Retatrutide vs IGF-1 LR3
Side-by-side comparison of key properties, dosing, and research.
GLP-1 / Weight Loss Agonists
RetatrutideAnabolic & IGF
IGF-1 LR3- Summary
- Retatrutide is an investigational triple receptor agonist targeting GLP-1, GIP, and glucagon receptors simultaneously. Phase 2 trials showed an unprecedented average 24% body weight reduction at 48 weeks — exceeding any approved medication to date. It is in Phase 3 trials as of 2024.
- IGF-1 LR3 is a synthetic analog of Insulin-like Growth Factor-1 with an extended half-life. It is one of the most potent anabolic peptides available, directly stimulating muscle cell hyperplasia and hypertrophy, and is the downstream mediator of many of GH's anabolic effects.
- Half-Life
- ~10–12 days
- 20–30 hours
- Admin Route
- SubQ
- SubQ, IM
- Research
- —
- —
- Typical Dose
- 0.5 mg → 1 mg → 2 mg → 4 mg → 8 mg → 12 mg
- 40–80 mcg
- Frequency
- Once weekly
- Once daily or split twice daily
- Key Benefits
- ~24% body weight reduction at 48 weeks in Phase 2 (highest dose)
- Superior to both semaglutide and tirzepatide in early trial comparisons
- Triple receptor mechanism addresses multiple obesity pathways
- Significant reduction in liver fat (MASH/NAFLD indication being studied)
- Improved cardiovascular and metabolic markers
- Once-weekly dosing
- Potential for greatest weight loss of any currently investigated compound
- Direct muscle hypertrophy via IGF-1R stimulation
- Muscle hyperplasia (new fiber formation) — unique among peptides
- Rapid gains in lean muscle mass
- Accelerated recovery from training and injury
- Increased nutrient uptake by muscle cells
- Fat oxidation enhancement
- Bone density improvement
- Cartilage and connective tissue repair
- Side Effects
- Nausea and vomiting (common during titration, similar to semaglutide/tirzepatide)
- Diarrhea
- Constipation
- Heart rate increase (from glucagon receptor agonism)
- +2 more
- Hypoglycemia (significant risk — insulin-like activity)
- Acromegaly-like effects with excessive long-term use
- Jaw and hand swelling
- Organ hypertrophy with extreme doses
- +2 more
- Stacks With
- —
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