Hexarelin vs IGF-1 LR3
A neutral, side-by-side comparison of two performance & growth hormone peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Hexarelin
Hexarelin is a potent synthetic hexapeptide GHRP (Growth Hormone-Releasing Peptide) that stimulates GH release via the ghrelin receptor. It produces among the highest GH pulses of any GHRP, but also elevates cortisol and prolactin — a trade-off that distinguishes it from more selective options like Ipamorelin.
Full profileIGF-1 LR3
IGF-1 LR3 (Long Arg3 IGF-1) is a synthetic analogue of Insulin-like Growth Factor 1 with an amino acid substitution at position 3 and a 13-amino acid N-terminal extension. These modifications prevent binding to IGF-binding proteins (IGFBPs), dramatically extending its half-life from ~12 minutes (native IGF-1) to approximately 20–30 hours. IGF-1 LR3 is widely used in research for its ability to promote cellular growth, protein synthesis, hyperplasia, and nutrient uptake into muscle tissue.
Full profile| Hexarelin | IGF-1 LR3 | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | Examorelin, EP 23905, MF-6003 | Insulin-like Growth Factor-1 Long R3, Long R3 IGF-1, Increlex (human equivalent) |
| Evidence | Preclinical only | Research-stage |
| Dosing range | 50mcg–200mcg mcg, 1–3x daily (cycling recommended to prevent desensitization) | 20mcg–100mcg mcg, Once daily post-workout, on training days only (common protocol) |
| Administration | Subcutaneous injection, Intramuscular injection | Subcutaneous injection, Intramuscular injection (into the trained muscle — site-specific protocols) |
| Key side effects | Cortisol elevation, Prolactin elevation, Water retention, Increased appetite | Hypoglycemia (clinically significant — monitor blood sugar carefully), Jaw and organ growth with chronic high-dose use (theoretical at research doses), Fatigue and headaches, Joint pain |
| Cited sources | 1 reference | 3 references |
Key differences
- Evidence level differs: Hexarelin is preclinical only, while IGF-1 LR3 is research-stage.
- Administration: Hexarelin — Subcutaneous injection, Intramuscular injection; IGF-1 LR3 — Subcutaneous injection, Intramuscular injection (into the trained muscle — site-specific protocols).
- Frequency: Hexarelin is typically 1–3x daily (cycling recommended to prevent desensitization); IGF-1 LR3 is Once daily post-workout, on training days only (common protocol).
- Research depth: this profile cites 1 source for Hexarelin vs 3 for IGF-1 LR3.
How each works
Hexarelin
Hexarelin produces dose-dependent GH release significantly greater than GHRP-6 or Ipamorelin. It also has direct cardioprotective effects via CD36 receptor binding, independent of GH — making it unique among GHRPs. Studies show protection from ischemic cardiac injury and myocardial fibrosis reduction in animal models. Desensitization occurs with chronic continuous use.
IGF-1 LR3
In vitro and animal research establishes IGF-1 LR3 as a potent anabolic and growth-promoting agent. It activates the IGF-1 receptor (IGF-1R) and downstream PI3K/Akt and MAPK/Erk pathways, promoting skeletal muscle hypertrophy and satellite cell activation. Its extended half-life makes it far more active systemically than native IGF-1. Research also documents its role in connective tissue repair, nerve regeneration, and fat oxidation. Human research is limited — most data comes from cancer cell biology and athletic performance settings.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.