# Peptide Cycles — Growth Hormone Axis research peptides > A data-forward literature digest on Growth Hormone Axis research peptides — CJC-1295, ipamorelin, and MOTS-c — organized around the research protocols used to study them. Citations, effect sizes, no dosing advice. A data-forward digest of CJC-1295, ipamorelin, and MOTS-c — dose levels, half-lives, trial durations, and effect sizes exactly as the published research reports them. ## The short version Peptide Cycles is a data desk, not a dosing guide. Despite the name, "cycles" here means research protocols — the specific dosing schedules, trial lengths, and follow-up windows that scientists have actually used to study three peptides that act on the growth hormone (GH) axis: CJC-1295, ipamorelin, and MOTS-c. The GH axis is the hormone chain that runs from the brain's pituitary gland, through growth hormone itself, to IGF-1, a second hormone made mainly in the liver that carries out many of GH's downstream effects. Each compound reaches the GH axis a different way. CJC-1295 mimics the brain signal that tells the pituitary to release GH. Ipamorelin acts on a separate hunger-hormone receptor that also triggers a GH pulse, but without some of the side effects seen in older compounds of its type. MOTS-c works further downstream, largely inside the cell, and its link to the GH axis is more indirect. This site reports, compound by compound, exactly what protocol each study used, how long it ran, and what it measured — never what a person should personally do with any of them. ## How GH-axis peptides are studied across research protocols The three compounds on this desk are not studied the same way, and the protocol differences are informative in their own right. CJC-1295's human pharmacokinetic work is built on single subcutaneous doses of 30 or 60 micrograms/kg, with plasma GH tracked for 6 or more days afterward and IGF-1 followed out to 9-11 days; a multiple-dose protocol extended IGF-1 elevation above baseline out to 28 days [4]. Ipamorelin's pharmacokinetic characterization used a very different design — five short 15-minute intravenous infusions across a dose range in healthy male volunteers, sampled intensively enough to resolve a roughly 2-hour terminal half-life and a single discrete GH pulse peaking about 40 minutes post-dose [9]. Its only human efficacy trial used yet another protocol: twice-daily intravenous dosing for up to 7 days in adults recovering from bowel surgery [8]. MOTS-c's research protocols look different again, because almost none of them are human interventional studies. The available data come from repeated-dosing rodent protocols — young, aged, high-fat-diet, and immobilized mice given MOTS-c over days to weeks [13], and treadmill-performance testing in mice aged 2, 12, and 22 months [16] — alongside an observational human cohort followed for a median of 26.5 months without any peptide being administered at all [14]. Reading the protocol design next to the result is often as informative as the result itself. ## What are research peptides? A peptide is a short chain of amino acids — the same molecular building blocks that make up proteins, just far fewer of them strung together. The three compounds tracked here fall into distinct structural classes. CJC-1295 is a modified analog of growth-hormone-releasing hormone (GHRH), the natural signal that triggers GH release from the pituitary. Ipamorelin is a synthetic pentapeptide built to activate the ghrelin receptor, a separate GH-triggering pathway. MOTS-c is a 16-amino-acid peptide encoded not in the cell's main genome but inside mitochondrial DNA, acting largely through metabolic enzymes rather than a hormone receptor. None of the three compounds on this desk is approved by the FDA or any other regulator for human use. All are sold and handled as research chemicals, and the data behind them range from small human pharmacokinetic studies to preclinical rodent and cell-culture work. Wherever this desk reports a dose or a study duration, it is reporting the protocol exactly as the cited study used it — never a recommendation for how a reader should use anything. ## A note on how this desk reads the evidence The three compounds sit at very different points on the evidence curve, and this desk says so directly rather than smoothing the differences over. CJC-1295's human data are limited to a handful of pharmacokinetic studies in a few dozen healthy adults, with no Phase 2 or Phase 3 program on record [3][4][5]. Ipamorelin has the most mature human trial record of the three — a completed Phase 2 randomized controlled trial — but that trial did not reach statistical significance on its primary endpoint [8], a result this desk treats as data, not as a footnote to be minimized. MOTS-c's evidence base is almost entirely preclinical, with human data limited to biomarker-association studies rather than any interventional trial [14][15]. Where a finding comes from a species other than human, or from a structurally related compound rather than the one being discussed, that distinction is stated plainly on the relevant page — as with the cardiovascular safety-pharmacology data cited on the ipamorelin page, which was generated in a different ghrelin-receptor agonist, not ipamorelin itself. Use the individual pages to read each compound in depth, or [compare all three side by side](/compare). --- A data desk for Growth Hormone Axis peptide research — every number sourced to its study design, no doses recommended, nothing for sale.