Comparison
Ipamorelin and CJC-1295 act through complementary GH axis pathways — ghrelin receptor and GHRH receptor respectively — and form one of the most widely reported peptide stacks in GH axis research.
| Attribute | Ipamorelin | CJC-1295 |
|---|---|---|
| Full name | Ipamorelin | CJC-1295 (with DAC — Drug Affinity Complex) |
| Class | GHRP — ghrelin receptor agonist | Long-acting GHRH analogue |
| Mechanism | Binds ghrelin receptor (GHS-R1a) → discrete GH pulse; does not suppress somatostatin meaningfully | Binds GHRH receptor; DAC modification binds albumin in plasma → half-life extension from minutes to ~6–8 days |
| Half-life | ~2 hours | ~6–8 days (DAC form); ~30 min without DAC (mod GRF 1-29) |
| Commonly reported doses | 100–300 mcg per injection, 1–3× daily | 1–2 mg per week SubQ (DAC form); or mod GRF 1-29 at 100 mcg per dose |
| Routes | SubQ injection | SubQ injection |
| Primary reported use | GH pulse stimulation, sleep quality, body composition | Sustained GH axis elevation, body composition, anti-aging research |
Half-life is the defining practical difference between these two compounds. Ipamorelin has a short ~2-hour half-life, which requires multiple daily injections to maintain GH pulse frequency throughout the day. CJC-1295 with DAC achieves a ~6–8 day half-life through its Drug Affinity Complex modification, which allows the peptide to reversibly bind circulating albumin in plasma — dramatically extending its residence time and requiring only once or twice weekly injection.
The second key difference is mechanism complementarity. Because ipamorelin acts on the ghrelin receptor (GHS-R1a) and CJC-1295 acts on the GHRH receptor, they stimulate GH secretion through independent pathways. When co-administered, these two signals interact at the pituitary to produce a synergistic GH pulse that is substantially larger than either compound can elicit alone. This complementarity is the pharmacological rationale behind why they are one of the most commonly reported research stacks, frequently referred to as "CJC-IPA."
Researchers should note an important naming distinction: "CJC-1295" sometimes refers specifically to the DAC-containing form (long half-life, ~6–8 days, weekly dosing) and sometimes to "modified GRF 1-29" (CJC-1295 without DAC, short half-life of ~30 minutes, dosed similarly to ipamorelin at each injection). These are distinct compounds with meaningfully different dosing requirements and protocols. Vendor labelling is inconsistent on this point, and researchers should confirm which form they are working with before designing a protocol.
CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH). It binds the GHRH receptor on anterior pituitary somatotrophs, activating the adenylyl cyclase–cAMP pathway and stimulating GH synthesis and secretion. The DAC modification — a reactive maleimide group that forms a covalent bond with a lysine residue on circulating albumin — substantially prolongs the active fraction in plasma, enabling the compound's characteristic long half-life.
Ipamorelin is a pentapeptide that acts as a selective agonist of the ghrelin receptor (GHS-R1a). Unlike other GHRPs, ipamorelin is noted for its selectivity: research has investigated it for its potential role in stimulating discrete GH pulses without meaningful elevation of cortisol or prolactin, which distinguishes it from earlier-generation GHRPs such as GHRP-2 and GHRP-6.
When both compounds are administered together, ipamorelin's ghrelin receptor activation and CJC-1295's GHRH receptor activation converge at the pituitary to amplify GH release synergistically. This dual-pathway stimulation is the mechanistic basis for their combination being more effective than either agent alone.
Research has investigated both peptides for their potential role in GH axis support, body composition, recovery, sleep quality, and anti-aging applications. Both compounds are used in the context of GH axis research where exogenous recombinant HGH is not the preferred method.
CJC-1295's longer half-life makes it particularly useful in research protocols where sustained elevation of GHRH signalling is the variable of interest, rather than discrete pulsatile GH release. Anecdotal reports suggest improvement in sleep quality, lean mass, and recovery with both compounds, and these reports are most consistent in the context of the combined stack.
For ipamorelin used alone, commonly reported doses range from 100 to 300 mcg per injection, administered 1–3 times daily. Injections are often timed around sleep (to coincide with the natural nocturnal GH pulse) and/or around fasted training.
For CJC-1295 with DAC used alone, commonly reported doses range from 1 to 2 mg administered once weekly via SubQ injection. The extended half-life means a single injection maintains elevated GHRH signalling across the week.
