CJC-1295 / Ipamorelin

At a Glance

This monograph covers a combination protocol pairing two distinct peptides that act synergistically on the growth hormone axis. Each component is described individually below.

CJC-1295 (no DAC) / Mod GRF 1-29

Ipamorelin

Mechanism of Action

The CJC-1295 / Ipamorelin combination works through complementary mechanisms on the hypothalamic-pituitary growth hormone axis. By stimulating both the GHRH receptor and the ghrelin (GHS) receptor simultaneously, the combination produces a synergistic amplification of pulsatile growth hormone release that exceeds the response to either peptide alone.[2]

CJC-1295 (Mod GRF 1-29)

CJC-1295 without DAC is a modified version of the first 29 amino acids of human growth hormone-releasing hormone (GHRH). Four amino acid substitutions (Ala², Ala⁸, Ala¹⁵, and Leu²⁷ replaced with D-Ala², Gln⁸, Ala¹⁵, and Nle²⁷) confer resistance to dipeptidyl peptidase-IV (DPP-IV) cleavage, extending its functional half-life compared to native GHRH(1-29).[1]

CJC-1295 binds the GHRH receptor (GHRHR) on pituitary somatotroph cells, activating adenylate cyclase and raising intracellular cAMP. This stimulates growth hormone (GH) gene transcription and triggers GH vesicle exocytosis. Crucially, GHRH-mediated GH release remains subject to somatostatin inhibition, preserving the physiological negative feedback loop.[3]

Ipamorelin

Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) that acts as a selective agonist of the growth hormone secretagogue receptor (GHS-R1a), the same receptor targeted by endogenous ghrelin. Unlike earlier GH secretagogues such as GHRP-6 and GHRP-2, ipamorelin is notable for its selectivity: it stimulates GH release without causing significant increases in cortisol, prolactin, or ACTH at therapeutic doses.[4][5]

GHS-R1a activation amplifies the GH pulse initiated by GHRH signaling through a distinct intracellular pathway (phospholipase C / inositol triphosphate / protein kinase C), providing additive and synergistic GH release when administered concurrently with a GHRH analog.[2]

Synergistic Rationale

The combination exploits two complementary mechanisms:

• CJC-1295 initiates the GH pulse by directly stimulating somatotroph cAMP production via the GHRHR pathway.
• Ipamorelin amplifies the pulse amplitude by sensitizing somatotrophs via GHS-R1a signaling and by suppressing hypothalamic somatostatin tone.

This dual-pathway activation produces a GH response approximately 2–3 times greater than either peptide alone, while maintaining the pulsatile secretion pattern that more closely mimics endogenous physiology than exogenous GH administration.[6]

Clinical Evidence

CJC-1295 Human Data

• Teichman et al. (2006): A Phase 1/2 study of CJC-1295 with DAC in healthy adults (n=56) demonstrated dose-dependent increases in GH (up to 10-fold), IGF-1 (1.5–3-fold), and IGFBP-3 after a single subcutaneous injection. Effects persisted for 6–14 days, consistent with the DAC-extended half-life. Notably, adverse events included injection site reactions, transient flushing, and headache.[1]
• Ionescu & Walker (2008): Pharmacokinetic study confirming that CJC-1295 with DAC maintains elevated GH and IGF-1 for 7+ days following a single dose, with peak IGF-1 at day 3–4.[7]

Ipamorelin Human Data

• Raun et al. (1998): The original characterization of ipamorelin as a selective GH secretagogue in rats and swine, demonstrating potent GH release without significant changes in ACTH, cortisol, prolactin, FSH, LH, or TSH levels, distinguishing it from GHRP-6.[4]
• Gobburu et al. (1999): Pharmacokinetic/pharmacodynamic modeling of ipamorelin in human volunteers, establishing the dose-response relationship for GH release with an EC50 of approximately 14 ng/mL.[8]
• Bresciani et al. (2006): Confirmed that ipamorelin stimulates GH in a dose-dependent fashion in human subjects without affecting the cortisol/ACTH axis, reinforcing its selectivity advantage.[9]
• Beck et al. (2014): A Phase 2 study evaluating ipamorelin for postoperative ileus recovery after abdominal surgery found it was safe and well-tolerated, though it did not meet its primary efficacy endpoint for bowel recovery time.[10]

Combination Data

No published controlled human trials have evaluated the specific CJC-1295 (no DAC) + Ipamorelin combination. The synergistic rationale is derived from basic science demonstrating that concurrent GHRH receptor and GHS receptor stimulation produces supra-additive GH release in animal models and in-vitro pituitary cell assays.[2][6] Clinical use is based on extrapolation from individual component data and empirical practitioner experience.

Primary Uses

The CJC-1295/Ipamorelin combination has no FDA-approved indications. The following uses reflect clinical practice patterns and research interest areas:

• Age-related GH decline: Stimulation of endogenous GH production as an alternative to exogenous GH replacement in adults with age-related GH insufficiency (not formal GH deficiency).
• Body composition optimization: Increased lean body mass and reduced adiposity via GH-mediated lipolysis and protein synthesis.
• Recovery and tissue repair: Enhanced recovery from exercise, injury, or surgery through GH-mediated tissue repair pathways.
• Sleep quality: GH secretagogues administered at bedtime may amplify the natural nocturnal GH pulse, which is associated with deeper sleep and improved recovery.
• Skin and connective tissue: Increased collagen synthesis associated with elevated GH/IGF-1 levels.

