Frequently asked questions
Answers drawn from peer-reviewed research. Where the literature is silent or uncertain, that is noted.
What is CJC-1295 and how does it differ from native GHRH?
CJC-1295 is a synthetic analog of the first 29 residues of human growth hormone-releasing hormone (hGRH 1-29), extended by one residue bearing the Drug Affinity Complex (DAC) maleimide group. Native GHRH is a 44-amino-acid hypothalamic peptide with a plasma half-life under 10 minutes — degraded rapidly by the enzyme DPP-IV [7]. CJC-1295 makes four amino acid substitutions to resist DPP-IV cleavage and adds the DAC group, which covalently binds Cys34 of circulating serum albumin after injection [8]. The result is an effective half-life of 5.8–8.1 days [2] versus under 10 minutes for the native hormone. Both compounds bind the same receptor (GHRH-R) and trigger the same cAMP/PKA/CREB signaling cascade [13]; the difference is entirely pharmacokinetic.
What is the difference between CJC-1295 with DAC and CJC-1295 without DAC (Modified GRF 1-29)?
The four amino acid substitutions at positions 2, 8, 15, and 27 are present in both variants and confer DPP-IV resistance [7]. The with-DAC variant adds a maleimide-bearing lysine at the C-terminus that reacts with albumin after injection, producing a 67 kDa conjugate with a half-life of 5.8–8.1 days [2][8]. The without-DAC variant (Modified GRF 1-29, Mod GRF 1-29) lacks this group, has a half-life of approximately 30 minutes, and is used in research paradigms where shorter, pulse-mimicking GHRH-R stimulation is the goal [7]. These are pharmacologically distinct compounds despite being structurally related. Secondary sources sometimes conflate them; the distinction matters when comparing published studies.
What does the clinical research show about CJC-1295's effects on GH and IGF-1?
The Teichman et al. 2006 randomized placebo-controlled Phase 1/2 trial is the primary reference [1]. In healthy adults aged 21–61 years, single subcutaneous doses of 30–120 μg/kg produced 2- to 10-fold increases in mean plasma GH concentration, sustained for six or more days. IGF-1 rose 1.5- to 3-fold and remained above baseline for 9–11 days after a single dose [2]. Repeated dosing maintained IGF-1 elevation for up to 28 days [2]. These are Phase 1 data in healthy volunteers; no Phase 3 efficacy trial has been completed.
How long does CJC-1295 stay active in the body?
In the Teichman et al. 2006 human Phase 1/2 trial, the estimated effective half-life was 5.8–8.1 days [2]. This is shorter than albumin's endogenous 19–21-day half-life, suggesting the conjugate degrades or clears faster than albumin itself. In rats, the albumin bioconjugate was detectable in plasma beyond 72 hours after subcutaneous administration and produced a 4-fold increase in GH area under the curve versus unmodified hGRF(1-29) [4]. GH elevation was sustained for six or more days in human subjects after a single injection [1]. IGF-1 elevation persisted for 9–11 days [2].
Does CJC-1295 preserve natural pulsatile GH secretion?
Yes, based on the Ionescu and Frohman 2006 study [3]. At doses of 60 and 90 μg/kg subcutaneous in healthy adults, basal GH levels rose 7.5-fold (P < 0.0001) and overall mean GH increased 46% (P < 0.01), but GH pulse frequency and pulse characteristics remained unchanged. IGF-1 rose 45% (P < 0.001). The interpretation is that CJC-1295 raises the trough (baseline) GH level from which endogenous GHRH-driven pulses occur, rather than replacing or suppressing the pulsatile architecture [17]. This contrasts with exogenous recombinant GH, which blunts endogenous pulsatility via negative feedback.
What are the common research doses studied for CJC-1295 in humans?
The Teichman et al. 2006 Phase 1/2 trial studied 30, 60, 90, and 120 μg/kg administered subcutaneously as single doses [1]. No serious adverse events were attributed to study drug at 30 or 60 μg/kg. Adverse events were more pronounced at 90–120 μg/kg. The 60–90 μg/kg range appears in the most publications because it offered the best-characterized pharmacodynamic profile with an acceptable safety signal in healthy volunteers. No Phase 3 data exists. All of this describes research trial conditions — not recommendations for human use outside such a setting.
Is CJC-1295 on the WADA prohibited list?
Yes. CJC-1295 is listed on the World Anti-Doping Agency's Prohibited List under Section S2 — Peptide Hormones, Growth Factors, Related Substances and Mimetics — both in-competition and out-of-competition. Detection by WADA-accredited laboratories using liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS) is confirmed [15]. Athletes subject to WADA-governed anti-doping programs face violations for its use. Hennige J et al. (2011, Drug Testing and Analysis) confirmed the compound's 29-amino-acid sequence in an illicitly manufactured preparation submitted to Norwegian anti-doping authorities [15].
What is the evidence basis for combining CJC-1295 with ipamorelin in research?
