CJC-1295: How an Albumin-Binding Tag Extended a GHRH Analog, and What FDA and WADA Say

CJC-1295 is best understood as a chemistry fix for a timing problem. Native growth hormone-releasing factor is short-lived in circulation, and the team at ConjuChem set out to make a version that would bioconjugate to serum albumin and so stay in plasma longer (Jetté 2005). This Vial Post explainer walks through how that design works, what the three papers most often cited for CJC-1295 actually measured, and how FDA and WADA classify the compound today.

Nothing below is guidance on use in people or animals. The Vial Post covers CJC-1295 strictly as a subject of laboratory and literature research.

Quick Facts

• What it is: a tetrasubstituted form of human GH-releasing factor (hGRF) 1-29 with an added N-epsilon-3-maleimidopropionamide derivative of lysine at the C terminus (Jetté 2005).
• Why the maleimide matters: it is a reactive group placed so the peptide can bioconjugate to the free thiol on Cys34 of serum albumin (Jetté 2005).
• PubChem record: CID 91971820 lists the formula C165H269N47O46, a molecular weight of 3647.2 g/mol and CAS number 446262-90-4 (PubChem).
• Reported half-life in the first human study: an estimated 5.8 to 8.1 days (Teichman 2006).
• Regulatory note: FDA lists CJC-1295 among bulk substances whose compounding nominations were withdrawn after being placed in category 2 (FDA bulk substances page).
• Sport: WADA's 2026 Prohibited List names CJC-1295 as a GHRH analogue under section S2.2.4 (WADA 2026).

The Design Problem: Making a Short Peptide Stick Around

The 2005 Endocrinology paper describes the strategy in one line: attaching a peptide to the free thiol on Cys34 of albumin, via a strategically placed reactive group, is a useful tool to extend plasma half-life (Jetté 2005). The authors built three maleimido derivatives of hGRF(1-29) and tested them in sequence:

1. Ex vivo conjugates. All three were bioconjugated to human serum albumin outside the body. Each conjugate showed enhanced in vitro stability against the enzyme dipeptidylpeptidase-IV and stayed bioactive in a GH secretion assay in cultured rat anterior pituitary cells. 2. Rat screening. Given to male Sprague Dawley rats, the best compound, CJC-1295, produced a 4-fold larger GH area under the curve over two hours than unmodified hGRF(1-29). 3. Tracking the albumin complex. In rat plasma, CJC-1295 was still present beyond 72 hours. A Western blot found a CJC-1295 immunoreactive species on the serum albumin band from 15 minutes onward, still in circulation beyond 24 hours.

A GRF(1-29) analog without this albumin-reactive lysine is a different molecule; see our separate CJC-1295 (no DAC) explainer.

What the Human Pharmacology Papers Measured

Two 2006 papers report the human pharmacology. Read closely, they are pharmacology studies, not evidence of any benefit.

Teichman 2006 (Journal of Clinical Endocrinology & Metabolism). - Design: two randomized, placebo-controlled, double-blind, ascending-dose trials lasting 28 and 49 days, run at two investigational sites in healthy subjects aged 21 to 61. - What was measured: peak concentrations and area under the curve for GH and IGF-I, plus standard pharmacokinetic parameters for CJC-1295. - Headline pharmacokinetic finding: an estimated half-life of 5.8 to 8.1 days. - Who ran it: the first author is listed with WinPharm Associates; the co-authors' affiliations are given in the paper.

Ionescu and Frohman 2006 (same journal). - Question: whether GH release stays pulsatile when the GHRH signal is continuous. The paper describes CJC-1295 as binding permanently to endogenous albumin after injection, with a half-life of about 8 days. - Design: 20-minute blood sampling over an overnight 12-hour period in healthy men aged 20 to 40, before and one week after a single administration. - Finding on pulsatility: the frequency and magnitude of GH secretory pulses were unaltered, while basal (trough) GH levels rose markedly.

Neither paper is guidance, and The Vial Post does not report the administered amounts.

Where It Stands With FDA and WADA

• FDA compounding review. CJC-1295 appears in FDA's table of bulk drug substances "nominated but withdrawn," a list of substances previously in category 2 of the interim policies whose nominations were withdrawn. FDA's stated concerns are possible immunogenicity for certain routes of administration and complexities with peptide-related impurities and API characterization. The agency also says it has identified serious adverse events associated with CJC-1295, including increased heart rate and a systemic vasodilatory reaction, and that available clinical data are limited (FDA bulk substances page).
• Anti-doping. WADA's 2026 list, in effect from 1 January 2026, places CJC-1295 under S2.2.4 growth hormone releasing factors, a class prohibited at all times, in and out of competition (WADA 2026).

For the wider policy backdrop, read our report on the interim compounding policy.

Questions Readers Ask

What makes CJC-1295 long-acting? A C-terminal lysine carrying a maleimidopropionamide group lets the peptide bioconjugate to the Cys34 thiol of serum albumin (Jetté 2005); Ionescu and Frohman describe it as binding permanently to albumin after injection (Ionescu 2006).

How long does CJC-1295 last? The first human study estimated a half-life of 5.8 to 8.1 days (Teichman 2006). Ionescu and Frohman cite about 8 days (Ionescu 2006).

Is CJC-1295 an approved drug? FDA's compounding page lists it among withdrawn category 2 nominations and notes limited clinical data (FDA bulk substances page). WADA lists it as a prohibited GHRH analogue (WADA 2026).

A Note for the Lab

Researchers comparing material from different sources should first confirm which molecule is in the vial: the albumin-binding form described above, or the unconjugated GRF(1-29) analog. A batch Certificate of Analysis with mass spectrometry identity data is the place to check. For background, see how the DAC linker changes CJC-1295.

For research and educational use only. This article is not medical advice and does not describe dosing or human use.