.

A synthetic fragment of the naturally occurring Thymosin Beta-4 protein, which is involved in actin sequestration and cellular migration. Investigated in repair and regeneration models, often alongside BPC-157 in comparative studies. Most of the published work focuses on its role in the early stages of tissue response rather than long-term outcomes.

A copper-binding tripeptide first identified in human plasma in the 1970s. Most frequently cited in dermal and connective tissue research, often in topical formulations, where its copper-chelation properties are central to the mechanism under study. Has a longer publication history than most compounds on this list, with literature spanning wound research, hair follicle studies, and skin-ageing models.

A GLP-1 receptor agonist. The subject of extensive metabolic and glycaemic regulation literature, and the compound responsible for much of the recent mainstream attention on the GLP-1 class. Research contexts span glucose regulation, appetite signalling, and cardiovascular endpoints, with a publication volume that now dwarfs most other peptides in this field map.

A dual GIP/GLP-1 receptor agonist, and a more recent entrant than Semaglutide. Studied in similar metabolic contexts but with the added GIP receptor activity producing a distinct pharmacological profile in the literature. Comparative studies between Tirzepatide and single-agonist GLP-1 compounds are an active area of current research.

A growth hormone secretagogue developed in the 1990s. Studied for its selectivity profile relative to earlier compounds in its class — specifically, the absence of significant cortisol or prolactin elevation in the published models. Frequently appears in research alongside CJC-1295, where the two are investigated in combination for their complementary mechanisms.

A growth hormone-releasing hormone (GHRH) analogue, modified to extend its half-life relative to native GHRH. Frequently appears in literature alongside Ipamorelin in combination studies, where the GHRH and secretagogue mechanisms are examined together. Research interest centres on pulsatile release patterns and how they differ from earlier GH-related compounds.

A synthetic analogue of alpha-melanocyte-stimulating hormone, with affinity for several melanocortin receptor subtypes. Investigated in pigmentation and appetite regulation models, with the broader receptor activity making it a useful tool compound in melanocortin system research more generally.

A heptapeptide developed from a naturally occurring immunomodulatory protein (Tuftsin), originally synthesised in Russia. Studied in anxiolytic and cognitive research contexts, with much of the foundational literature published outside the English-language journal system. Recent years have seen increased Western research interest, though the compound remains less widely cited than others on this list.

A heptapeptide fragment of ACTH (adrenocorticotropic hormone), also originating from Russian research programmes. Most often cited in neurotrophic and cognitive research literature, with published work on BDNF expression and related neurochemical pathways. Like Selank, much of its early literature sits outside mainstream English-language indexing, which is part of why it tends to be encountered later than the compounds higher on this list.