CJC-1295 (GHRH Analog — DAC & No-DAC)
CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH), available in two formulations: with Drug Affinity Complex (DAC) for extended 6–8 day half-life enabling weekly dosing, and without DAC (Modified GRF 1-29) for pulsatile GH release with 30-minute half-life. Both variants are studied for GH secretagogue activity, body composition, and anti-aging effects, with Grade B+ evidence from human pharmacokinetic and GH-stimulation studies.
Grade: B+
Half-Life (DAC): 6–8 days
Half-Life (no DAC): ~30 min
Route: SubQ
Category: GHRH Analog / GH Secretagogue
DAC vs. No-DAC: Key Comparison
CJC-1295 with DAC
Half-life: 6–8 days Dose: 2 mg per injection Frequency: Weekly or bi-weekly GH pattern: Sustained elevation ("GH bleed") Pro: Convenient dosing Con: Blunts natural GH pulse architecture
CJC-1295 no DAC (Mod GRF 1-29)
Half-life: ~30 minutes Dose: 100–300 mcg per injection Frequency: 2–3x daily GH pattern: Pulsatile (physiologic) Pro: Preserves GH receptor sensitivity Con: Multiple daily injections required
Mechanism of Action
CJC-1295 acts as a GHRH receptor (GHRHR) agonist at the anterior pituitary. Native GHRH is a 44-amino-acid peptide with a very short plasma half-life (~7 minutes) due to DPP-4 cleavage. CJC-1295 incorporates four amino acid substitutions that protect against DPP-4 and endopeptidase degradation, extending its half-life to 30 minutes (no DAC) or ~8 days (DAC variant).
The DAC modification involves a maleimide group on lysine 30 that covalently and irreversibly binds to free cysteine residues on albumin in vivo — essentially piggybacking on albumin's long half-life for sustained circulation. This is the same "drug affinity complex" technology used in some therapeutic antibody conjugates.
Upon GHRHR binding, CJC-1295 stimulates pituitary somatotroph cells via Gs-cAMP-PKA signaling, increasing GH synthesis and secretion. Unlike GHRP/GHSR agonists (e.g., Ipamorelin), GHRH analogs do not directly trigger GH release — they prime the pituitary for enhanced response. This makes the CJC-1295 + Ipamorelin combination mechanistically synergistic: GHRH priming + GHSR triggering produces GH pulses far exceeding either compound alone.
CJC-1295 no DAC + Ipamorelin (Preferred Stack)
Parameter Beginner Intermediate Advanced CJC-1295 (no DAC) 100 mcg 200 mcg 300 mcg Ipamorelin 100 mcg 200 mcg 300 mcg Frequency Once daily Twice daily 2–3x daily Timing Pre-sleep AM fasted + pre-sleep AM + pre-workout + pre-sleep Route SubQ SubQ SubQ Cycle Length 8 weeks 12 weeks 16–24 weeks
CJC-1295 with DAC (standalone)
Parameter Standard Dose 2 mg Frequency Once weekly or every 2 weeks Route SubQ
Side Effects & Safety
Water retention / mild edema (especially with DAC variant) Tingling or numbness in extremities (elevated GH effect) Injection site irritation or redness Fatigue or lethargy at higher doses Potential for elevated IGF-1 (monitor in long-term use) Carpal tunnel syndrome (at chronically elevated GH levels) No hormonal suppression of HPG axis; no PCT required
Contraindications
Active malignancy — GH axis stimulation is contraindicated Acromegaly or existing growth hormone excess Pregnancy and breastfeeding: no safety data
Clinical Evidence
Teichman et al. (2006) — Prolonged Stimulation of Growth Hormone (GH) and IGF-1 by CJC-1295
First clinical PK/PD study of CJC-1295 in 65 healthy adults. Single doses of 30–60 mcg/kg produced 2–10x increases in mean GH levels, lasting for 6 days. IGF-1 elevated 1.3–1.9x. Excellent tolerability.
PMID: 16822960 | DOI: 10.1210/jc.2005-2556
Ionescu and Frohman (2006) — Pulsatile Secretion of Growth Hormone and the Clinical Response to GH-Releasing Hormone
Reviews the physiological importance of pulsatile GH release and provides mechanistic context for preferring no-DAC pulsatile protocols over sustained GH elevation for long-term receptor sensitivity.
PMID: 16549506
Walker et al. (2021) — GH Secretagogues: Mechanism and Applications in Growth Disorders
Comprehensive review of GHRH analogs and GHSR agonists, including CJC-1295 combination data, establishing the mechanistic rationale for GHRH + GHSR synergy in GH pulse amplification.
PMID: 33535079
Stacking Recommendations
Stack Partner Synergy Protocol Note Ipamorelin GHRH priming + GHSR trigger = synergistic GH pulse amplitude Equal mcg doses, inject simultaneously pre-sleep Sermorelin Alternative GHRH analog; lower potency but milder side effect profile May substitute CJC no DAC for milder protocols MK-677 Oral GHSR agonist as daytime complement to injectable CJC+Ipa pre-sleep MK-677 10–25 mg AM + CJC+Ipa pre-sleep
Frequently Asked Questions
What is the difference between CJC-1295 DAC and no DAC?
CJC-1295 with DAC binds albumin for a 6–8 day half-life, creating sustained GH elevation with weekly dosing. CJC-1295 no DAC has a 30-minute half-life, producing discrete GH pulses that more closely mimic natural pulsatile release.
Which is better: CJC-1295 with DAC or without?
For GH pulse preservation, no-DAC stacked with Ipamorelin is generally preferred. DAC produces continuous GH elevation useful for specific goals but may blunt natural pulse architecture over time.
What dose of CJC-1295 is used in research?
No DAC: 100–300 mcg per injection, 2–3 times daily. With DAC: 2 mg once weekly or every 2 weeks.
Should CJC-1295 be taken fasted?
Yes — administration in a fasted state with low insulin levels maximizes GH pulse amplitude. Pre-sleep injection is ideal as it synergizes with natural nocturnal GH secretion.
What does CJC-1295 stack well with?
The CJC-1295 no DAC + Ipamorelin combination is the gold standard GHRH/GHSR stack. CJC-1295 primes the pituitary while Ipamorelin triggers GH release, together amplifying pulse height without substantially increasing cortisol or prolactin.