Dosage in research context

Doses from the trial record

All dose information on this page comes directly from peer-reviewed research publications describing what was administered to study participants under controlled conditions. Published human data covers four subcutaneous dose levels — 30, 60, 90, and 120 micrograms per kilogram — tested in healthy adults aged 21 to 61 in the 2006 Phase 1/2 trial. The two lower doses produced GH and IGF-1 elevation with the cleanest safety profile; the 90 and 120 microgram-per-kilogram cohorts showed more pronounced adverse events. In GHRH-knockout mice, a very different fixed dose (2 micrograms per injection) was used to study growth restoration. No Phase 3 human trial was completed and no approved therapeutic dose exists. Community protocols circulating online are not derived from these published trials and are not reflected here. Nothing on this page is a dose recommendation for human use outside a supervised research setting.

Research context

CJC-1295 is not approved by the FDA for any human therapeutic indication. Phase 2 clinical development was discontinued after Phase 1. All dose information below is drawn from peer-reviewed research publications and describes what was administered to study subjects under controlled trial conditions. None of this constitutes a dose recommendation for human use outside a supervised research setting.

Human Phase 1/2 dose cohorts

Teichman SL et al. (2006, Journal of Clinical Endocrinology and Metabolism, DOI 10.1210/jc.2005-1536) studied four subcutaneous dose levels in healthy adults aged 21–61 years ^[1]:

• 30 μg/kg subcutaneous (single dose): GH elevation 2–10-fold above baseline sustained ≥6 days; no serious adverse events reported ^[1].
• 60 μg/kg subcutaneous (single dose): GH elevation 2–10-fold above baseline sustained ≥6 days; no serious adverse events reported ^[1].
• 90 μg/kg subcutaneous (single dose): GH elevation documented; adverse event profile more pronounced than lower doses ^[1].
• 120 μg/kg subcutaneous (single dose): GH elevation documented; increased adverse events; established the safety margin favoring the lower dose range ^[1].

For the multi-dose phase, repeated subcutaneous dosing in the 30–120 μg/kg range maintained IGF-1 above baseline for up to 28 days ^[2].

Ionescu and Frohman (2006, Journal of Clinical Endocrinology and Metabolism, DOI 10.1210/jc.2006-1702) studied 60 and 90 μg/kg for characterization of pulsatile GH secretion ^[3]. At both doses, basal GH rose 7.5-fold (P < 0.0001), mean GH increased 46% (P < 0.01), and IGF-1 rose 45% (P < 0.001) — all while pulse frequency and pulse characteristics remained intact ^[3].

The Sackmann-Sala et al. proteomics study (2009, Growth Hormone and IGF Research, DOI 10.1016/j.ghir.2009.03.001) used doses of 60–90 μg/kg in 11 healthy young men (mean age 25.2 years) ^[6]. Immunoglobulin fragment intensity linearly correlated with IGF-1 levels (r² = 0.668, P = 0.002), providing biomarker validation of the dose range's GH/IGF-1 axis engagement ^[6].

Rodent model doses

Jetté L et al. (2005, Endocrinology, DOI 10.1210/en.2004-1286) studied CJC-1295 in rats at comparative single subcutaneous doses alongside unmodified hGRF(1-29) ^[4]. Plasma persistence exceeded 72 hours and GH area under the curve was 4-fold greater than the unmodified peptide — establishing the albumin-conjugation-dependent prolongation in vivo ^[4].

Alba M et al. (2006, American Journal of Physiology — Endocrinology and Metabolism, DOI 10.1152/ajpendo.00201.2006) studied GHRH-knockout mice with once-daily subcutaneous CJC-1295 at 2 μg/dose ^[5]. Dosing every 24 hours for 5 weeks fully normalized body weight, body length, femur and tibia development, and body composition, along with increased pituitary GH mRNA. Dosing every 48 or 72 hours produced only partial restoration ^[5]. This study confirmed that GHRH-R is the exclusive mechanism of CJC-1295 activity and established the dose-frequency relationship in a GHRH-null model.

