What is CJC-1295?
CJC-1295 is a synthetic growth hormone-releasing hormone (GHRH) analog that covalently binds to endogenous albumin after injection, extending its half-life to approximately 8 days and providing sustained stimulation of growth hormone secretion. 1, 2
Mechanism of Action
CJC-1295 is a 30 amino acid peptide (specifically 29 amino acids with a C-terminal amide function) that incorporates a reactive maleimidopropionic acid group at the C-terminus, allowing it to permanently bind to plasma proteins, particularly serum albumin. 1, 3, 4
The albumin conjugation dramatically extends the peptide's duration of action compared to native GHRH, which has an extremely short half-life that limits therapeutic utility. 5, 2
Once bound to albumin, CJC-1295 stimulates growth hormone release from the pituitary gland for more than 6 days in humans after a single administration. 4
Physiological Effects
Growth Hormone Secretion Pattern
CJC-1295 increases trough (basal) GH levels by 7.5-fold while preserving normal pulsatile GH secretion, meaning the natural peaks and valleys of GH release remain intact despite continuous GHRH stimulation. 2
The frequency and magnitude of individual GH secretory pulses are unaltered, but overall mean GH levels increase by 46% due to the marked elevation in baseline GH between pulses. 2
This preserved pulsatility is clinically important because pulsatile GH secretion is considered essential for many of the hormone's physiological effects. 2
IGF-1 Production
CJC-1295 increases serum IGF-1 levels by approximately 45% within one week of a single injection at doses of 60-90 mcg/kg. 2
The IGF-1 increase correlates primarily with the elevation in trough GH levels rather than peak GH levels, implicating the importance of sustained baseline GH elevation for IGF-1 production. 2
In growth hormone deficiency models (GHRH knockout mice), once-daily CJC-1295 administration normalized growth, body composition, and bone length by restoring GH and IGF-1 production. 5
Clinical Formulation
The FDA-approved formulation is tesamorelin (brand name EGRIFTA SV), which is a 44 amino acid GHRH analog with a hexenoyl moiety attached to the N-terminal tyrosine residue. 1
Tesamorelin is supplied as a sterile lyophilized powder containing 2 mg per vial, reconstituted with 0.5 mL sterile water for subcutaneous injection. 1
The molecular weight of tesamorelin (as free base) is 5135.9 Da, and it is prepared as an acetate salt. 1
Regulatory and Safety Considerations
CJC-1295 is classified as a Prohibited Substance under Section S2 of the WADA Prohibited List as a growth hormone releasing factor with performance-enhancing potential. 3
The peptide is being manufactured illicitly and marketed within bodybuilding communities, sometimes before completing clinical trials. 3
Detection in biological samples is challenging because the CJC-1295-protein conjugate has high molecular weight and undefined mass, preventing detection by standard mass spectrometry peptide screening protocols. 4, 6
Specialized immuno-PCR assays can detect CJC-1295 down to 0.8 pg/mL in plasma, though a screening threshold of 50 pg/mL is used in equine testing due to cross-reactivity with endogenous GHRH. 6
Dosing and Duration
In human studies, single doses of 60-90 mcg/kg produced sustained effects for at least one week, with no significant difference in response between these two dose levels. 2
In growth-deficient animal models, once-daily administration of 2 mcg CJC-1295 normalized growth, while dosing every 48-72 hours was less effective despite using the same total dose. 5
The extended half-life eliminates the need for multiple daily injections required with native GHRH, potentially improving therapeutic compliance. 5, 2
Important Caveats
CJC-1295 requires intact pituitary GH secretory capability to be effective, as it stimulates endogenous GH release rather than providing exogenous GH replacement. 2
The peptide increases total pituitary RNA and GH mRNA, suggesting it promotes proliferation of somatotroph cells in the pituitary gland. 5
Long-term safety data in humans remain limited, and the clinical utility is still being evaluated for patients with growth hormone deficiency or other conditions. 2