Contraindications

• Active cancer or history of cancer: Growth hormone promotes cell proliferation and may accelerate the growth of existing malignancies. GH and IGF-1 are implicated in the progression of multiple cancer types including colorectal, breast, and prostate cancer. Any active or recently treated malignancy is an absolute contraindication.[11]
• Pregnancy and breastfeeding: No reproductive safety data exist for this combination. GH-axis perturbation during pregnancy presents unknown fetal risks. Avoid in women who are pregnant, planning pregnancy, or breastfeeding.
• Active pituitary tumors or other intracranial neoplasms: Stimulating GH release from the pituitary is contraindicated in the presence of pituitary adenomas or other CNS tumors that could be affected by altered GH/IGF-1 signaling.
• Hypersensitivity: Known allergy to either CJC-1295 or ipamorelin or any excipient.

Relative Contraindications / Precautions

• Diabetes mellitus: GH antagonizes insulin action and can worsen glycemic control. Patients with type 1 or type 2 diabetes require close glucose monitoring if these peptides are used. Dose adjustments to glucose-lowering medications may be necessary.[12]
• Pre-diabetic / insulin-resistant states: GH-mediated insulin resistance may accelerate progression to diabetes.
• Carpal tunnel syndrome: GH excess can exacerbate carpal tunnel symptoms via soft tissue edema.
• Retinopathy: Elevated IGF-1 may worsen diabetic or other proliferative retinopathy.
• Edematous conditions: GH causes sodium and water retention, which may worsen heart failure, renal insufficiency, or hepatic cirrhosis with edema.

Standard Protocols

Nighttime Pulse Protocol (Most Common)

Both peptides are typically combined in the same syringe and administered as a single subcutaneous injection 30–60 minutes after the last meal. Bedtime dosing is preferred because it coincides with the natural nocturnal GH pulse and avoids interference from food-induced insulin spikes (insulin blunts GH release).

Multi-Dose Protocol (Advanced)

Cycling

Many practitioners recommend cycling GH secretagogue use to avoid tachyphylaxis (receptor desensitization). Common patterns include:

• 5 days on / 2 days off (most common; weekdays on, weekends off)
• 8 – 12 weeks on / 4 weeks off
• Continuous use with periodic IGF-1 monitoring to guide dose adjustments

Stacks & Combinations

In clinical practice, the CJC-1295/Ipamorelin combination is sometimes used alongside other peptides or compounds:

• BPC-157 / TB-500: Added for tissue repair and recovery. These peptides target different pathways (angiogenesis, actin regulation) and do not interact directly with the GH axis.
• Tesamorelin: A GHRH analog approved for HIV-associated lipodystrophy. Some practitioners substitute tesamorelin for CJC-1295 as it is an FDA-approved GHRH analog.
• MK-677 (Ibutamoren): An oral GH secretagogue. Concurrent use with ipamorelin is generally not recommended as both target GHS-R1a and may cause excessive IGF-1 elevation.
• Sermorelin: Another GHRH analog sometimes used interchangeably with CJC-1295 (no DAC). Sermorelin has a shorter half-life (~10 minutes) and may require more frequent dosing.

Preparation & Administration

Reconstitution

Both CJC-1295 and ipamorelin are supplied as lyophilized (freeze-dried) powder in sterile vials. Reconstitution with bacteriostatic water (BAC water) is required before use:

1. Clean the vial stopper with an alcohol swab
2. Draw the desired volume of bacteriostatic water into an insulin syringe (typical: 2 mL per vial)
3. Inject the water slowly along the inside wall of the vial — do not spray directly onto the powder
4. Gently swirl until fully dissolved; do not shake vigorously
5. The solution should be clear and colorless; discard if cloudy or discolored

Example Concentration (CJC-1295, 2 mg vial)

Injection Technique

• Use a 29–31 gauge, 0.5-inch insulin syringe
• Inject subcutaneously into the abdominal fat pad (preferred), thigh, or upper arm
• Rotate injection sites
• Administer on an empty stomach (fasted for at least 2 hours; avoid eating for 30 minutes after injection to prevent insulin-mediated GH blunting)

Side Effects

Common

• Water retention: Mild peripheral edema, particularly in the first 2–4 weeks. Often self-limiting. Related to GH-mediated sodium retention.
• Joint pain / stiffness: Dose-dependent arthralgias, particularly in the hands and wrists. May indicate excessive GH/IGF-1 levels.
• Tingling / numbness: Paresthesias in the extremities, related to GH-mediated fluid retention and possible carpal tunnel compression.
• Headache: Common in the initial days of use; typically transient.
• Increased hunger: Particularly with ipamorelin, which acts on ghrelin receptors. Less pronounced than with GHRP-6.
• Injection site reactions: Transient redness, itching, or minor irritation at the injection site.
• Flushing / warmth: Transient vasodilation and sensation of warmth following injection.

