CJC-1295 Dosage in the Research Literature

Doses used in published research

CJC-1295 dosage in the research literature reduces to a small set of numbers. Teichman 2006 dosed healthy adult subjects (ages 21-61) at 30, 60, 125, and 250 mcg/kg as single subcutaneous CJC-1295 with DAC injections, plus a separate ascending-dose multi-week arm ^[1]. Alba 2006 dosed GHRH-knockout mice at 2 mcg per injection at 24-, 48-, or 72-hour intervals for five weeks, starting at one week of age ^[3]. These are the published controlled-trial dose ranges for the with-DAC variant.

Observational reports from clinic protocols describe no-DAC variant administration in the range of 100-300 mcg subcutaneously, several times per week; the with-DAC variant in clinic protocols typically appears as a once-weekly injection. These observational protocols are not from controlled trials and do not appear in the peer-reviewed pharmacokinetic literature ^[15]. The FDA Pharmacy Compounding Advisory Committee briefing materials reviewed reconstitution and clinic-protocol patterns in its 2024 docket but did not endorse any dose range ^[13].

CJC-1295 with DAC vs no-DAC

CJC-1295 with DAC vs no-DAC is fundamentally a pharmacokinetic split. DAC (Drug Affinity Complex) is a maleimidopropionyl-lysine linker covalently bound to the C-terminus of the peptide that reacts with free Cys34 of endogenous serum albumin within minutes of subcutaneous injection ^[1]. The peptide then circulates as an albumin conjugate. Plasma half-life: approximately 5.8-8.1 days ^[1].

The no-DAC variant — also known as modified GRF 1-29 — retains the four stabilizing amino-acid substitutions (D-Ala-2, Gln-8, Ala-15, Leu-27) without the linker ^[6]. Plasma half-life: approximately 30 minutes ^[6]. The pharmacodynamic consequence is different GH-release patterns: with-DAC produces sustained mean GH elevation across days; no-DAC produces a pulse closer to native GH physiology, clearing within hours ^[1][6].

Neither variant has FDA-approved status ^[13]. Both are WADA-prohibited under Section S2 ^[10].

CJC-1295 no-DAC (modified GRF 1-29)

CJC-1295 no-DAC is the variant without the albumin-binding linker. The literature also refers to it as modified GRF 1-29, mod GRF 1-29, or tetrasubstituted GRF (1-29). The four amino-acid substitutions (D-Ala-2, Gln-8, Ala-15, Leu-27) confer DPP-IV resistance and extend plasma half-life to approximately 30 minutes versus the sub-10-minute half-life of native GHRH (1-29) ^[6][7]. Without DAC, GH release is pulsatile and short-acting — closer to the physiologic pattern triggered by endogenous GHRH pulses.

CJC-1295 half-life

CJC-1295 half-life is variant-dependent. With DAC, mean plasma half-life is 5.8-8.1 days following a single subcutaneous injection in healthy adults ^[1]. Without DAC, plasma half-life is approximately 30 minutes ^[6]. The native GHRH (1-29) comparison point — sermorelin — runs 11-12 minutes ^[7]. The order-of-magnitude difference between the no-DAC and with-DAC variants is entirely attributable to the DAC linker's covalent albumin binding ^[1].

Plasma persistence and washout

The with-DAC variant remains detectable in plasma for approximately two weeks after a single dose, given the ~8-day half-life ^[1]. Multi-week dosing windows in Teichman 2006 sustained IGF-1 above baseline for up to 28 days ^[1]. The no-DAC variant clears within hours; pharmacodynamic GH elevation is also short ^[6]. The DAC variant's long residence is the practical reason discontinuation is described in clinic monographs as a delayed washout rather than an immediate clearance.

Injection route used in studies

Subcutaneous injection in every published human CJC-1295 pharmacokinetic study, with the abdomen or thigh as the typical injection site in research protocols ^[1]. Alba 2006 used subcutaneous administration in the GHRH-knockout mouse model ^[3]. Some preclinical rodent work used intraperitoneal injection. No published trial has used oral, intranasal, sublingual, or transdermal routes — the peptide's size and structure make oral bioavailability negligible ^[1].

Reconstitution in published protocols

CJC-1295 is supplied as a lyophilized (freeze-dried) powder. Reconstitution in published research and pharmacy monographs uses bacteriostatic water — sterile water containing 0.9% benzyl alcohol as a preservative — as the diluent. Vial concentrations depend on the powder mass: pharmacy monographs and published protocols describe 1-2 mL of bacteriostatic water per 5-mg vial ^[13]. The reconstituted solution is stored refrigerated; stability data in monographs supports approximately 30 days of refrigerated stability.

How long does CJC-1295 stay in your system?

With-DAC variant: detectable in plasma for approximately two weeks after a single dose given the ~8-day half-life ^[1]. No-DAC variant: clears within hours ^[6]. The downstream IGF-1 elevation extends beyond pure peptide clearance because IGF-1 has its own circulating half-life (~16 hours) and the GH-axis activation cascade persists for days after a DAC-variant dose ^[1].

What is the typical CJC-1295 dosage used in research?

Teichman 2006 dosed healthy adult subjects at 30, 60, 125, and 250 mcg/kg as a single subcutaneous injection ^[1]. Subsequent observational reports describe clinic-protocol no-DAC dosing in the 100-300 mcg subcutaneous range, several times per week, and once-weekly with-DAC dosing — none of these clinic protocols are from controlled trials ^[13].

What is the half-life of CJC-1295?

With DAC: approximately 5.8-8.1 days in plasma ^[1]. Without DAC (modified GRF 1-29): approximately 30 minutes ^[6]. The difference is the DAC linker's covalent binding to serum albumin Cys34, which extends residence by roughly two orders of magnitude ^[1].

How is CJC-1295 injected in research protocols?

Subcutaneous injection. The abdomen or thigh is the typical injection site in published human pharmacokinetic studies ^[1]. Subcutaneous administration was also used in the Alba 2006 GHRH-knockout mouse growth-normalization study ^[3].

How is CJC-1295 reconstituted?

Lyophilized powder reconstituted with bacteriostatic water (sterile water with 0.9% benzyl alcohol preservative). Published protocols and pharmacy monographs describe 1-2 mL of bacteriostatic water per 5-mg vial; final concentration scales with vial size and diluent volume ^[13].