What was studied — and what was not

What doses were actually studied

CJC-1295 is not approved for any human indication, so there is no labeled dose, no titration schedule, and no clinical practice guideline. This page describes only what was reported in published research — what investigators administered in controlled settings and what they observed.

The human pharmacokinetic study used single subcutaneous doses of 30 to 250 micrograms per kilogram of body weight. At those doses, growth hormone rose two to ten times above baseline and IGF-1 rose one-and-a-half to three times, with effects lasting up to eleven days from a single dose. Multiple-dose cohorts in that trial maintained IGF-1 elevation for up to 28 days.

Animal work used 2 micrograms per dose in GHRH-knockout mice (equivalent to roughly 80 micrograms per kilogram) at 24- to 72-hour intervals. The Phase 2 trial in humans — the only registered efficacy study — was terminated before specific dose data were published. Nothing on this page is prescriptive guidance.

A note on what this page is

CJC-1295 has never been approved by the FDA or any major regulator for human use. There is no labeled dose. There is no titration schedule. There is no clinical-practice guideline.

This page summarizes the doses, routes, and intervals reported in published research — peer-reviewed PK/PD studies in healthy adult Phase 1 cohorts and in animal models. It is descriptive: what investigators administered, what they measured, what they reported. It is not prescriptive: it does not tell a reader what to administer, to whom, at what frequency, or for what purpose. Anyone using CJC-1295 in laboratory research should consult primary sources and applicable institutional and regulatory standards directly, not this page.

The four published studies that contain explicit dose data are summarized below.

Rat pharmacokinetics: Jetté 2005

The foundational pharmacokinetic identification of CJC-1295 was published by Jetté and colleagues in Endocrinology in 2005 ^[1]. The study evaluated several human GRF(1-29)-albumin bioconjugates in rats, characterizing receptor activation on the anterior pituitary and circulating bioactivity over time.

Single subcutaneous bolus doses in the low-μg/kg range produced a four-fold increase in growth hormone area-under-the-curve over two hours relative to unconjugated peptide, with bioactivity remaining detectable beyond 72 hours ^[1]. This established the basic premise of the albumin-bioconjugate platform: a peptide that would otherwise clear in minutes was producing measurable bioactivity for days. The paper named CJC-1295 as the lead candidate among the conjugates evaluated.

GHRH-knockout mouse: Alba 2006

Alba and colleagues administered 2 μg of CJC-1295 per injection to GHRH-knockout mice at three different dosing intervals — 24, 48, and 72 hours — over a five-week treatment period ^[4]. In a 25 g mouse, 2 μg corresponds to approximately 80 μg/kg.

The once-daily (24 h) interval normalized linear growth, body weight, and lean body composition relative to untreated knockout controls. The 48-hour and 72-hour intervals produced partial restoration on the same outcomes. Pituitary somatotroph proliferation and GH mRNA expression both increased with treatment across intervals. No adverse effects on the measured outcomes were reported at the doses studied ^[4].

Human Phase 1: Teichman 2006

The published human dose-ranging data come from a single Phase 1 study by Teichman and colleagues ^[2]. Healthy adults aged 21 to 61 received single subcutaneous injections at one of four dose levels: 30, 60, 125, or 250 μg/kg. Separate multiple-dose cohorts received weekly or biweekly subcutaneous injections for 28 to 49 days.

Reported pharmacodynamic outcomes at single dose were: mean plasma GH elevation of two- to ten-fold above baseline, sustained for at least six days; mean IGF-1 elevation of 1.5- to three-fold above baseline, sustained for nine to eleven days. Multiple-dose cohorts maintained IGF-1 elevation up to 28 days ^[2]. Mean plasma half-life across dose cohorts was estimated at 5.8 to 8.1 days, attributed to covalent albumin bioconjugation via the C-terminal maleimide group ^[3].

The Phase 1 study reported no serious adverse events attributable to study drug. The most commonly reported events were injection-site reactions and transient facial flushing.

Phase 2: terminated before dosing schedules were fully disclosed

The only registered Phase 2 trial of CJC-1295 — NCT00267527, in HIV-associated visceral adiposity, n=192 — was conducted on a weekly subcutaneous dosing schedule ^[7]. The specific μg/kg dose used in Phase 2 was not fully disclosed in the literature before the trial was terminated in October 2006. No primary endpoint publication exists.

Route of administration

Every reviewed human study and the predominant majority of animal studies administered CJC-1295 by subcutaneous injection ^[1][2][4]. Some rodent mechanistic work has used intraperitoneal administration. Intravenous administration appears in early comparator GHRH studies but not as a delivery route for CJC-1295 itself in the published clinical literature.

The practical implication of the DAC bioconjugation mechanism is that delivery must give the peptide time to encounter circulating albumin and form the covalent bond at Cys34 before clearance. Subcutaneous administration provides that sustained-release profile and is the only route in the human PK record.

Half-life: DAC vs non-DAC

Native human GHRH has a plasma half-life of approximately seven minutes. The four amino acid substitutions in the modified GRF (1-29) backbone — D-Ala²/Gln⁸/Ala¹⁵/Leu²⁷ — confer resistance to DPP-4 cleavage, deamidation, and oxidation, extending in-vivo half-life of the non-DAC peptide to approximately 30 minutes while preserving GHRHR binding affinity ^[8].

The DAC variant adds the maleimide-Cys34 bioconjugation step. The reported mean plasma half-life of the bioconjugate in healthy adults is 5.8 to 8.1 days across the dose cohorts of the Teichman Phase 1 study ^[3].

The two compounds — DAC and non-DAC — are often conflated in supplier copy and discussion forums under the umbrella label 'CJC-1295,' but they are pharmacokinetically distinct by roughly two orders of magnitude in plasma persistence.

Stability and handling notes from the research literature

The DAC variant's bioactivity depends on covalent attachment to the free thiol of albumin Cys34, which occurs after subcutaneous administration. Reconstituted peptide is typically stored refrigerated for short-term laboratory use and frozen for longer-term storage; freeze-thaw cycles and elevated temperatures degrade activity, consistent with general peptide handling practice.

The non-DAC variant degrades faster in solution because it lacks the albumin tethering that protects the DAC bioconjugate from peptidase activity. Reported research-context handling for non-DAC modified GRF (1-29) follows the same cold-chain principles but with shorter post-reconstitution working windows.

What the dose record does not establish

The published dose record establishes single-dose and short-course pharmacokinetic and pharmacodynamic parameters in healthy adult Phase 1 cohorts (n at the low double digits per dose level) and in animal models. It does not establish a safe long-term human dose for any indication, a comparative effectiveness benchmark, an appropriate dose for any clinical endpoint, or any dose recommendation outside the controlled research settings in which those doses were administered.

The Phase 2 program that would have generated comparative efficacy data at a defined dose was terminated before it could publish those data ^[7].