Ipamorelin + CJC-1295 — the GH-axis research stack, explained

Ipamorelin and CJC-1295 are two separate peptides that are commonly dosed together in growth-hormone (GH) axis research. Ipamorelin is a pentapeptide ghrelin-receptor agonist — it triggers GH release by activating GHSR-1a, the same receptor native ghrelin targets. CJC-1295 is a modified growth-hormone-releasing hormone (GHRH) analog — it triggers GH release by activating the GHRH-receptor on pituitary somatotrophs. The two target different receptors on the same cells, and the combined stimulus produces larger and more pulsatile GH release than either alone. This primer covers both molecules, the dual-receptor rationale, the important DAC vs non-DAC distinction on CJC-1295, and what researchers studying the GH/IGF-1 axis should know.

Ipamorelin — the molecule. Ipamorelin is a synthetic pentapeptide: Aib-His-D-2-Nal-D-Phe-Lys-NH₂. Molecular weight is approximately 711.9 Da. It was developed by Novo Nordisk in the late 1990s as a selective ghrelin-receptor agonist — "selective" meaning it triggers GH release without the cortisol, prolactin, or ACTH elevations seen with earlier GHRPs (growth hormone releasing peptides like GHRP-2 and GHRP-6). This selectivity is the main reason ipamorelin displaced the earlier GHRPs in research protocols. Raun K et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552-561 is the discovery paper.

CJC-1295 — DAC vs non-DAC. CJC-1295 is where the confusion starts. The base molecule is modified GHRH(1-29) — a 29-amino-acid peptide based on the N-terminal active fragment of native GHRH, with 4 substitutions (D-Ala at position 2, Gln at position 8, Ala at position 15, Leu at position 27) to resist DPP-4 degradation. This version is sometimes called "Mod GRF 1-29" or "CJC-1295 without DAC." Half-life: approximately 30 minutes. Then there's CJC-1295 with DAC (Drug Affinity Complex) — the same 29-residue peptide plus a maleimidoproprionic acid-lysine linker that covalently binds serum albumin, extending half-life to approximately 8 days. Half-lives differ by three orders of magnitude — this is the single most important distinction to grasp when reading the literature or buying product.

Why pulsatile matters — the non-DAC rationale. Native GH is released in pulses (every 3-5 hours during sleep, with smaller daytime pulses). Chronic GH elevation, as seen in acromegaly, produces the well-characterized negative outcomes (insulin resistance, tissue overgrowth, arthropathy). Research protocols studying the GH/IGF-1 axis typically want to preserve the pulsatile pattern rather than flatten it. Non-DAC CJC-1295 (Mod GRF 1-29) paired with ipamorelin delivers a short GH pulse that mimics the native release pattern — the short half-life is a feature, not a bug. DAC CJC-1295 produces a continuous, elevated GH level that does not mimic native physiology. Which variant is "right" depends on the research question; they are not interchangeable.

The dual-receptor rationale. Ipamorelin activates the ghrelin receptor (GHSR-1a). CJC-1295 activates the GHRH receptor. Both receptors are on the same pituitary somatotroph cells, but they engage different intracellular signaling cascades — GHSR-1a couples to Gq/11 and triggers phospholipase C, while GHRHR couples to Gs and triggers adenylate cyclase. The combined stimulus produces a larger GH pulse than either agonist alone, and the synergy is reproducible across animal and human studies. Teichman SL et al. 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. J Clin Endocrinol Metab. 2006;91(3):799-805 is the foundational CJC-1295 human pharmacokinetics paper.

Administration routes and dose ranges in the literature. Both peptides are administered subcutaneously in the published research. For ipamorelin, published rodent and human protocols use doses in the 100-300 μg range per administration, typically given 1-3 times daily. For non-DAC CJC-1295 (short half-life), doses of 50-200 μg per administration 1-3 times daily are typical — the short half-life requires frequent dosing if continuous coverage is wanted. For DAC CJC-1295, weekly or bi-weekly dosing at 1-2 mg is the typical research schedule, given the ~8-day half-life. The classic pulsatile-protocol stack pairs ipamorelin 200-300 μg with non-DAC CJC-1295 100-200 μg, administered together before sleep.

What's been studied. The research literature covers GH/IGF-1 pulse characterization (multiple rodent and human studies), effects on body composition in healthy adults (small human studies, typically 12-24 weeks), pituitary-axis function after prolonged administration (rodent), and combination effects with other GH-axis agents. The human clinical evidence base is smaller than the rodent literature. Neither ipamorelin nor CJC-1295 has FDA approval for any therapeutic indication as of publication.

Storage, stability, and handling. Both peptides in prefilled pen format are stable at 2–8 °C through the labeled expiry date. Once in use, expect ~28 days at 2–8 °C for most GH-axis peptides in pen format — specific stability depends on the solvent system. Do not freeze either compound. Protect from light. Ipamorelin and CJC-1295 are both peptides of moderate hydrophobicity and are stable in the standard pen solvent systems used for the GLP-1 and recovery compounds.

What the COA should say. For ipamorelin: identity by HPLC-MS against theoretical mass (~711.9 Da), purity ≥ 98.0% by HPLC-UV, residual solvents per ICH Q3C, endotoxin by LAL. For CJC-1295: the COA must explicitly state with DAC or without DAC — the molecular weights differ substantially and the identity confirmation has to match the specific variant. Non-DAC (Mod GRF 1-29) MW is approximately 3367 Da; DAC variant is approximately 3649 Da after the maleimidoproprionic acid-lysine modification. Any COA for CJC-1295 that does not specify the variant should be considered incomplete.

Research-use only. Vivaprime supplies both ipamorelin and CJC-1295 as research reference material for qualified researchers engaged in in-vitro laboratory work. Neither compound has been approved by the FDA for any therapeutic indication. Both are on the WADA prohibited list for athletic use. Nothing on this page constitutes a therapeutic, diagnostic, or consumption recommendation. Purchasers affirm the research-use agreement at checkout.