CJC-1295 with DAC and Ipamorelin: Two Receptors, One Fixed Ratio

The blend holds two peptides addressing two receptors. CJC-1295 with DAC is a GHRH-receptor analogue extended with a maleimidopropionic acid group that binds serum albumin covalently; ipamorelin is a pentapeptide agonist at GHS-R1a, the ghrelin receptor. That is one ligand per receptor - a cleaner pharmacological story than many fixed blends.

Teichman and colleagues put a number on the DAC form's pharmacokinetics in healthy adults: an estimated half-life of roughly six to eight days, with IGF-I remaining elevated for over a week after a single administration and evidence of accumulation across repeated administration. That sustained GHRH-receptor engagement is the defining property of this pairing's GHRH arm.

Ipamorelin belongs to a different class entirely. Raun and colleagues identified it within a series derived from GHRP-1 and confirmed with antagonist pharmacology that it works through a GHRP-like receptor rather than the GHRH receptor. Its published distinguishing feature is selectivity - it released GH with potency comparable to GHRP-6 in rat and swine models without raising ACTH or cortisol above GHRH-stimulated levels.

This blend is unusual among combination products in having a published pharmacological argument behind it, and that deserves to be stated clearly rather than buried under caveats.

GH release from the pituitary is governed by at least three inputs: GHRH, growth hormone-releasing peptides acting at GHS-R1a, and somatostatin. Because GHRH-receptor and GHS-R1a agonists engage separate receptors with separate downstream coupling, their combined effect need not be additive - and in the human literature it generally is not. Veldhuis and Bowers, infusing GHRH and GHRP-2 simultaneously in 47 men, treat GHRH-GHRP synergy as an established phenomenon and devote their study to characterising what modulates it.

Two qualifications belong immediately alongside that. The first is molecular: the synergy literature was built with GHRH(1-29) or GHRH(1-44) and with GHRP-2 or GHRP-6. Extending it to CJC-1295 with DAC and ipamorelin is a class-level inference - a reasonable one, given that ipamorelin's receptor was confirmed pharmacologically to be the GHRP receptor, but an inference rather than a measurement.

The second is that the effect is design-dependent. Tiulpakov and colleagues gave eight healthy volunteers GHRH(1-29), GHRP-2, and both together; the combined response exceeded either agent alone, but it was not significantly greater than the sum of the individual responses. Combination effects depend on relative exposure of the two agents, which is exactly the variable a fixed-ratio vial removes from the experimenter's control.

One thing, and it is preclinical. Reviewing peptides for orthopaedic clinicians in 2026, Mayfield and colleagues report that CJC-1295 combined with ipamorelin improved maximum tetanic tension in murine models of glucocorticoid-induced muscle loss - and state directly that the finding is limited to animal studies.

That is a genuine combination-specific result. It is also a single functional endpoint in a mouse model of a specific insult. It does not establish a human effect, does not identify the contribution of either component, and does not speak to ratio.

Everything else remains unmeasured. There is no combined pharmacokinetic study - no description of how a multi-day-half-life GHRH analogue and a short-acting secretagogue interact in exposure terms when co-administered. There is no combined safety observation of any duration. There is no ratio study.

The stated composition is 5 mg CJC-1295 with DAC and 5 mg ipamorelin. As with any blend, the mass figures mislead about molecule counts: CJC-1295 with DAC weighs 3647.2 g/mol against ipamorelin's 711.9, so the vial supplies roughly five times as many ipamorelin molecules as CJC-1295 molecules. Given that Tiulpakov and colleagues attributed their negative synergy result to relative molar quantities, this is not a trivial detail - and no published work identifies what ratio of GHRH analogue to secretagogue is appropriate.

The endocrine context adds constraints that a component-by-component reading misses. Somatostatin opposes both pathways, and the human synergy work found the combined response strongly modulated by age, abdominal-visceral fat and IGF-I status. Fixed-ratio combinations are least well suited to pharmacology of that kind.

It is worth being precise about the overall evidence position. The receptor logic is sound and published. Both components have real characterisation literatures, one of them human. But the specific fixed-ratio preparation has never been studied in humans; combined pharmacokinetics and combined safety are unreported; and the single combination result available is a functional endpoint in mice.