Ipamorelin vs CJC-1295: GH-Release Peptides Compared
Two growth hormone-releasing peptides with very different mechanisms. Often stacked rather than chosen between — here's why.
Ipamorelin and CJC-1295 are the two most commonly discussed growth-hormone-releasing peptides in the research-chemical market. They're often stacked together in anecdotal protocols aimed at mimicking youthful GH pulses without the adverse effects of exogenous growth hormone injections. Neither is approved for human use anywhere.
Quick comparison
| Ipamorelin | CJC-1295 | |
|---|---|---|
| Class | GHRP (growth hormone-releasing peptide) — ghrelin receptor agonist (GHS-R) | GHRH analog (growth hormone-releasing hormone mimic) |
| Action | Pulses GH by activating the ghrelin receptor on the pituitary | Stimulates GHRH receptor, promoting GH synthesis and release |
| Versions | Single form | With DAC (6–8 day half-life) or without DAC / "modified GRF 1-29" (~30 min) |
| Effect on cortisol/prolactin | Minimal — considered the cleanest GHRP | Minimal |
| Hunger/appetite | Mild — less than GHRP-6 or hexarelin | None directly |
| Human trials | Phase II (post-op ileus) — discontinued | Phase I/II (sleep, GH-deficiency) — discontinued |
| Regulatory status | Not approved. WADA-banned | Not approved. WADA-banned |
How they differ
Ipamorelin and CJC-1295 hit different receptors on the pituitary, which is the core reason they're stacked rather than substituted. Ipamorelin binds the ghrelin receptor (GHS-R1a), the same receptor that hunger hormone ghrelin uses — it triggers a sharp, pulsatile GH release. Unlike older GHRPs, it does not meaningfully raise cortisol or prolactin (👥 human pharmacology studies). CJC-1295 is a GHRH analog: it binds the GHRH receptor and promotes GH synthesis and release through a different signaling cascade. Combining the two in research protocols produces larger GH pulses than either alone — a synergy documented in pharmacology work from Teichman et al. (2006) for CJC-1295 and from various ghrelin-receptor studies for ipamorelin. See the full reviews on Ipamorelin and CJC-1295.
With DAC vs without DAC — what actually changes
CJC-1295 comes in two forms. "With DAC" contains a Drug Affinity Complex — a maleimide group that binds to serum albumin and extends the half-life to roughly 6–8 days. "Without DAC" (also called modified GRF 1-29) has a half-life closer to 30 minutes. The "with DAC" version produces a sustained elevation in GH baseline; the "without DAC" version produces pulses that more closely mimic physiological release. The pulsatile version is generally preferred in research contexts where pulsatile GH signaling matters (liver IGF-1 synthesis responds differently to sustained vs pulsatile GH). Neither has large human safety data.
Evidence depth
Ipamorelin reached Phase IIb for post-operative ileus (Helsinn's trade designation NNC 26-0161) but was discontinued for insufficient efficacy. CJC-1295 with DAC has published pharmacokinetic and pharmacodynamic human data (Teichman et al., 2006, JCEM) showing it raises IGF-1 and GH for days in healthy adults. That is the strongest human GH data of either compound. Neither has published long-term safety or efficacy data for anti-aging, body-composition, or recovery claims — all of those are anecdotal.
Side-effect profile
Both are cleaner than older GHRPs (hexarelin, GHRP-6) with minimal cortisol and prolactin effects. Injection-site reactions, transient tingling or flushing, and occasional water retention are reported in anecdotal use. The main long-term concern for both is elevated IGF-1 — theoretically associated with increased cancer risk and insulin resistance in epidemiological data on acromegaly. Neither has been tested for multi-year human safety.
Which should you choose?
Neither is FDA-approved. Both are WADA-banned. Both are sold as "research use only" with no quality oversight. In research protocols they're typically combined rather than compared — ipamorelin for the pulse, CJC-1295 (usually without DAC) for the tonic GHRH stimulation. For anyone under WADA jurisdiction, both disqualify. For anyone else, the honest answer is that the peer-reviewed human evidence base for either as a standalone therapy is thin.
Sources
- Teichman S.L. et al. "Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults." JCEM, 2006. PubMed 16352683
- Raun K. et al. "Ipamorelin, the first selective growth hormone secretagogue." Eur J Endocrinol, 1998. PubMed 9849822
- Sinha D.K. et al. "Beyond the androgen receptor: the role of growth hormone secretagogues." Asian J Androl, 2020. PubMed 31854335
Related comparisons
- BPC-157 vs TB-500 — healing peptides
- Retatrutide vs Semaglutide — GLP-1 weight loss