The Muscle Growth Stack: CJC-1295 + Ipamorelin + IGF-1 LR3
Last updated: 2026-02-20
The CJC-1295, Ipamorelin, and IGF-1 LR3 muscle growth stack is designed for researchers interested in the anabolic potential of peptide-mediated growth factor elevation. This three-compound protocol combines the growth hormone-elevating synergy of CJC-1295 and Ipamorelin with the direct anabolic signaling of IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1).
CJC-1295 and Ipamorelin stimulate the pituitary to produce growth hormone through complementary pathways (GHRH and ghrelin receptors, respectively), which in turn elevates circulating IGF-1 through hepatic conversion. IGF-1 LR3 adds a direct layer of anabolic stimulation by activating the IGF-1 receptor on muscle cells with a significantly extended half-life compared to native IGF-1.[1]
This guide covers the scientific basis for each compound, the synergy rationale, a complete dosing protocol with timing, expected timeline of effects, safety considerations, and answers to frequently asked questions grounded in the available research.
Compounds in This Stack
CJC-1295
GHRH analog for sustained GH and IGF-1 elevation
CJC-1295 (without DAC / Mod GRF 1-29) is a modified growth hormone-releasing hormone analog that stimulates pituitary GH production through the GHRH receptor. In this muscle growth stack, CJC-1295 provides the foundational GH elevation that drives systemic IGF-1 production, muscle protein synthesis, fat oxidation, and connective tissue repair.[2]
| Parameter | Detail |
|---|---|
| Research Dosage | 100–200 mcg per injection |
| Frequency | 2–3x daily (with Ipamorelin) |
| Administration | Subcutaneous, fasted state |
| Half-Life | ~30 minutes (no DAC version) |
Ipamorelin
Selective GH secretagogue for GH pulse amplification
Ipamorelin is the selective ghrelin receptor agonist that amplifies each GH pulse initiated by CJC-1295. Its inclusion is critical for maximizing the GH response while maintaining a clean hormonal profile—ipamorelin does not significantly raise cortisol, prolactin, or appetite, unlike older secretagogues.[3]
| Parameter | Detail |
|---|---|
| Research Dosage | 100–300 mcg per injection |
| Frequency | 2–3x daily (with CJC-1295) |
| Administration | Subcutaneous, fasted state, same syringe as CJC-1295 |
| Selectivity | No significant cortisol, prolactin, or appetite effects |
IGF-1 LR3
Direct anabolic growth factor for muscle cell proliferation
IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a modified version of IGF-1 with an extended half-life of 20–30 hours (compared to ~15 minutes for native IGF-1). The modification involves replacing glutamic acid at position 3 with arginine and adding 13 additional amino acids to the N-terminus. This structural change dramatically reduces binding to IGF-binding proteins (IGFBPs), allowing more free IGF-1 to reach target tissues.[1]
Mechanism in this stack: IGF-1 LR3 activates the IGF-1 receptor (IGF-1R) on skeletal muscle cells, triggering the PI3K/Akt/mTOR signaling cascade that drives muscle protein synthesis and satellite cell activation. It promotes both muscle cell hypertrophy (growth of existing fibers) and hyperplasia (formation of new muscle fibers)—a distinction from most anabolic pathways which only promote hypertrophy.
| Parameter | Detail |
|---|---|
| Research Dosage | 20–80 mcg per day |
| Frequency | Once daily or split into bilateral injections |
| Administration | Intramuscular (into trained muscle groups) or subcutaneous |
| Half-Life | 20–30 hours (vs ~15 min for native IGF-1) |
| Cycle Duration | 4–6 weeks on, 4 weeks off |
How They Work Together
This three-compound stack creates a layered approach to growth factor optimization that targets muscle growth from multiple angles simultaneously.
Layer 1: Endogenous GH Elevation (CJC-1295 + Ipamorelin)
The CJC-1295 and Ipamorelin combination stimulates the pituitary gland to produce and release growth hormone through dual-receptor activation. This elevates systemic GH, which travels to the liver and triggers the production of endogenous IGF-1. The elevated GH also directly promotes fat oxidation and has anabolic effects on connective tissue (tendons, ligaments, cartilage).[2]
Layer 2: Exogenous IGF-1 Amplification (IGF-1 LR3)
While the CJC-1295/Ipamorelin combination raises IGF-1 levels through the natural GH→IGF-1 axis, IGF-1 LR3 provides direct, additional IGF-1 receptor activation beyond what the endogenous system can produce. Because IGF-1 LR3 has reduced IGFBP binding, it circulates as free (bioavailable) IGF-1 for 20–30 hours, providing sustained anabolic signaling that complements the pulsatile GH pattern from the secretagogue pair.[1]
Complementary Anabolic Mechanisms
- GH-mediated effects (CJC-1295 + Ipamorelin): Fat oxidation, collagen synthesis, connective tissue repair, endogenous IGF-1 production, improved sleep quality and recovery
- Direct IGF-1R activation (IGF-1 LR3): Muscle protein synthesis via mTOR, satellite cell activation, potential muscle fiber hyperplasia, nutrient partitioning toward muscle tissue
Recovery Enhancement
The GH component improves recovery through enhanced sleep quality, connective tissue repair, and overall anabolic support. IGF-1 LR3 supports muscle-specific recovery by promoting satellite cell proliferation, which are the precursor cells responsible for muscle fiber repair and growth. This comprehensive recovery support allows for higher training volumes and frequencies.
