The body’s own growth hormone-releasing hormone survives minutes in the blood. CJC-1295 was engineered to send the same signal for days, and the two versions sold under the name differ in exactly that.
CJC-1295 · Growth hormone-releasing hormone analogue
Growth hormone is released by the pituitary gland in pulses, and the instruction to release it comes from a hormone made in the brain: growth hormone-releasing hormone, or GHRH. Native GHRH is broken down within minutes. CJC-1295 is a modified copy of its active segment, studied because it can be made to persist far longer. Evidence comes from rat pituitary work and small human trials of the long-acting form in healthy adults.
CJC-1295 is built on the first 29 amino acids of GHRH, the segment that carries the hormone’s activity. Four amino-acid substitutions protect that segment from the enzymes that clear native GHRH, chiefly DPP-IV (dipeptidyl peptidase-4, an enzyme in blood that trims peptides). That tetra-substituted backbone is what is sold as “CJC-1295 without DAC”, also called modified GRF(1–29).
The DAC version adds a Drug Affinity Complex: a reactive chemical group at one end of the peptide that forms a permanent (covalent) bond with albumin, the most abundant protein in blood. Bound to albumin, the peptide is carried around with it and cleared slowly. In the discovery work in rats, the albumin-bound conjugate still activated the GHRH receptor on the pituitary, and the reported half-life moved from minutes to days (Jétté et al., 2005). The two versions share a backbone but behave differently in the body, and they should not be treated as interchangeable.
The clinical evidence concerns the DAC form. A phase 1 randomised, placebo-controlled study in healthy adults reported that single or repeated subcutaneous injections raised growth hormone and IGF-1 (insulin-like growth factor 1, the liver-made hormone that carries much of growth hormone’s downstream signal) for a week or more after a single dose (Teichman et al., 2006). A companion study in healthy men found that the pituitary continued to release growth hormone in pulses despite continuous stimulation, rather than switching to a flat output (Ionescu and Frohman, 2006). Those are pharmacology studies: they measured hormone levels in a small number of healthy volunteers, not clinical outcomes in patients.
No equivalent human trials of the “without DAC” form exist under that name. Its expected behaviour is inferred from the shared backbone and from older work on GRF(1–29) analogues, which produce a brief pulse of growth hormone release rather than a sustained rise.
Covalent albumin binding is one of several half-life strategies in peptide chemistry. Semaglutide, for comparison, reaches once-weekly dosing through a fatty-acid side chain that binds albumin reversibly, not covalently (Lau et al., 2015) — a related idea, different chemistry.
The 2006 trials were small, short and in healthy adults; they did not examine long-term effects, clinical outcomes, or any population with a medical condition. Findings for the DAC form do not validate the “without DAC” form, and neither validates a blend with other peptides. The compound has no completed development programme and no regulatory approval. Substances that release growth hormone are prohibited in sport under WADA category S2.
CJC-1295, with or without DAC, is not an approved medicine in Australia, and no approval elsewhere was identified. Growth hormone-releasing factors are prohibited at all times in sport under WADA category S2.
Sources and status checked 2026-09-22
CJC-1295 — sizes and pricing