IGF-1 LR3 vs MK-677.
Quick Verdict
IGF-1 LR3 is a growth factor primarily researched for muscle growth, recovery, hyperplasia, while MK-677 is a gh secretagogue (oral) studied for sustained gh/igf-1 elevation, muscle growth, improved sleep, bone density, oral dosing convenience. A key distinction: MK-677 has FDA approval status.
Side-by-Side Analysis
| Dimension | IGF-1 LR3 | MK-677 |
|---|---|---|
| Category | Growth Factor | GH Secretagogue (Oral) |
| Mechanism | IGF-1 analog with extended half-life for muscle cell hyperplasia (new cell creation, not just hypertrophy). | Non-peptide ghrelin receptor (GHSR1a) agonist that stimulates prolonged, pulsatile growth hormone release from the pituitary gland. |
| Half-Life | ~20 hours | ~1 day |
| Route | SubQ | Oral |
| Typical Dose | 50–50 mcg | 12500–12500 mcg |
| Frequency | 5x/wk | 7x/wk |
| Evidence Level | Preclinical | Moderate |
| Indexed Studies | 20+ indexed | 20+ indexed |
| FDA Status | Research Only | Approved |
| Lowest Price | $69.99 / 1mg via Amino Club | — |
Mechanism of Action Comparison
How IGF-1 LR3 Works
IGF-1 LR3 IGF-1 LR3 is a long-acting analog of Insulin-like Growth Factor 1 studied for its ability to trigger new muscle cell creation (hyperplasia) beyond what training alone can achieve.
IGF-1 analog with extended half-life for muscle cell hyperplasia (new cell creation, not just hypertrophy). Promotes nitrogen retention and protein synthesis.
How MK-677 Works
MK-677 MK-677 (Ibutamoren) is an orally bioavailable growth hormone secretagogue studied for sustainably elevating GH and IGF-1 levels over 24 hours with a single daily pill.
Non-peptide ghrelin receptor (GHSR1a) agonist that stimulates prolonged, pulsatile growth hormone release from the pituitary gland. Unlike injectable GH peptides, MK-677 is orally bioavailable with a ~24-hour half-life, enabling once-daily dosing. Increases IGF-1 levels for up to 12 months without desensitization of the GH axis. Does not suppress natural GH secretion patterns or affect cortisol levels at standard doses.
Key Mechanistic Difference
IGF-1 LR3 operates as a growth factor, while MK-677 functions as a gh secretagogue (oral) — these are fundamentally different pharmacological approaches.
Research Evidence
IGF-1 LR3
20 studies- IGF-1 LR3 promotes muscle growth in animal modelsIGF-1 LR3 demonstrates significantly enhanced potency over native IGF-1 due to reduced binding protein affinity and exte…Preclinical
- IGF-1 signaling: muscle repair and regeneration reviewPhilippou & Barton (Growth Hormone & IGF Res.): Comprehensive review of IGF-1's role in muscle satellite cell activation…Preclinical
- IGF-1 and cancer risk comprehensive epidemiological reviewBowers et al.: Meta-analysis of epidemiological studies examining positive correlation between circulating IGF-1 levels …Moderate-Strong
MK-677
20 studies- MK-677 increases GH and IGF-1 without altering cortisol in healthy elderlyChapman et al. (J. Clin. Endocrinol. Metab.): 25mg daily MK-677 for 2 weeks in healthy elderly subjects restored IGF-1 a…Moderate
- MK-677 2-year study: sustained IGF-1 elevation and body composition effectsNass et al. (J. Clin. Endocrinol. Metab.): 2-year RCT in 65 healthy elderly adults. 25mg/day MK-677 increased GH and IGF…Strong
- MK-677 increases fat-free mass in healthy obese malesSvensson et al. (J. Clin. Endocrinol. Metab.): 8-week RCT in obese males. 25mg/day MK-677 significantly increased GH sec…Moderate
Vendor Pricing
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Frequently Asked Questions
Can I take IGF-1 LR3 and MK-677 together?▼
No direct interaction data is available for this specific pair. They target different receptor systems, suggesting they could potentially be combined, but no published protocol validates this combination.
Which has more research evidence — IGF-1 LR3 or MK-677?▼
IGF-1 LR3 has 20 indexed studies (highest evidence: Preclinical). MK-677 has 20 indexed studies (highest evidence: Moderate). Both have comparable research coverage.
Which is better for muscle growth — IGF-1 LR3 or MK-677?▼
Both are researched for muscle growth. IGF-1 LR3 addresses this via muscle growth, recovery, hyperplasia. MK-677 approaches it through sustained gh/igf-1 elevation, muscle growth, improved sleep, bone density, oral dosing convenience. The optimal choice depends on your specific research protocol and which mechanism aligns with your objectives.
Is IGF-1 LR3 or MK-677 FDA-approved?▼
MK-677 has FDA approval (or is derived from an FDA-approved compound). IGF-1 LR3 is a research compound without FDA approval for human use. FDA status reflects regulatory evaluation — not necessarily superiority for all research applications.
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Research Use Only — Not Medical Advice
This comparison is provided for educational and research purposes only. It does not constitute medical, prescribing, or treatment advice. Clinical data cited here is sourced from published peer-reviewed trials and FDA labels. Consult a qualified healthcare professional before making any decisions about medications or research compounds. PeptiDex is an informational resource and does not sell pharmaceutical products.