CJC-1295
The modified GHRH analog — available with or without DAC, the foundation of the most-studied research GH stack.
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What Is CJC-1295?
CJC-1295 is a synthetic 30-amino-acid analog of growth-hormone-releasing hormone (GHRH 1-29), with four amino-acid substitutions that protect it from the rapid enzymatic breakdown that limits the half-life of native GHRH and sermorelin.
It exists in two distinct forms. CJC-1295 'no-DAC' (also called Modified GRF 1-29) is the bare modified peptide with a half-life of roughly 30 minutes — long enough to produce a clean GH pulse, short enough to mimic physiological release. CJC-1295 'with DAC' has an additional Drug Affinity Complex that bonds to circulating albumin, extending the half-life to roughly 6–8 days and producing a continuous (rather than pulsatile) elevation in baseline GH.
Choice of variant is a major design decision in research protocols. No-DAC is preferred when pulsatility matters (sleep, muscle/fat outcomes, replicating natural rhythm). With-DAC is studied when sustained IGF-1 elevation is the goal (some body-composition and tissue-repair contexts).
History & Discovery
CJC-1295 was developed at ConjuChem, a Montreal-based biotech, in the early 2000s as part of a broader platform exploring drug-affinity-complex (DAC) chemistry for half-life extension. The starting molecule was GHRH 1-29 — the biologically active fragment of native GHRH that had previously been developed as sermorelin.
The medicinal-chemistry team made four amino-acid substitutions (D-Ala²⁸, Gln³⁸, Ala¹⁵, Leu²⁷) to protect the molecule from DPP-4 and trypsin cleavage. This 'modified GRF 1-29' became what is now sold as CJC-1295 without DAC.
The 'with DAC' variant adds a maleimidopropionic acid (MPA) linker that covalently bonds to a free cysteine on circulating serum albumin, extending the half-life from minutes to days — turning a pulsatile GHRH analog into a near-continuous one. This was the original commercial product ConjuChem advanced through phase 1 and phase 2 trials.
ConjuChem discontinued the CJC-1295-with-DAC clinical program in the late 2000s — the molecule produced sustained GH/IGF-1 elevation but raised questions about whether continuous receptor stimulation was physiologically appropriate. The compound entered the research-peptide ecosystem in both forms and is now overwhelmingly used as the no-DAC variant in stacked GH research.
Mechanism of Action
Like all GHRH analogs, CJC-1295 binds the GHRH receptor on somatotroph cells of the anterior pituitary, stimulating endogenous growth hormone release. The body's negative feedback through somatostatin remains intact, distinguishing GHRH-driven GH release from exogenous rhGH administration.
The four amino-acid substitutions in CJC-1295 (D-Ala at position 2, Gln at 8, Ala at 15, Leu at 27) protect the molecule from dipeptidyl peptidase-4 (DPP-4) and other proteases that would otherwise degrade native GHRH within minutes.
The DAC variant adds a maleimidopropionic acid (MPA) group that covalently bonds to a cysteine residue on serum albumin, creating an albumin-CJC-1295 complex that circulates for days — the body's GHRH receptor sees a continuous low-level stimulus rather than a pulse.
Pharmacokinetics
| Molecular weight (no-DAC) | 3,367 Da |
| Molecular weight (with-DAC) | ~3,648 Da (plus albumin conjugate ~70 kDa) |
| Receptor target | GHRH receptor (GHRHR) on pituitary somatotrophs |
| Time to peak GH (no-DAC) | ~15–30 minutes after subcutaneous injection |
| Half-life (no-DAC) | ~30 minutes (functional GH-stimulation window 1–2 hours) |
| Half-life (with-DAC) | Approximately 6–8 days |
| Steady-state IGF-1 rise (with-DAC) | Plateau by week 2 of weekly dosing |
| Feedback preservation | Yes — somatostatin negative feedback intact |
Research Use Cases
Synergistic GH Pulse with GHRP
The most common research configuration: CJC-1295 (no-DAC) stacked with ipamorelin or another GHRP for amplified pulsatile GH release.
Sustained IGF-1 Elevation
CJC-1295 with DAC has been studied for its ability to maintain elevated IGF-1 over multiple days from a single weekly injection.
Body Composition Research
Investigated for lean-mass preservation and adipose reduction, particularly in aging populations with declining endogenous GH secretion.
Recovery and Tissue Repair
Studied in contexts where elevated GH/IGF-1 is hypothesized to support connective-tissue and post-exercise recovery.
Sleep Architecture
No-DAC CJC-1295 dosed in the evening has been studied for its effect on slow-wave sleep restoration in adult research subjects.
GH-Axis Restoration in Somatopause
Used as a research tool to investigate physiological-pattern GH restoration without the supraphysiologic spikes of exogenous rhGH.
Research Dosing Reference
CJC-1295 no-DAC + Ipamorelin (canonical research stack)
The dominant research configuration. Often shorthanded as 'CJC/Ipa 100/100'.
CJC-1295 no-DAC — solo research dosing
Less common than the stacked configuration but used in research isolating GHRH-arm effects.
CJC-1295 with DAC — research dosing
The with-DAC profile is sustained, not pulsatile. Used in research targeting steady IGF-1 elevation rather than physiological pulse restoration.
Body recomposition saturation schedule
Aggressive pulse-frequency schedule used in body-recomposition research contexts.
Stacking & Combinations
CJC-1295 no-DAC + Ipamorelin
The defining stack of modern GH-axis research. CJC-1295 primes somatotrophs to release GH via GHRH-receptor activation; ipamorelin amplifies the magnitude of release through the parallel ghrelin-receptor pathway. Combined GH pulse is roughly 2–4× larger than either compound alone.