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Protocol & Dosage Schedule
Dosage Schedule
| Compound | Dose | Frequency | Timing | Cycle |
|---|---|---|---|---|
| CJC-1295 (no DAC) | 100–200 mcg | 2–3x daily | Fasted: morning + bedtime (± post-workout) | 12–16 weeks |
| Ipamorelin | 100–300 mcg | 2–3x daily | Same timing as CJC-1295 (same syringe) | 12–16 weeks |
| IGF-1 LR3 | 20–80 mcg | 1x daily (training days) | Post-workout IM or subQ | 4–6 weeks on / 4 weeks off |
Cycle Length
CJC-1295 and Ipamorelin are typically run for 12–16 weeks continuously, while IGF-1 LR3 is cycled in shorter 4–6 week blocks with 4-week breaks to prevent IGF-1 receptor desensitization. A common approach: start CJC-1295/Ipamorelin for the full 12–16 weeks, and introduce IGF-1 LR3 during weeks 3–8 (after GH levels have established a baseline elevation). A second IGF-1 LR3 block can be run during weeks 11–16 if desired.
Timing & Administration
CJC-1295 + Ipamorelin timing: Administer on an empty stomach (2+ hours post-meal). Most effective times are upon waking (fasted) and before bed (to amplify the nocturnal GH surge). A third dose post-workout (if 3x daily) further leverages exercise-induced GH release. Both peptides can be drawn into the same syringe.
IGF-1 LR3 timing: Administer post-workout via intramuscular injection into the trained muscle group(s) for localized effects, or subcutaneously for systemic distribution. Post-workout timing is preferred because exercise sensitizes muscle tissue to IGF-1 receptor activation and creates an anabolic window.
Sample training day schedule:
- 6:00 AM – Wake up, inject CJC-1295 (100 mcg) + Ipamorelin (200 mcg) combined, fasted
- 6:30 AM – Breakfast
- 5:00 PM – Resistance training session
- 6:00 PM – Post-workout: Inject IGF-1 LR3 (40–80 mcg) IM into trained muscle
- 6:30 PM – Post-workout meal (high protein)
- 10:00 PM – Last food
- 11:30 PM – Inject CJC-1295 (100 mcg) + Ipamorelin (200 mcg) combined, fasted
What to Expect
Muscle growth from this stack is gradual and cumulative, building over weeks as GH, IGF-1, and training adaptations compound. The addition of IGF-1 LR3 may accelerate anabolic signaling beyond what the GH secretagogues alone can produce.
| Timeframe | Expected Observations |
|---|---|
| Weeks 1–2 | Improved sleep depth and quality. Mild water retention and muscle fullness. Subtle increase in workout recovery speed. GH levels beginning to rise. |
| Weeks 3–4 | IGF-1 LR3 introduced (if following recommended timing). Enhanced muscle pumps during training. Beginning of measurable IGF-1 elevation on blood work. Improved recovery between sessions. |
| Weeks 5–8 | Noticeable improvements in muscle fullness and density. Increased strength and training capacity. Visible body composition changes (more muscle, less fat). Enhanced connective tissue resilience. |
| Weeks 9–12 | Peak anabolic effect period. Measurable lean mass gains. Continued fat loss from GH-mediated lipolysis. Improved skin and joint quality. IGF-1 LR3 cycle break and reassessment. |
| Weeks 13–16 | Optional second IGF-1 LR3 block. Consolidation of muscle gains. End-of-cycle assessment. Blood work for IGF-1, glucose, and overall health markers. |
Safety & Contraindications
Known Side Effects
CJC-1295 + Ipamorelin side effects: (Same as the GH Optimization Stack) Injection site reactions, mild water retention, tingling or numbness in extremities at higher doses, facial flushing. See the GH Optimization Stack for detailed safety information on these two compounds.
IGF-1 LR3 specific side effects:
- Hypoglycemia: IGF-1 LR3 can lower blood sugar, particularly when injected in a fasted state or combined with insulin. Monitor blood glucose, especially early in the cycle. Always have fast-acting carbohydrates available.
- Joint pain and swelling: IGF-1 promotes growth in joint tissue, which can cause discomfort in some individuals.
- Gut growth: High doses or prolonged use of IGF-1 LR3 may stimulate growth of intestinal smooth muscle and other organs. This is a dose-dependent concern and a primary reason for cycling.
- Injection site soreness: Intramuscular injection can cause localized pain, particularly in smaller muscle groups.
Contraindications and Cautions
- Cancer or tumor history: IGF-1 is a potent growth factor. Any history of cancer, particularly hormone-sensitive cancers, is a strict contraindication for this entire stack.
- Diabetes: IGF-1 LR3 can cause hypoglycemia. Individuals with diabetes must exercise extreme caution and monitor glucose frequently.
- Under 25 years old: Growth plate closure and natural GH/IGF-1 levels make this stack unnecessary and potentially harmful for younger individuals.
- Pregnancy and breastfeeding: Contraindicated.
- Organ enlargement concerns: Keep IGF-1 LR3 doses conservative and cycle lengths short to minimize the risk of organ growth (intestines, heart).
Important: IGF-1 LR3 is a potent growth factor with more significant risks than CJC-1295 or Ipamorelin. This stack should only be considered by experienced individuals who understand the risks and monitor their health regularly. This information is for educational purposes only and is not medical advice.
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Frequently Asked Questions
References
- Tomas FM, Knowles SE, Owens PC, et al.. Effects of full-length and truncated insulin-like growth factor-I on nitrogen balance and muscle protein metabolism in nitrogen-restricted rats. Journal of Endocrinology, 1991.
- Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Bhatt RS. 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. Journal of Clinical Endocrinology & Metabolism, 2006.
- Raun K, Hansen BS, Johansen NL, et al.. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology, 1998.
- Goldspink G. Research on mechano growth factor: its potential for optimising physical training as well as misuse in doping. British Journal of Sports Medicine, 2005.
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Our content is reviewed for accuracy and grounded in peer-reviewed research where available. We do not provide medical advice. Always consult a qualified healthcare professional.