CJC-1295 vs Hexarelin.

CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH), based on the first 29 amino acids of human GHRH (GRF 1-29) with several amino-acid substitutions that resist enzymatic degradation. The name is used for two distinct molecules: "CJC-1295 with DAC," which carries a Drug Affinity Complex (a maleimidoproprionic acid linker) that covalently binds to circulating albumin to dramatically prolong its action; and "CJC-1295 without DAC" (often sold as "modified GRF 1-29" or "Mod GRF 1-29"), which lacks the albumin-binding linker. It was originally developed by the Canadian biotech company ConjuChem as an investigational therapeutic.

Hexarelin (examorelin) is a synthetic hexapeptide growth hormone secretagogue (GHS), structurally derived from the GHRP-6 family of growth hormone-releasing peptides. It is an investigational compound that was studied in the 1990s and 2000s as a potential agent for probing and stimulating growth hormone secretion and, separately, for direct effects on the heart. It is not an approved drug.

As a GHRH analog, CJC-1295 binds the GHRH receptor on somatotroph cells of the anterior pituitary, activating Gs-protein/cAMP/PKA signaling to stimulate synthesis and pulsatile release of endogenous growth hormone (GH), which in turn raises hepatic insulin-like growth factor 1 (IGF-1). The four substitutions in the GRF(1-29) backbone (notably at the position-2 alanine that is the dipeptidyl peptidase-IV cleavage site) protect the peptide from rapid breakdown, extending the half-life of the non-DAC form to roughly 30 minutes versus minutes for native GHRH. In the DAC version, the maleimide linker forms a covalent bond with cysteine-34 of serum albumin, creating a long-circulating depot; because it raises GH in a more sustained rather than sharply pulsatile manner, it is described as increasing trough and mean GH while largely preserving the body's own pulse pattern.

Hexarelin acts as an agonist at the growth hormone secretagogue receptor type 1a (GHS-R1a), the same pituitary/hypothalamic receptor activated by the natural hormone ghrelin. Receptor binding engages Gq/11-phospholipase C signaling, mobilizing intracellular calcium in pituitary somatotrophs and triggering pulsatile growth hormone release; this pathway is distinct from and synergistic with GHRH, and also opposes somatostatin tone. Hexarelin additionally binds CD36, a scavenger receptor expressed in cardiac and vascular tissue, which is the proposed basis for GH-independent cardiovascular effects observed in animal models. Because it is a non-selective secretagogue, it also stimulates ACTH/cortisol and prolactin release to a greater degree than more selective agents.

The principal human evidence is a single 2006 Phase 1 study in healthy adults by Teichman et al. (J Clin Endocrinol Metab, PMID 16352683), which reported that one subcutaneous dose of CJC-1295 with DAC produced dose-dependent increases in mean plasma GH of roughly 2- to 10-fold for 6 days or more and IGF-1 increases of about 1.5- to 3-fold for 9-11 days, with an estimated half-life of 5.8-8.1 days and IGF-1 staying above baseline up to 28 days after repeated dosing. ConjuChem advanced the DAC compound into a Phase 2 trial in HIV-associated visceral obesity (ClinicalTrials.gov NCT00267527), but that 12-week trial was terminated in 2006. Beyond these, robust controlled human efficacy and long-term safety data are essentially absent; there are no large or long-term trials, no published outcomes for the non-DAC "modified GRF 1-29" form in humans, and much of the mechanistic rationale rests on GHRH-class pharmacology rather than direct trials of this molecule. Claims about body composition, recovery, or anti-aging benefit are not supported by published controlled human outcome data.

Human data exist but are limited to small, short-term, acute physiology studies rather than outcome trials. Acute intravenous hexarelin reliably raised serum growth hormone in healthy volunteers and was compared head-to-head with GH in a controlled human study (Imbimbo/Ghigo group, J Endocrinol Invest 1999, PMID 10342360). Separate small studies reported short-lasting increases in left ventricular ejection fraction and cardiac output in normal subjects, GH-deficient patients, and dilated-cardiomyopathy patients, effects that appeared GH-independent (Bisi/Broglio et al., Endocrine 2001, PMID 11322491). A chronic-administration study found that GH responses desensitized over weeks and characterized effects on the pituitary-adrenal axis and prolactin (Clin Endocrinol 1999, PMID 10341859). Most cardioprotection evidence (CD36-mediated ischemia/reperfusion protection, IL-1 signaling) is preclinical and rodent-based (e.g., Int Heart J 2017, PMID 28321024; review J Geriatr Cardiol 2014, PMID 25278975); none of this advanced to a successful human cardiac outcome trial, and clinical development was discontinued.

In the short Phase 1 work, CJC-1295 with DAC was described as generally well tolerated, with the kinds of effects expected from GHRH-class agents (e.g., injection-site reactions, flushing, headache); however, this reflects small numbers and short follow-up. The Phase 2 HIV trial (NCT00267527) was terminated in 2006, and a participant death during the program drew scrutiny, though available reporting attributed that death to pre-existing coronary disease rather than establishing causation by the drug; the episode underscores how thin the safety record is. Sustained elevation of GH/IGF-1 carries class-level theoretical concerns familiar from growth-hormone pharmacology, including fluid retention, joint/muscle pain, insulin resistance and elevated blood glucose, and a theoretical concern about promoting growth of existing malignancy; long-term safety in humans is simply unknown. Much material sold as "CJC-1295" online is from unregulated sources with no purity, sterility, or identity guarantees, adding contamination and mislabeling risks.

Documented effects in human studies include hexarelin's lack of GH selectivity: it raises cortisol, ACTH, and prolactin alongside growth hormone, so it does not produce a clean GH signal. A well-described limitation is rapid tachyphylaxis/desensitization, with attenuated GH responses on repeated or continuous dosing demonstrated both in vitro (second-messenger level) and over weeks of human administration. Long-term safety in humans is essentially unknown because no large or extended trials were completed; chronic GHS-driven IGF-1 elevation raises theoretical concerns common to this class (fluid retention, insulin sensitivity changes, and the general caution that growth-promoting signaling could be undesirable in the setting of malignancy), but these are not established for hexarelin specifically. There is no established safety profile for non-clinical/self-administered use.

CJC-1295 (with or without DAC) has never been approved by the FDA or any major regulatory agency for any indication and remains an investigational compound that did not complete clinical development. It is not an approved medicine; it is sold only as a "research chemical," and GHRH analogs/GH secretagogues of this type are prohibited in sport by the World Anti-Doping Agency.

Hexarelin is investigational and has never received FDA or EMA marketing approval; its clinical development was discontinued. It is prohibited in sport at all times by WADA as a growth hormone secretagogue / GH-releasing peptide under category S2 of the Prohibited List, and it is generally sold only as a research-use-only chemical.