CJC-1295 no-DAC + GHRP-2 or hexarelin
Mechanistically equivalent to the ipamorelin pairing — any GHRP partner will produce the synergistic pulse amplification. Less common in modern research because GHRP-2 elevates cortisol/prolactin and hexarelin can desensitize the receptor with chronic use.
CJC-1295 with DAC (standalone)
The with-DAC variant is typically used solo because its sustained-release profile already provides continuous GHRH stimulation — adding a GHRP often produces excessive IGF-1 elevation. Research is sparse compared to the no-DAC stack.
CJC-1295 + Tesamorelin (combined GHRH approach)
Rarely used. Both compounds act on the same receptor — combining them does not increase efficacy beyond the maximal GHRH pulse and adds cost and side-effect burden. Mentioned only to clarify it is not a recommended research configuration.
Side Effect Profile
Common / Mild-to-Moderate
- •Mild flushing or warmth in the first 5–10 minutes after injection
- •Transient lightheadedness shortly after injection
- •Injection-site reactions (redness, itching, mild swelling)
- •Mild water retention in the first 1–2 weeks
- •Vivid dreams / altered sleep architecture (expected GH-axis effect)
- •Numbness or tingling in extremities (dose-related, GH-axis carpal-tunnel-like)
Serious / Less Common
- •Glycemic dysregulation in predisposed subjects, more pronounced with with-DAC due to sustained IGF-1 elevation
- •Hypersensitivity reactions (rare)
- •Theoretical concern: contraindicated in active malignancy (GH/IGF-1 elevation)
- •With-DAC specifically: edema and joint pain are more common at supratherapeutic doses
Side effect profile is dose- and variant-dependent. The no-DAC variant in stacked research dosing has a favorable acute profile. With-DAC is associated with more pronounced metabolic effects due to its continuous-stimulation profile. Standard research practice includes periodic IGF-1 and fasting glucose monitoring.
Storage & Reconstitution
- Lyophilized vials are stored refrigerated at 2–8°C. CJC-1295 is reasonably stable at room temperature for short shipping intervals.
- Reconstitute with bacteriostatic water for injection. For a 5 mg vial, 2 mL is the most common volume — yielding 2.5 mg/mL.
- Inject the BAC water against the vial wall slowly. Swirl gently — never shake — until fully dissolved.
- Once reconstituted, store refrigerated. The no-DAC variant is stable for approximately 30 days for research use; the with-DAC variant has a similar shelf life.
- CJC-1295 and ipamorelin are commonly drawn into the same syringe and injected together. Both are stable at neutral pH in BAC water.
- Use a 31G insulin syringe. For a 2.5 mg/mL concentration, 100 mcg = 0.04 mL = 4 units on a 100-unit insulin syringe.
- Inject subcutaneously, rotating between abdomen and posterior arms. Pre-bed timing aligns with the natural overnight GH pulse.
Key Studies & Trial Data
CJC-1295 with DAC: prolonged GH/IGF-1 elevation in healthy adults
ConjuChem's phase 1 work on CJC-1295 with DAC. Single subcutaneous doses produced detectable GH and IGF-1 elevation lasting 6–11 days — the foundational pharmacokinetic dataset for the with-DAC variant.
Teichman SL, et al. J Clin Endocrinol Metab. 2006;91(3):799–805.
Long-term safety and PK of CJC-1295 with DAC
Multi-dose phase 1 safety and pharmacokinetic study. Weekly subcutaneous CJC-1295 with DAC produced sustained IGF-1 elevation with mild edema and arthralgia at higher doses — establishing the safety envelope used in subsequent research.
Ionescu M, Frohman LA. J Clin Endocrinol Metab. 2006;91(12):4792–4797.
GHRH + GHRP synergy mechanism (foundational)
Foundational study establishing that combined GHRH and GHRP administration produces a GH pulse 2–4× larger than either alone — the mechanistic basis for the modern CJC-1295 + ipamorelin stack.
Bowers CY. J Clin Endocrinol Metab. 1996;81(10):3501–3507 (and subsequent work).
Comparisons & Deep Dives
In-depth articles on Peptide Basics that compare CJC-1295 to related compounds and expand on its mechanism and use.
CJC-1295 Ipamorelin Dosage
The standard research stack — exact dosing, timing, and reconstitution conventions for the combined CJC + ipamorelin protocol.
CJC-1295 vs Sermorelin
Both are GHRH analogs. CJC-1295 has the modifications that extend half-life. Sermorelin is the original 1-29 fragment. Side-by-side comparison.
Ipamorelin vs CJC-1295
Different mechanisms — GHRH analog versus ghrelin mimetic. Why they're complementary rather than competing.
Best Time to Take CJC-1295
Timing matters more than dose for GH-axis peptides. Evening, post-workout, and split-dose schedules examined.
Can You Take CJC-1295 Alone?
Most research uses the GHRH+GHRP stack — but standalone CJC-1295 protocols exist. What the data says about solo use.
Frequently Asked Questions
Where to Source Research-Grade CJC-1295
Base Peptide
Research-grade CJC-1295 (no-DAC and with-DAC variants available) with batch-specific Certificate of Analysis. The standard GHRH partner for the dominant ipamorelin research stack.
Other reputable suppliers known for batch-specific Certificates of Analysis:
Want a deeper, ongoing reference? Peptide Basics maintains a comprehensive resource on CJC-1295 alongside calculators, reconstitution guides, and a database of 60+ research peptides.
Read more on Peptide Basics