Less Common / Dose-Dependent

• Carpal tunnel syndrome: With prolonged use or supraphysiologic GH elevation.
• Insulin resistance: GH antagonizes insulin action. Monitor fasting glucose and HbA1c with chronic use.[12]
• Increased intracranial pressure: Rare; more commonly associated with exogenous GH therapy than secretagogues.

Drug Interactions

Storage

• Lyophilized (unreconstituted): Refrigerate at 2–8°C (36–46°F). Stable for 12–24 months depending on manufacturer. Can tolerate brief room temperature transit.
• Reconstituted: Refrigerate at 2–8°C. Use within 21 days of reconstitution with bacteriostatic water.
• Do not freeze reconstituted solutions.
• Protect from light (store in original packaging or amber vial).
• Do not use if solution is cloudy, discolored, or contains particulate matter.

Legal Status

• FDA status: Neither CJC-1295 nor ipamorelin is FDA-approved for any human indication. They are classified as research chemicals / investigational peptides.
• Compounding: Some 503A and 503B compounding pharmacies have produced these peptides for clinical use under physician prescription. The FDA has periodically issued guidance regarding GH secretagogues under compounding regulations.
• WADA: Both CJC-1295 and ipamorelin are banned by the World Anti-Doping Agency under category S2 (Peptide Hormones, Growth Factors, Related Substances, and Mimetics).[13]
• DEA scheduling: Not scheduled as a controlled substance in the United States.
• International: Regulatory status varies by jurisdiction. These peptides are prohibited in competitive sports worldwide.

Open Questions

• Combination efficacy data: No published RCTs evaluate the specific CJC-1295 (no DAC) + Ipamorelin combination. Controlled human trials are needed to validate the synergy hypothesis and establish optimal dosing.
• Long-term safety: The long-term consequences of chronic GH secretagogue use on cancer risk, insulin resistance, and cardiovascular health are unknown. Epidemiological data on acromegaly suggests that sustained supraphysiologic GH/IGF-1 levels increase cardiovascular and cancer risk.
• Tachyphylaxis: Whether chronic GHS receptor stimulation leads to meaningful receptor desensitization in humans, and whether cycling protocols prevent this, remains unclear.
• DAC vs. no-DAC: The relative clinical advantages of pulsatile (no DAC) versus sustained (DAC) GH elevation have not been compared in head-to-head trials.
• Optimal IGF-1 targets: The therapeutic window for IGF-1 elevation (benefit vs. risk) in the context of GH secretagogue therapy has not been defined.
• Comparison to exogenous GH: Whether GH secretagogues provide comparable clinical outcomes with a better safety profile than direct GH injection is unresolved.

Bibliography

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2. Bowers CY. GH releasing peptides — structure and kinetics. J Pediatr Endocrinol Metab. 1993;6(1):21-31. doi:10.1515/jpem.1993.6.1.21 · PubMed 8374139
3. Mayo KE, Miller TL, DeAlmeida V, et al. Regulation of the pituitary somatotroph cell by GHRH and its receptor. Recent Prog Horm Res. 2000;55:237-266. PubMed 11036940
4. Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552-561. doi:10.1530/eje.0.1390552 · PubMed 9849822
5. Anderson LL, Jeftinija S, Scanes CG, et al. Physiology of ghrelin and related peptides. Domest Anim Endocrinol. 2005;29(1):111-144. doi:10.1016/j.domaniend.2005.02.033 · PubMed 15876516
6. Bowers CY, Momany FA, Reynolds GA, Hong A. On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone. Endocrinology. 1984;114(5):1537-1545. doi:10.1210/endo-114-5-1537 · PubMed 6425169
7. Ionescu M, Bhatt RS, de la Osa Fresnoza P, et al. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. J Clin Endocrinol Metab. 2006;91(12):4792-4797. doi:10.1210/jc.2006-1702 · PubMed 17018654
8. Gobburu JV, Agersoe H, Jusko WJ, Ynddal L. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharm Res. 1999;16(9):1412-1416. doi:10.1023/A:1018955126402 · PubMed 10496658
9. Bresciani E, Pitsikas N, Tamiazzo L, et al. Feeding behavior during acute and chronic treatment with novel growth hormone secretagogues in aged rats. J Endocrinol Invest. 2006;29(11):RC29-RC32. doi:10.1007/BF03349204 · PubMed 17228970
10. Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Int J Colorectal Dis. 2014;29(12):1527-1534. doi:10.1007/s00384-014-2030-8 · PubMed 25331030
11. Clayton PE, Banerjee I, Murray PG, Renehan AG. Growth hormone, the insulin-like growth factor axis, insulin and cancer risk. Nat Rev Endocrinol. 2011;7(1):11-24. doi:10.1038/nrendo.2010.171 · PubMed 20956999
12. Moller N, Jorgensen JO. Effects of growth hormone on glucose, lipid, and protein metabolism in human subjects. Endocr Rev. 2009;30(2):152-177. doi:10.1210/er.2008-0027 · PubMed 19240267
13. World Anti-Doping Agency (WADA). The 2026 Prohibited List: International Standard. WADA Prohibited List