GROWTH HORMONE AXIS / COMPARISON
Three Peptides, Side by Side
Where the three GH axis peptides converge, where they diverge, and — most precisely — how far the evidence behind each actually reaches.
The short version
This page lines up tesamorelin, MOTS-c and CJC-1295 on the dimensions that matter most when reading research peptides: molecular class, primary study context, evidence model, studied administration route, regulatory standing, and the single most important caution for each. The headline is precise. All three relate to the GH/IGF-1 axis, but they sit at completely different points in the regulatory and evidence spectrum: tesamorelin is an FDA-approved prescription drug for a narrow indication with multiple Phase 3 RCTs [1][6]; CJC-1295 has controlled pharmacokinetic data in healthy adults but no efficacy trials and no approval [16][17]; MOTS-c has compelling animal mechanistic data and one human biomarker association study — no interventional human evidence at all [9][11]. None is presented here with a human dose.
The comparison matrix
| Dimension | Tesamorelin | MOTS-c | CJC-1295 |
|---|---|---|---|
| Peptide class | Synthetic 44-aa GHRH analogue (N-terminal hexenoyl modification) | 16-aa mitochondrial-derived peptide (MT-RNR1 encoded) | Synthetic 29-aa GHRH analogue (4 substitutions ± DAC albumin-binding moiety) |
| Most-studied in | Visceral fat and hepatic fat in HIV lipodystrophy | Skeletal-muscle glucose handling, AMPK activation, physical performance | GH and IGF-1 pharmacokinetics in healthy adults |
| Evidence base (model) | Multiple Phase 3 RCTs in human HIV cohorts [1][6] | Animal (mice) + 1 human biomarker cohort (observational) [9][11] | Human PK studies (healthy adults); no efficacy RCTs [16][17] |
| Administration studied | Subcutaneous, 2 mg/day, in RCTs [3][6] | Intraperitoneal or subcutaneous in mice; no human route established [11] | Subcutaneous (30–90 µg/kg) in PK studies [16][17] |
| Regulatory / WADA status | FDA-approved (HIV lipodystrophy only); WADA S2 prohibited | Not approved; WADA prohibited (metabolic modulator category) | Not approved; not on 503A bulks list; WADA S2 prohibited |
| Key caution | Approved indication is narrow; off-label use is investigational; fat reaccumulates on discontinuation [5] | No human efficacy trials; rodent doses cannot be extrapolated [9][10] | Long-acting programme discontinued; no efficacy RCTs; DAC/no-DAC identity confusion [13][16] |
Peptide class
The three span a substantial structural range. Tesamorelin and CJC-1295 are both synthetic GHRH analogues — tesamorelin covering all 44 residues of native GHRH with an N-terminal hexenoyl cap, CJC-1295 working from a shorter 29-residue scaffold with four substitutions and, in its DAC form, covalent albumin binding. Both act at the same receptor (GHRHR) on pituitary somatotrophs [13]. MOTS-c is structurally unrelated to either: a 16-amino-acid mitochondrial-derived peptide that acts at AMPK via the folate cycle, at CK2 directly, and at the nucleus under metabolic stress [8][10]. Grouping all three under "GH axis" reflects functional overlap in the metabolic space they affect, not common mechanism.
Most-studied in
Each peptide has a home territory. Tesamorelin's controlled human trial record is almost entirely in HIV-infected adults with antiretroviral-associated lipodystrophy — visceral fat and hepatic fat are the primary outcomes [1][3][6]. MOTS-c is studied primarily in skeletal muscle: AMPK-dependent glucose handling, muscle atrophy prevention, and physical performance in aged mice [8][11]; the human biomarker work is in a renal-failure cohort [9]. CJC-1295's published human data are focused on pharmacokinetics — how long GH and IGF-1 stay elevated after a dose in healthy adults [16][17].
Evidence base (model)
This is where the three genuinely diverge. Tesamorelin has the strongest and most directly applicable human evidence: five RCTs pooled in a 2026 meta-analysis, multiple Phase 3 studies and a 52-week durability study, all in human subjects [1][5][6]. CJC-1295 has controlled human data but only pharmacokinetic: the studies measured GH and IGF-1 curves in healthy adults — not clinical outcomes in any disease [16][17]. MOTS-c has the least human footing of the three: no published interventional human trials, only cell culture, animal models (predominantly mice), and one observational biomarker-association cohort [9][11]. The gap between tesamorelin and MOTS-c illustrates how far a GH-axis peptide can travel — or stop — on its journey toward clinical validation.
Administration studied
Routes and doses track the research questions. Tesamorelin was studied at 2 mg/day subcutaneously in all major clinical trials [3][6]. CJC-1295 was given subcutaneously at 30 or 60 µg/kg (single dose) or 60 or 90 µg/kg (pulsatile studies) in healthy adults [16][17]. MOTS-c was administered intraperitoneally or subcutaneously in mice at doses ranging from 0.5 to 15 mg/kg/day; there is no established human route, formulation or dose [11]. For MOTS-c, community dosing protocols have no peer-reviewed basis.
Regulatory / WADA status
All three are subject to WADA prohibition in sport. Tesamorelin is prohibited under Section S2 (peptide hormones and growth factors) as a GHRH analogue; it is also an FDA-approved prescription drug but only for HIV lipodystrophy — prescribing it for other conditions or obtaining it as a research chemical falls entirely outside the regulatory protection of that approval [2][7]. CJC-1295 was explicitly reviewed and not recommended for the 503A compounding bulks list by the FDA Pharmacy Compounding Advisory Committee in 2024; it is prohibited under WADA S2 [13]. MOTS-c is not specifically named in FDA guidance but is treated as a prohibited metabolic modulator by anti-doping authorities.
Key caution
Each peptide carries a defining caveat. For tesamorelin it is the width of the approved indication — the approval is real but narrow, off-label use is investigational, and fat reaccumulates rapidly on discontinuation [5][7]. For CJC-1295 it is the collapse of the development programme and the absence of any efficacy trial — the pharmacokinetic data confirm you can extend GH elevation, but no controlled study has answered what that elevation produces clinically; the DAC/no-DAC naming confusion in community sources compounds the interpretive problem [13][16]. For MOTS-c it is the preclinical status of virtually all efficacy claims — the mechanism is precisely mapped in cells and mice, the human biomarker signal is suggestive, but there are no interventional human data at all [9][11]. Read together, the three peptides trace a spectrum from approved-but-narrow through PK-characterised-but-unevaluated to mechanism-established-but-preclinical.