Capromorelin

Capromorelin is a synthetic, orally active growth hormone secretagogue that functions as an agonist at the ghrelin receptor, formally the growth hormone secretagogue receptor 1a (GHS-R1a) ^[1]. Chemically it belongs to a class of small-molecule ghrelin mimetics developed to reproduce the effects of the endogenous peptide hormone ghrelin, which is secreted by cells in the stomach and regulates appetite, food intake, and growth hormone release ^[1][2]. By binding GHS-R1a in the hypothalamus and pituitary, capromorelin stimulates the release of growth hormone and, through central appetite circuits, increases hunger ^[2].

The compound was originally investigated in humans as a growth hormone secretagogue for conditions such as frailty and cachexia, where increasing growth hormone, lean mass, and appetite is desirable ^[1]. It subsequently found its most established use in veterinary medicine. Capromorelin oral solution was approved by the United States Food and Drug Administration in 2016 under the brand name ENTYCE for stimulation of appetite in dogs, and a feline formulation named Elura was later approved for management of weight loss in cats with chronic kidney disease ^[2].

Research applications include appetite stimulation, treatment of anorexia and cachexia, body-weight gain, and study of the broader physiology of ghrelin, which also encompasses gut motility, glucose metabolism, and neuroendocrine function ^[1][2]. Ghrelin receptor agonists have additionally been explored for anti-inflammatory and immunomodulatory properties ^[1]. Regulatory status is well defined in the veterinary sphere, where capromorelin is an approved drug supplied as an oral solution; in human medicine it remains investigational ^[2].

Capromorelin is a ghrelin-receptor agonist and growth-hormone secretagogue approved as a veterinary appetite stimulant but not for human use, and human safety data are limited. As a GH secretagogue, class effects include increased appetite and raised growth hormone and IGF-1, with potential for fluid retention, joint discomfort, insulin resistance and elevated blood glucose; reported effects include hypersalivation and gastrointestinal upset.

Capromorelin began life as a human drug candidate, synthesized by Pfizer in the 1990s under the code CP-424,391 as an orally active growth hormone secretagogue intended to combat age-related frailty and muscle loss. Although it advanced into human studies, it did not reach the market for that purpose, and the molecule lay largely dormant until it found a second life in veterinary medicine.

The company Aratana Therapeutics recognized that its reliable stimulation of appetite through the ghrelin receptor was itself valuable, and developed it as an oral solution for dogs. In 2016 the United States Food and Drug Administration approved it under the name Entyce, making it the first drug of its kind ever approved to stimulate appetite in any species. A feline formulation, Elura, followed in 2020 for weight management in cats with chronic kidney disease, extending the reach of a compound that had once been aimed at human aging.

Capromorelin has built a reputation as a dependable, well-characterized appetite stimulant, valued precisely because its effects are large, predictable, and dose-related rather than subtle. By mimicking the body's own hunger hormone ghrelin, it addresses the root signal for appetite rather than masking a symptom, and it raises growth hormone and IGF-1 as a physiological bonus. According to PubMed, a randomized, masked, placebo-controlled study in healthy Beagles found that capromorelin increased food consumption by more than 60% over placebo within four days while being well tolerated [Zollers et al., 2017, https://doi.org/10.1186/s12917-016-0925-z].

That combination of a clear mechanism, robust measurable effect, and a genuine regulatory approval makes it a standout tool for supporting intake and healthy weight. In fairness, its documented effects include modest rises in blood glucose and insulin consistent with ghrelin receptor activation, and it is best appreciated as a first-in-class agent whose deepest evidence base lies in veterinary use.