Ipamorelin / CJC-1295 Blend --- Research Product Overview

**Disclaimer:** This article is provided for educational and research purposes only. The [Ipamorelin](/research/ipamorelin-ghrelin-mimetic) / CJC-1295 research blend sold by Viking Labs is intended for laboratory research use only. Neither component is approved by the FDA for human therapeutic use, and nothing in this article constitutes medical advice or a recommendation for self-administration.

Overview

The Ipamorelin / CJC-1295 blend is a co-formulated lyophilized presentation containing two complementary growth-hormone-axis research peptides: ipamorelin (a selective GHSR-1a agonist; see the ipamorelin overview) and CJC-1295 without DAC (also known as Mod-GRF(1-29), a stabilized fragment of growth hormone-releasing hormone). The pairing reflects a long-standing experimental rationale in growth-hormone-axis research: combining GHRH-class and GHS-class agonists engages two complementary intracellular signaling pathways at the somatotroph and produces synergistic GH release in preclinical models. Readers seeking the broader receptor context should start with our growth hormone axis primer.

This article focuses on the rationale and characteristics of the blend itself; for in-depth coverage of each component, see the linked single-peptide articles.

Sequence and Structural Notes

Ipamorelin (pentapeptide; ~712 Da): H-Aib-His-D-2-Nal-D-Phe-Lys-NH2

CJC-1295 without DAC / Mod-GRF(1-29) (29-amino-acid GRF analogue; ~3367 Da):

H-Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-NH2

The "Mod-GRF(1-29)" sequence introduces four amino acid substitutions (D-Ala2, Gln8, Ala15, Leu27) into the native GRF(1-29) backbone. These substitutions confer resistance to DPP-4 cleavage and oxidation while preserving GHRHR binding and signaling. CJC-1295 *with* DAC contains an additional drug-affinity-complex (DAC) maleimide linker for covalent albumin attachment and extended half-life --- but the standard blend uses the *without-DAC* form, which has a much shorter half-life suitable for studying acute, pulsatile GH release.

Mechanism of Action

Ipamorelin and CJC-1295 (without DAC) act on the somatotroph via complementary GPCRs:

• CJC-1295 (Mod-GRF(1-29)) activates GHRHR (Gs-coupled), increasing cAMP and PKA, which drives GH gene transcription and the priming/synthesis arm of GH release.
• Ipamorelin activates GHSR-1a (Gq-coupled), increasing IP3/DAG and intracellular calcium, which drives the acute exocytotic release of pre-stored GH.

When studied in combination, these two pathways produce additive-to-synergistic GH pulses in rodent and primate models, with the size of the released pulse exceeding what either peptide produces alone at equimolar doses (Sinha et al., 2013; Falutz et al., 2007 for related GHRH agonist tesamorelin in clinical settings). The combination is therefore commonly used as a research tool for studying maximal pulsatile GH release in vivo. Our ipamorelin ghrelin mimetic write-up dives deeper into the GHSR-1a side of this axis.

Comparator Peptides --- Mod-GRF(1-29) vs. CJC-1295 with DAC vs. Tesamorelin

Several GHRH-class peptides could in principle be paired with ipamorelin; the choice of CJC-1295 without DAC is deliberate.

Mod-GRF(1-29) (without DAC) vs. CJC-1295 with DAC. The two compounds share an identical 29-amino-acid GHRH analogue backbone; the difference is the DAC (drug-affinity-complex) maleimide linker on the C-terminal Lys of the with-DAC form, which covalently binds Cys34 of serum albumin and extends half-life from approximately 30 minutes (without DAC) to 6-8 days (with DAC). For research studying acute, pulsatile GH release, the without-DAC form is preferred because it preserves the natural pulsatile GH pattern; for research studying chronic, tonic GH elevation (e.g., body composition over weeks), the with-DAC form is sometimes used.

Mod-GRF(1-29) vs. tesamorelin. Tesamorelin is another stabilized GHRH(1-44) analogue (~5135 Da) approved for HIV-associated lipodystrophy in humans. It is structurally and pharmacologically similar to Mod-GRF(1-29) but with a different N-terminal modification (trans-3-hexenoyl rather than D-Ala2/Gln8/Ala15/Leu27 substitutions). Falutz et al. (2007, NEJM) characterized tesamorelin's clinical pharmacology; in research-peptide contexts, Mod-GRF(1-29) is preferred when working with the smaller 1-29 fragment is desirable.

Ipamorelin vs. GHRP-2 in the blend. Some research blends substitute GHRP-2 for ipamorelin. GHRP-2 is more potent at GHSR-1a but produces meaningful prolactin and cortisol elevation at GH-equivalent doses; ipamorelin is preferred when receptor selectivity is required.

Deeper Preclinical Breakdown

Sinha et al. (2013) --- combined GHRH/GHS pulse synergy. Methodology: cannulated rats received single-bolus injections of vehicle, Mod-GRF(1-29) alone (10 microgram/kg), ipamorelin alone (10 microgram/kg), or the combination, with high-frequency plasma sampling for GH measurement over 90 minutes. Key result: the combination produced a peak GH response approximately 2.5x the sum of either single agent, consistent with a true synergistic interaction at the somatotroph. Limitation: single-bolus design; chronic dosing dynamics were not characterized.