The mechanistic basis is documented in vitro. CJC-1295 activates GHRH-R via the Gαs/cAMP pathway. Ipamorelin activates GHS-R1a (the ghrelin receptor) via the Gαq/calcium pathway — a distinct second messenger route [9]. Cunha and Mayo (2002, Endocrinology, DOI 10.1210/en.2002-220706) demonstrated that simultaneous stimulation of both GHRH-R and GHS-R1a produces synergistic cAMP elevation and GH release greater than the sum of individual stimuli in cells co-expressing both receptors [20]. Ipamorelin is the most selective GH secretagogue of the GHRP class: Raun et al. (1998) demonstrated no significant ACTH or cortisol elevation at doses 200-fold above its effective GH-releasing dose in rats and swine [9]. No published controlled human trial has directly studied the CJC-1295 + ipamorelin combination.
What safety signals emerged in the Phase 1/2 CJC-1295 trials?
The Teichman et al. 2006 trial reported dose-dependent adverse events, most pronounced at 90–120 μg/kg [1]. No serious adverse events were attributed to study drug at 30 or 60 μg/kg. ConjuChem Biotechnologies discontinued Phase 2 development following the death of one trial participant, evaluated as unrelated to study drug. No Phase 3 safety dataset exists. Theoretical concerns in the literature include glucose dysregulation, insulin resistance, potential oncogenic risk from sustained IGF-1 elevation (IGF-1 is mitogenic), and acromegalic features with chronic supraphysiological dosing [18]. None of these theoretical risks have been evaluated in controlled human studies for CJC-1295 specifically.
How does CJC-1295 relate to aging and the somatopause?
Somatopause refers to the progressive decline in GH and IGF-1 secretion that begins in the third decade of life at approximately 14% per decade. A 2026 gerontology review by Mavrych V et al. (Frontiers in Aging, DOI 10.3389/fragi.2026.1790247) cited CJC-1295's Phase 1/2 pharmacodynamic profile as the best-characterized in healthy human adults among long-acting GHRH analogs, while noting that long-term cardiovascular and cancer risks remain incompletely characterized for any GHRH analog [18]. A 2024 study (Tausendfreund et al., Pituitary) tested elderly hospitalized patients (mean age 82 years) with low IGF-1 via GHRH/arginine stimulation and found that 94% (16/17) retained adequate pituitary GH reserve [19]. This suggests the pituitary GHRH-R target remains pharmacologically accessible in most elderly — though peripheral GH resistance rather than pituitary failure may be the dominant mechanism of age-related IGF-1 decline [19].
What is the regulatory status of CJC-1295 in the United States?
CJC-1295 has no FDA-approved indication. It is not on the FDA's 503A bulk substance list, meaning it may not be compounded by pharmacies under Section 503A of the Federal Food, Drug, and Cosmetic Act without specific regulatory clearance. The compound was evaluated for Section 503A Category 2 classification in 2024. The regulatory landscape for compounded peptides in the United States is actively evolving. The compound's legal status for pharmacy-compounding access is unsettled as of publication.
How does GHRH-R signaling work at the molecular level?
GHRH-R is a Gαs-coupled seven-transmembrane receptor. Ligand binding activates adenylyl cyclase, raising intracellular cAMP, which activates protein kinase A (PKA). PKA phosphorylates CREB, driving Pit-1 transcription factor expression and GH gene transcription. PKA also opens voltage-gated calcium channels, triggering direct GH secretory granule exocytosis [13]. Downstream, GH activates hepatic JAK2/STAT5 signaling, producing IGF-1, which drives muscle protein synthesis via PI3K/Akt/mTORC1 [12]. The 2025 Halmos et al. review confirmed extrapituitary GHRH-R expression in cardiac myocytes, lymphocytes, gonads, skin, and kidney [13], with corresponding peripheral biological roles — though human data for CJC-1295 in these tissues is absent.
What extrapituitary effects have been studied for GHRH analog class compounds?
The Schally laboratory's GHRH agonist analogs (MR-409, MR-502) have shown cardioprotection in rat and swine infarction models, islet survival in rodent diabetes models, wound healing via ERK/AKT signaling in human dermal fibroblasts and mouse excision models, and anti-tumor activity in multiple human cancer xenograft models [10][16]. These findings are preclinical and involve analogs developed separately from CJC-1295. The GHRH-R is expressed in peripheral tissues, providing the mechanistic basis for potential extrapituitary effects [13], but direct human studies of CJC-1295 in any of these contexts have not been published.
What is the significance of the 2025 sleep-circuit study for CJC-1295 research?
The Ding X et al. 2025 Cell study mapped the hypothalamic GHRH/somatostatin neuron circuit that governs sleep-stage-specific GH release in mice using fiber photometry and optogenetics [14]. During NREM slow-wave sleep, GHRH neuron activity rises while somatostatin activity falls — producing the large sleep-phase GH pulse. This provides circuit-level mechanistic context for the Ionescu and Frohman 2006 finding [3] that CJC-1295 preserves GH pulse architecture while raising trough GH: the compound primes somatotrophs across sleep cycles, amplifying their response to endogenous GHRH surges without overriding the somatostatin gating mechanism. The study also found that GH itself feeds back to enhance locus coeruleus excitability, promoting wakefulness [14] — a nuance relevant to understanding the interaction between GH axis manipulation and sleep.