Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults

This pharmacokinetic and pharmacodynamic study, published in the Journal of Clinical Endocrinology & Metabolism, provided a detailed characterization of the effects of CJC-1295 (with DAC) on the GH and IGF-1 axes in healthy adults. The protocol included ascending single doses and weekly multiple doses, with frequent hormonal sampling to delineate the complete temporal profile of the response.

Results demonstrated that a single subcutaneous dose of CJC-1295 produced dose-dependent increases in mean GH concentrations of 2- to 10-fold above baseline values, sustained for 6 days or more. In parallel, IGF-I (insulin-like growth factor I) concentrations increased 1.5- to 3-fold, remaining elevated for 9 to 11 days after injection. Following weekly multiple doses, additional accumulation with even more sustained elevation was observed.

A pharmacologically relevant aspect was the preservation of the pulsatile pattern of GH secretion during treatment. Unlike exogenous GH administration (which produces non-physiological peaks), CJC-1295 amplified the natural GH pulses, maintaining the amplitude and frequency of the secretory rhythm — a profile considered safer and more physiological in the long term.

The safety profile was excellent: no serious adverse reactions were observed. The most common events were transient injection site erythema and mild headache. There were no clinically relevant changes in fasting glucose or other metabolic parameters. This study is considered the fundamental reference for CJC-1295 pharmacokinetics and pharmacodynamics in humans, being widely cited in the literature on GH secretagogues.