CJC-1295 and Ipamorelin: The Growth Hormone Stack Research Guide
CJC-1295 and Ipamorelin are the most commonly researched growth hormone peptide combination — a pairing of a GHRH (growth hormone releasing hormone) analogue and a GHRP (growth hormone releasing peptide) that produce synergistically greater GH release than either compound alone because they act through distinct receptor systems that converge on the same pituitary somatotrophs.
Why pair a GHRH with a GHRP
Endogenous growth hormone is released in pulses from the pituitary gland, governed by two competing signals: GHRH (which stimulates release) and somatostatin (which inhibits release). GHRH analogues like CJC-1295 amplify the stimulatory signal by binding to the GHRH receptor on pituitary somatotrophs, increasing pulse amplitude. GHRPs like Ipamorelin work through a completely different receptor — the ghrelin/GHS-R1a receptor — to trigger GH release pulses and simultaneously suppress somatostatin, removing the brake on GH release while the GHRH presses the accelerator.
The result of combining both mechanisms is synergistic rather than merely additive: the amplitude of each GH pulse increases (from the GHRH signal) while the frequency of inhibition decreases (from the GHRP's somatostatin suppression). Clinical research has confirmed this synergy — combined GHRH and GHRP administration produces GH release significantly greater than the sum of either compound administered alone at equivalent doses.
CJC-1295: GHRH receptor activation
CJC-1295 is a synthetic analogue of GHRH, modified to resist enzymatic degradation in plasma. It is available in two forms: CJC-1295 without DAC (Drug Affinity Complex) and CJC-1295 with DAC. The No DAC version has a half-life of approximately 30 minutes and produces short-acting, pulsatile GH release that more closely mimics the natural GH secretion pattern. The With DAC version has a half-life of approximately 6–8 days due to covalent binding to albumin, producing sustained GH elevation that diverges from the natural pulsatile pattern.
For the CJC-1295/Ipamorelin stack specifically, CJC-1295 No DAC is the most commonly used because its pulsatile release pattern synchronizes well with Ipamorelin's GHRP-mediated pulses. Research protocol: 1–2mg subcutaneous, 5 days on/2 days off schedule, administered fasted. See the CJC-1295 research profile.
Ipamorelin: the cleanest GHRP
Ipamorelin is a pentapeptide GHRP that binds the ghrelin/GHS-R1a receptor to stimulate GH release. Its key characteristic in the research literature is its selectivity: unlike GHRP-2 and GHRP-6 (which also stimulate cortisol and prolactin release), Ipamorelin produces GH release without significant effects on ACTH, cortisol, prolactin, or LH at research doses. This selectivity makes it the preferred GHRP for combination protocols where clean GH stimulation without hormonal side effects is the research objective.
Research protocol: 200–300mcg subcutaneous, up to 3 times daily fasted, 5 days on/2 days off schedule. The combination of CJC-1295 No DAC with Ipamorelin produces synergistic GH release — both compounds are typically administered in the same injection for convenience. See the Ipamorelin research profile.
The 2X Blend and broader GH protocol combinations
The Peptide Hub database contains several pre-formulated growth hormone blend options incorporating these mechanisms. The 2X Tesamorelin/Ipamorelin blend substitutes Tesamorelin (an FDA-approved GHRH analogue for HIV lipodystrophy) for CJC-1295, offering a GHRH with stronger human clinical evidence. The 3X and 4X blends add MGF and GHRP-2 for more comprehensive muscle building and body composition protocols. See the full blend lineup in the database. Use the interactive dose calculators on the dosing guide page for precise unit calculations for any combination.
Timing and administration notes
Fasted administration is critical for GH peptide stacks. Carbohydrate and fat intake both stimulate insulin release, and elevated insulin suppresses GH release — blunting the effect of both the GHRH and GHRP signals. Standard research protocols administer GH stacks either first thing in the morning (at least 30–45 minutes before eating) or immediately before bed (at least 2–3 hours after the last meal). The 5 days on/2 days off schedule is used to maintain pituitary receptor sensitivity and prevent downregulation.
Research sourcing: For research-grade CJC-1295 and Ipamorelin with third-party COA documentation, Peptide Hub recommends Amino Club (partner code: PEPTIDEHUB). Affiliate link — we earn a commission at no cost to you.