# Compare CJC-1295 / Ipamorelin, CJC-1295 and Ipamorelin — Biotide Peptides

> A side-by-side comparison of three Growth Hormone Axis research peptides — CJC-1295 / Ipamorelin, CJC-1295, and Ipamorelin — across peptide class, evidence base, pharmacokinetics, regulatory status and key cautions.

Where the CJC-1295 + ipamorelin research stack, its GHRH-analogue arm, and its selective GHRP arm converge, diverge, and — most importantly — what the evidence behind each actually amounts to.

## The short version

This page lines up [CJC-1295 / Ipamorelin](/cjc1295-ipamorelin), [CJC-1295](/cjc-1295), and [Ipamorelin](/ipamorelin) on the dimensions that matter most for reading this class of research peptides: mechanism, evidence model, pharmacokinetics, regulatory standing, and the single defining caution for each. The headline is efficient. All three stimulate the GH/IGF-1 axis, but through distinct mechanisms and from very different evidence positions: CJC-1295 has published human pharmacodynamic data documenting sustained multi-day GH and IGF-1 elevation [3]; ipamorelin has one published Phase 2 trial that missed its endpoint [14]; and the combination has never been studied as a fixed blend in any controlled trial. None is an approved medicine, and none is presented here with a human dose.

## The comparison matrix

| Dimension | CJC-1295 / Ipamorelin | CJC-1295 | Ipamorelin |
| --- | --- | --- | --- |
| Peptide class | GHRH analogue (CJC-1295) + GHS-R1a agonist / GHRP (ipamorelin) — research combination | Tetrasubstituted hGRF(1-29) analogue; DAC and no-DAC variants | Synthetic pentapeptide; selective GHS-R1a / ghrelin receptor agonist |
| Most-studied in | Combination synergy (receptor cross-talk); GHRH-analogue class human body composition [1][5][7] | GH and IGF-1 pharmacodynamics; serum proteomics; anti-doping detection [3][10][11] | GH selectivity; bone growth (rats); postoperative ileus (humans); chemotherapy weight loss (ferrets) [6][14][16] |
| Evidence base (model) | Separate component studies + receptor cross-talk cell work; no fixed-blend human trial [2][5] | Human PK/PD studies (healthy adults) + rat albumin-binding chemistry [3][4] | Rat and ferret animal work; 1 human PK study (IV, n=8/dose); 1 Phase 2 RCT (missed endpoint) [14][15] |
| Pharmacokinetics | DAC half-life 5.8–8.1 days vs. ipamorelin ~2 h IV terminal half-life — fundamentally mismatched timescales [3][15] | DAC: half-life 5.8–8.1 days, GH elevated ≥6 days, IGF-1 elevated ≥9 days per dose [3] | Terminal half-life ~2 h (IV); GH pulse peaking ~40 min post-dose; no subcutaneous human PK data [15] |
| Regulatory / WADA status | Not approved; both components WADA S2 prohibited; compounding status: removed from Category 2, PCAC review 2024 | Not approved; WADA S2 prohibited; not recommended for 503A compounding bulks list [9] | Not approved (Phase 2 failed); WADA S2 prohibited; removed from 503A Category 2, PCAC reviewed Oct 2024 |
| Key caution | Fixed blend never clinically tested; mismatched half-lives make net GH exposure uncharacterized [2][3][15] | DAC vs. no-DAC confusion; sustained multi-day IGF-1 elevation; limited long-term human safety data [2][3] | Phase 2 missed endpoint; class-level cardiac signal from related GHS-R1a agonist; no long-term human safety database [13][14] |

## Peptide class

All three work on the GH/IGF-1 axis, but through distinct molecular mechanisms. CJC-1295 is a GHRH analogue: it binds the GHRH receptor (a class-B GPCR) on pituitary somatotrophs and activates the Gs/cAMP/PKA cascade [8]. Ipamorelin is a synthetic pentapeptide that binds the ghrelin receptor (GHS-R1a) on the same cells and raises intracellular calcium via a Gq pathway — mechanistically independent from the GHRH receptor [6]. The combination exploits that independence: because the two arms use different intracellular switches, co-stimulating both produces a GH pulse larger than either alone [5][7].