Cui T et al. (2016, Oncotarget, DOI 10.18632/oncotarget.11024) studied related GHRH agonist analogs MR-409 and MR-502 — not CJC-1295 — at 1 μg/day and 10 μg/day topical in C57BL/6 mice for wound-healing outcomes ^[10]. Both doses produced accelerated wound closure (p < 0.01) and human dermal fibroblast proliferation exceeding 50% increase in vitro ^[10]. These findings are cited as class-level mechanistic context; extrapolation to CJC-1295 requires caution.

Half-life data across the GHRH analog series

Half-life data across the GHRH analog series, reported in the primary literature ^[7][2][4]:

• Native GHRH (hGRH 1-44): under 10 minutes. DPP-IV cleaves the Ala-Tyr bond at position 2, rapidly inactivating the peptide.
• Modified GRF 1-29 (CJC-1295 without DAC): approximately 30 minutes. The D-Ala substitution at position 2 blocks the DPP-IV cleavage site; no albumin conjugation means renal filtration proceeds normally.
• CJC-1295 with DAC: 5.8–8.1 days. Effective half-life determined in the Teichman et al. 2006 Phase 1/2 trial. The maleimide-Cys34 thioether bond is stable under physiological conditions ^[8].

Albumin itself has an endogenous half-life of 19–21 days ^[8]. CJC-1295's effective half-life of 5.8–8.1 days is shorter than albumin's, suggesting that peptide dissociation, slow enzymatic degradation of the conjugate, or receptor-mediated clearance accounts for the difference.

The pharmacokinetic-pharmacodynamic decoupling is a distinctive feature: GH pulses remain episodic (PD) even though receptor engagement persists continuously (PK). The receptor is not tonically activated in the way a constant-infusion paradigm would suggest — endogenous somatostatin continues to modulate GH release within the CJC-1295-primed pituitary ^[3][14].

Route considerations

All human Phase 1/2 data for CJC-1295 used the subcutaneous injection route ^[1][2][3][6]. There are no published human data for intravenous, intramuscular, or intranasal administration of CJC-1295.

The rodent studies confirming mechanism (Jetté et al., Alba et al.) also used subcutaneous delivery ^[4][5]. The GHRH agonist wound-healing data from the Schally laboratory used topical delivery in mice and dermal cell culture — a route studied for peripheral tissue effects, not for systemic GH/IGF-1 elevation ^[10]. A GHRH gene-delivery study in aged mice used intramuscular plasmid injection ^[11]; this bears no translational relevance to CJC-1295 pharmacology.

Duration of study varied across published trials: the Teichman et al. single-dose arm assessed pharmacokinetics over 28 days; the multi-dose phase extended further. The GHRH-knockout mouse normalization study ran for 5 weeks with daily dosing. No long-term safety data beyond these study durations exists for CJC-1295 in any species.

Known safety signals from Phase 1

Adverse events reported in the Teichman et al. 2006 trial were dose-dependent and most common at 90–120 μg/kg ^[1]. No serious adverse events were attributed to study drug at 30 or 60 μg/kg. The trial was conducted as a Phase 1 safety study; it was not powered to detect rare or long-term adverse events.

ConjuChem Biotechnologies discontinued Phase 2 development of CJC-1295 following the death of one trial participant, which was evaluated and deemed unrelated to the study drug. No Phase 3 data was generated. No long-term human safety dataset exists.

Theoretical concerns identified in the literature include glucose dysregulation and insulin resistance from sustained GH elevation, potential oncogenic risk (IGF-1 is a mitogen and sustained supraphysiological levels are associated with cancer risk in epidemiological studies), and acromegalic features with chronic supraphysiological dosing ^[18]. These concerns have not been systematically evaluated for CJC-1295 at research doses in controlled human studies.