CJC-1295 Dosage in the Research Literature
Published dosing for CJC-1295 with DAC ranged from 30–125 μg/kg SC in human ascending-dose trials; the no-DAC form (Mod GRF 1-29), with its ~30-minute half-life, requires multiple daily pulses in research protocols. This page covers what was administered, to which species, at which dose, in published studies.
All dosing described on this page is research-context framing: what was administered in a published study. This site makes no human dosing recommendations. CJC-1295 is not FDA-approved for any indication.
Research Doses Documented in the Literature
CJC-1295 dosage in published human trials was administered subcutaneously at 30, 60, 90, and 125 μg/kg in the ascending-dose Teichman 2006 trial[1] and at 60 and 90 μg/kg in the Ionescu and Frohman 2006 GH-pulsatility sub-study.[2] These are the only peer-reviewed human pharmacokinetic datasets for CJC-1295 with DAC. No published human pharmacokinetic study for CJC-1295 without DAC (Mod GRF 1-29) exists.
In the rodent literature, GHRH-knockout mice received 2 μg/day SC once-daily for five weeks in the Alba 2006 normalization study.[4] Ipamorelin, studied alongside CJC-1295 in stacking rationale research, was administered at 0.5–100 μg/kg SC, two to three times daily in rat bone and catabolism models.[10][11]
Half-Life: With DAC vs Without DAC
CJC-1295 without DAC has a plasma half-life of approximately 30 minutes, derived from DPP-IV resistance structural data; the Jetté et al. 2005 pharmacological characterization study is the primary source for this estimate.[3] CJC-1295 with DAC has a terminal half-life of 5.8–8.1 days, measured directly in the Teichman 2006 human ascending-dose trial.[1]
The difference — approximately 250-fold — arises entirely from the DAC albumin-binding mechanism: after SC injection, the maleimide-Lys C-terminal extension covalently binds the free thiol of Cys34 on circulating serum albumin, producing a ~70 kDa complex that is too large for renal filtration and is shielded from proteolytic inactivation. Sermorelin, for comparison, has a half-life of ~10–12 minutes.[15]
CJC-1295 with DAC vs Without DAC: Dosing Differences
The with-DAC and without-DAC forms require fundamentally different dosing architectures in research protocols.
| Form | Half-Life | Injection Frequency (Research) | GH Profile |
|---|---|---|---|
| CJC-1295 with DAC | 5.8–8.1 days | Once-weekly or biweekly | Tonic GH elevation |
| CJC-1295 no DAC (Mod GRF 1-29) | ~30 minutes | Multiple daily injections | Discrete pulsatile GH response |
With DAC — half-life 5.8–8.1 days — the Teichman 2006 study used single-injection ascending-dose designs; subsequent research has studied once-weekly or biweekly injection schedules.[1] The sustained tonic GH elevation means a single injection covers a week of measurable hormonal response.
Without DAC (Mod GRF 1-29) — half-life ~30 minutes — has a short activity window requiring multiple daily pulses in research designs to maintain sustained GH stimulation. Each injection produces a discrete GH pulse that decays within approximately one to two hours. This preserves physiologic pulsatility more closely than the tonic with-DAC profile.[14]
Injection Frequency in Research Protocols
CJC-1295 with DAC was studied at single-injection and once-weekly or biweekly SC injection schedules due to its 6–8 day half-life.[1][2] The no-DAC form (Mod GRF 1-29), with its ~30-minute half-life, requires multiple daily pulses in research protocols that aim to maintain continuous GH stimulation. Published clinical studies run from single-dose PK characterization to 49-day continuous administration.
Cycling Protocols in the Literature
Published research protocols vary in cycle design. Some studies use continuous administration for 12 or more weeks; others use 5-days-on / 2-days-off dosing schedules to model physiologic pulsatility rhythms. The Teichman 2006 trial ran to 49 days; the GHRH-knockout mouse study by Alba et al. used five continuous weeks of once-daily dosing.[1][4]
No peer-reviewed comparative cycling data exists in humans. The cycling question — how long to dose, how long to rest, whether rest is necessary — remains open in the published record.
Fasted vs Fed Administration
Insulin and elevated blood glucose blunt pituitary GH response via somatostatin-mediated suppression. Administering GHRH analogs in a fasted state is a recurring design variable in research studies examining GH pulse amplitude. This rationale is documented in both the Jetté 2005 and Teichman 2006 CJC-1295 papers.[1][3]
Reconstitution and Storage
Reconstituted peptide stability data for CJC-1295 in bacteriostatic water is not directly published for this compound. General peptide stability literature supports refrigerated storage at 2–8°C for up to approximately 30 days post-reconstitution for peptides of comparable size and structure. Freeze-thaw cycles risk peptide bond degradation and are generally avoided in laboratory protocols.