## Most-studied in

Each entry has a distinct research territory. CJC-1295 / Ipamorelin research centers on the synergy concept — dual-receptor co-stimulation for enhanced GH release — contextualized by the GHRH-analogue class human evidence on body composition [1][5][7]. CJC-1295 alone is most studied for its pharmacodynamic profile in humans: how much GH and IGF-1 it raises, for how long, with what kinetics [3][11]. Ipamorelin's most-cited contribution is its selectivity characterization in animal models [6], plus a single human trial in a bowel-resection context and the most recent ferret chemotherapy weight-loss study [12][14].

## Evidence base (model)

This is where the three genuinely separate. CJC-1295 has the strongest individual human pharmacodynamic dataset: published PK/PD studies in healthy adults documenting multi-day GH and IGF-1 elevation, plus a serum proteomic shift study in young men [3][10][11]. Ipamorelin has the only published Phase 2 human trial of any compound on this desk — but that trial enrolled 114 adults in a bowel-resection context and missed its primary endpoint [14]. The combination has no controlled human trial of the fixed blend at all; its combined pharmacology is inferred from the component data and receptor cross-talk cell work [5]. In short: CJC-1295 is the most pharmacodynamically characterized, ipamorelin is the most clinically tested (but without demonstrated efficacy), and the combination is the most widely discussed but the least directly studied.

## Pharmacokinetics

The pharmacokinetic mismatch between the two components is one of the underappreciated complications of the stack. CJC-1295 with DAC has a half-life of 5.8–8.1 days in humans, with GH elevated for 6 or more days and IGF-1 for 9–11 days or more per dose [3]. Ipamorelin has a terminal half-life of approximately 2 hours from IV infusion studies, with GH peaking around 40 minutes post-dose [15]. The no-DAC form of CJC-1295 (Mod GRF 1-29) has a half-life of roughly 30 minutes, which puts it closer to ipamorelin's timescale but far from the DAC form. Pairing a multi-day agent with a 2-hour agent means the intended pulsatile synergy profile and the net GH exposure are not characterized for any specific dosing interval. Community protocols choose a protocol from among several circulating options with no controlled-trial basis for choosing between them [2].

## Regulatory / WADA status

None of the three entries is approved by the FDA, EMA, or any major regulator as a human medicine. All are prohibited in sport at all times under WADA Section S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics). Both CJC-1295 and ipamorelin acetate were added to the FDA's interim 503A Category 2 bulk-substances list (restricting compounding pharmacy use) in September 2023, then removed from Category 2 in September 2024 after nominator withdrawal; both were reviewed at the October 29, 2024 Pharmacy Compounding Advisory Committee meeting, where they were not recommended for the approved 503A bulks list [9]. Research-grade versions are sold only for laboratory research use.

## Key caution

Each entry carries a defining caveat. For the combination, it is the absence of any fixed-blend clinical trial combined with the fundamentally mismatched half-lives of its two components, meaning the net GH exposure profile is unknown for any specific protocol [2][3][15]. For CJC-1295, it is the sustained multi-day IGF-1 elevation it produces — a real pharmacodynamic effect that lacks long-term safety data, compounded by routine DAC/no-DAC confusion that understates how different the two forms actually are [2][3]. For ipamorelin, it is that its one human Phase 2 trial failed [14] and a 28-day preclinical study of a related GHS-R1a agonist found dose-dependent myocardial degeneration in rats [13] — a class-level cardiovascular signal with no equivalent long-duration ipamorelin safety study in any species to either replicate or rule it out. Reading the three together, the pattern is consistent: compelling pharmacological mechanisms, real human pharmacodynamic data for one component, and a widening gap between mechanism and clinical evidence as one moves toward the combined protocol and its long-term implications.

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A peer-reviewed briefing on GH-axis research peptides — citations anchored to primary literature, no products, no clinical recommendations.