Compare · Head-to-head
IGF-1 LR3 vs MK-677.
Evidence, risk, regulatory flags, cost, and vendor coverage compared side by side. We don’t sell peptides — we help you choose between them.
Which should you research first?
Start with MK-677, then use the table to confirm fit.
MK-677 is the cleaner first read based on the current evidence, risk, and regulatory data stored for this pair. The right answer can still change if your goal, sport testing status, vendor constraints, or monitoring tolerance makes the other option a better fit.
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01· Subject
IGF-1 LR3
Engineered IGF-1 analogue with reduced IGFBP binding and prolonged activity. Extreme growth-factor risk category.
01 · At a glance
| Decision factor | IGF-1 LR3 | MK-677 |
|---|---|---|
| Primary fit | muscle growth & strength research where you want a clear starting point | muscle growth & strength and longevity & anti-aging comparisons |
| Evidence | Tier C | Tier C |
| Risk | extreme | med-high |
| Experience level | advanced | advanced |
| Budget tier | premium | mid |
| Administration route | subcutaneous | oral |
02 · Use case & timing
| Decision factor | IGF-1 LR3 | MK-677 |
|---|---|---|
| Goal fit | Muscle Growth & Strength | Muscle Growth & Strength, Longevity & Anti-Aging, GH Axis Optimization |
| What users compare it for | Growth factor signaling; muscle growth narratives in gray market. High mitogenic/glucose risk. | Increased GH/IGF-1 signaling, appetite rise, and potential lean-mass increase in some human studies. |
| Onset timeline | Acute metabolic effects possible; anabolic narratives are speculative in consumer context. | GH rises acutely; IGF-1 and body-composition effects are tracked over weeks to months. |
| Main tradeoff | Potential upside comes with much more safety and screening caution than lower-risk alternatives. | Evidence and product availability can still be uneven, so documentation matters more than hype. |
03 · Safety & restrictions
| Decision factor | IGF-1 LR3 | MK-677 |
|---|---|---|
| Adverse effects | Hypoglycemia, mitogenic signaling, growth-factor class risks. | Edema, increased appetite, insulin resistance, elevated fasting glucose, joint discomfort, and possible cardiovascular safety concerns. |
| Contraindications | Active malignancy (by analogy to growth factor class). High interaction potential with insulin/glucose-lowering agents. | Use caution in diabetes, insulin resistance, edema-prone states, heart failure risk, and active malignancy. |
| Interaction notes | High interaction potential with insulin/glucose-lowering agents; avoid prescriptive guidance. | Combining with other GH-axis compounds increases endocrine complexity and may worsen glucose control. |
| Regulatory status | Not approved | Not approved |
| FDA flag | FDA status unclear | FDA compounding caution |
| WADA status | WADA S2 | WADA S2 |
04 · Age & monitoring
| Decision factor | IGF-1 LR3 | MK-677 |
|---|---|---|
| Supported age ranges | No age guidance yet | 25-34, 35-44, 45-54 |
| Life-stage note | Not yet documented | Most often discussed for younger and midlife adults, but metabolic and fluid-retention risks narrow the fit quickly with age. |
| Monitoring burden | Not specified | high |
| Follow-up cadence | Not yet documented | More frequent early follow-up, then reassessment every few months if continued. |
05 · Cost & sourcing
| Decision factor | IGF-1 LR3 | MK-677 |
|---|---|---|
| Typical cycle cost | $97.99 | No reliable estimate yet |
| Estimated monthly cost | $130.65 | No reliable estimate yet |
| Cost confidence | High confidence | No estimate |
06 · Before you buy
| Decision factor | IGF-1 LR3 | MK-677 |
|---|---|---|
| Tracked vendor listings | 2 listings | 0 listings |
| Sourcing note | Tracked product pages are available, which makes it easier to review the listing before you click out. | No tracked product page yet, so sourcing takes more manual review. |
| Stack-friendly? | Usually stack-friendly | Usually stack-friendly |
Sources and review notes
- Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks - U.S. Food and Drug Administration - accessed 2026-05-15
Used for FDA compounding-risk context and peptide safety flags.
- The Prohibited List - World Anti-Doping Agency - accessed 2026-05-15
Used for athlete-facing WADA risk and peptide-class restrictions.
- Peptide therapeutics: current status and future directions - PubMed / Nature Reviews Drug Discovery - accessed 2026-05-15
Used for broad peptide-therapeutics background and evidence framing.
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