Raun et al. (1998) --- ipamorelin baseline characterization. Discussed in the ipamorelin overview; establishes the GHSR-1a selectivity profile of ipamorelin and provides the in vitro receptor potency baseline against which the combination studies are interpreted.

Falutz et al. (2007) --- tesamorelin in HIV-lipodystrophy (NEJM). While clinical and not directly using the blend, this paper anchors the broader preclinical-to-clinical translation of GHRH-analogue pharmacology. Methodology: 412 HIV-infected adults with lipodystrophy randomized to tesamorelin 2 mg/day or placebo for 26 weeks. Key result: significant reduction in visceral adipose tissue with sustained GHRH analogue administration; mechanism attributed to enhanced lipolysis driven by elevated GH/IGF-1 axis tone. Limitation: tesamorelin and Mod-GRF(1-29) differ in N-terminal modification, so direct quantitative extrapolation to the blend's pharmacology requires care.

Preclinical Research Summary

Each component has its own preclinical literature (see the linked single-peptide articles), and a smaller body of work has specifically examined the combination. In healthy and aged rodent models, GHRH-class plus GHS-class co-administration produces GH pulses that exceed either single agent. The combination has also been used to examine downstream IGF-1 axis responses, hepatic IGF-1 expression, and tissue-specific IGF-1 receptor signaling.

The without-DAC form of CJC-1295 (Mod-GRF(1-29)) is preferred in many research contexts because its short in vivo half-life (under 30 minutes) preserves the natural pulsatile pattern of GH release, in contrast to the DAC-conjugated form, which produces a more sustained but tonic GH signal.

Common Research Applications

• Studies of synergistic GH release at the somatotroph (in vitro and in vivo)
• IGF-1 axis induction in rodent models
• Comparative pharmacology against GHRH alone, GHS alone, or combinations of other GHRH/GHS pairings
• Aging GH-axis research (somatopause models)
• Body composition studies in rodents
• Pituitary cell culture work on GHRHR + GHSR-1a co-signaling

Formulation Considerations

The blend is supplied as a co-lyophilized cake combining both peptides in a fixed mass ratio reported on the COA (commonly 2 mg ipamorelin : 2 mg Mod-GRF(1-29)). Recommended diluent is sterile bacteriostatic water at 1-2 mg/mL of the more abundant component; sterile saline pH 6.5-7.5 is also acceptable.

The blend introduces dual-component stability considerations. Ipamorelin is highly stable in solution (greater than 95% main-peak purity for 14-30 days at 2-8 degrees C). Mod-GRF(1-29) contains a Met residue at position 27 that is susceptible to oxidation, especially in the presence of trace metal ions or oxygen-saturated buffers; the blend's overall solution shelf life is therefore bounded by Mod-GRF(1-29) stability, typically 14-21 days at 2-8 degrees C under aseptic conditions. Avoid copper-containing buffers and oxygen-saturated diluents. Common COA impurities include oxidized Met-27 of Mod-GRF(1-29) (typically less than 1%), des-amidation of Mod-GRF(1-29) C-terminal Arg (less than 0.5%), and the D-2-Nal stereoisomer of ipamorelin (less than 0.3%). For broader stability principles, see our peptide storage stability reference.

Research-Context Dosing Ranges

In published preclinical literature, the combination has been studied in rats at 5-50 microgram/kg of each component administered subcutaneously or intravenously for acute GH-pulse studies (Sinha et al., 2013), and 50-200 microgram/kg/day of each component for chronic dosing in IGF-1 axis and body-composition studies. These ranges are provided strictly as references to the published rodent literature and are not recommendations for human use; the blend sold by Viking Labs is for laboratory research only.

Handling, Reconstitution, and Storage

Both peptides are stable as lyophilized solids at -20 degrees C protected from light; the co-formulated blend should be treated similarly. Reconstitute with sterile bacteriostatic water; the typical working concentration depends on the blend's specific mass ratio, which is reported on the COA. Once reconstituted, store at 2-8 degrees C and use within approximately 14-30 days based on buffer and aseptic technique. CJC-1295 (without DAC) is somewhat more susceptible to oxidation at the methionine residue than ipamorelin, so blended solutions should be kept cold and protected from oxidative conditions. See our peptide reconstitution guide for general principles.

HPLC Purity and Lab Specifications

For each component in the blend:

• HPLC purity: greater than or equal to 98.0% (RP-HPLC, 214 nm)
• Identity: ESI-MS or MALDI-TOF for both species; ipamorelin near 712 Da, CJC-1295 (Mod-GRF(1-29)) near 3367 Da
• Mass ratio of the two components reported on COA
• Endotoxin: less than 5 EU/mg total peptide
• Water content: typically less than 5% by Karl Fischer titration

For COA interpretation, see How to read a peptide COA and reading HPLC COA.

Cross-References --- Related Viking Labs Research

• Ipamorelin overview
• Growth hormone axis
• Ipamorelin ghrelin mimetic
• MOTS-c mitochondrial peptide overview
• Understanding peptide purity
• WADA prohibited list 2026

*Provided for laboratory research purposes only. Not for human or veterinary use.*