When the two are stacked together in the commonly reported CJC-IPA protocol, researchers frequently use mod GRF 1-29 (CJC-1295 without DAC) rather than the DAC form for the pulsatile injections. A commonly reported protocol in this context is 100–300 mcg ipamorelin combined with 100 mcg mod GRF 1-29 per injection, dosed 1–3 times daily. This pairing is chosen because mod GRF 1-29 has a short half-life matching ipamorelin's, producing a coordinated GH pulse with each injection.
Both compounds are administered via SubQ injection. Ipamorelin is typically drawn and injected using an insulin syringe into subcutaneous tissue (abdomen or thigh). CJC-1295 with DAC, supplied in lyophilised form, requires reconstitution with bacteriostatic water before use; the reconstituted solution is then drawn and injected SubQ.
Standard peptide handling practices apply: storage of lyophilised peptides at −20°C, reconstituted solutions at 2–8°C, and avoidance of agitation or freeze-thaw cycling of reconstituted product.
Reported side effects in research and anecdotal accounts include water retention, tingling or numbness (particularly in the extremities), fatigue, headache, and injection site reactions. These effects are consistent with GH-axis activity and are commonly associated with GH peptide use generally.
CJC-1295 with DAC may produce more sustained water retention compared to ipamorelin, attributable to its longer half-life and the correspondingly prolonged period of elevated GH/IGF-1 activity. Ipamorelin is specifically noted in research for its low impact on cortisol and prolactin — a meaningful distinction from other GHRPs — which anecdotal accounts suggest contributes to a favourable tolerability profile.
Ipamorelin is commonly used alone by researchers prioritising tight dose control, discrete pulsatile GH stimulation, and low off-target hormonal effects. Its short half-life makes it easy to titrate and limits the duration of any given GH pulse.
CJC-1295 with DAC is commonly chosen when dosing convenience and sustained GHRH axis elevation are the priorities — a single weekly injection makes it one of the most practical GH-axis peptides available. Anecdotal use is high among those who find multiple-daily-injection protocols impractical.
The combination of both compounds (using mod GRF 1-29 in the pulsatile role) is the most commonly reported protocol overall, preferred by researchers and anecdotal users who want the synergistic GH pulse amplitude that neither compound alone can achieve.
Yes — this combination (commonly called CJC-IPA or the CJC-Ipa stack) is one of the most frequently reported GH axis peptide stacks in both research and anecdotal contexts. The synergistic effect on GH secretion arising from simultaneous GHRH receptor and ghrelin receptor activation is a documented pharmacological rationale for combining these two classes of peptide.
For detailed protocol information, dosing context, and timing strategies for the combination, see the CJC-Ipa stack page.
Researchers commonly choose ipamorelin alone when specificity, low off-target hormonal effects, and precise dose control are the primary research priorities. The short half-life enables tight experimental control over GH pulse timing and eliminates any sustained background GHRH stimulation.
Researchers commonly choose CJC-1295 with DAC when dosing convenience and sustained GHRH axis elevation over days are the preferred parameters — typically when the research question involves the cumulative downstream effects of chronically elevated GH/IGF-1 signalling rather than acute pulse dynamics.
The combination is chosen when maximising GH pulse amplitude is the primary research variable. By engaging both the GHRH receptor and ghrelin receptor simultaneously, the combined stack produces a GH release response that exceeds what either compound achieves individually, making it the protocol of choice when GH axis potency is the research objective.
What is the difference between CJC-1295 with DAC and mod GRF 1-29?
CJC-1295 with DAC includes the Drug Affinity Complex modification — a reactive group that covalently binds circulating albumin — giving it a ~6–8 day half-life and enabling once-weekly dosing. Mod GRF 1-29 (also labelled as CJC-1295 without DAC) lacks this modification and has a short ~30-minute half-life, requiring dosing at each injection similarly to ipamorelin. The two compounds produce meaningfully different GH kinetics and require different protocols. Vendor labelling frequently conflates or mislabels them, and researchers should confirm which form they have before use.
Is the ipamorelin/CJC-1295 stack considered safe?
Research and anecdotal accounts describe this as one of the better-tolerated GH axis peptide stacks available. Reported side effects in research and anecdotal accounts are generally mild — most commonly water retention and transient tingling — and ipamorelin in particular is noted for its low impact on cortisol and prolactin. All use remains investigational; individuals should consider this context when evaluating any reported tolerability data.
How long should a CJC-IPA cycle run?
Commonly reported protocols range from 8 to 16 weeks in duration. Cycle length varies based on the specific research objectives, the compounds and doses used, and individual response. Some anecdotal accounts describe longer continuous use, while others incorporate off-cycle periods. There is no established consensus in the research literature on optimal cycle length for this combination.