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IGF-1 LR3

FDA: research-only
Last updated · 2026-04-12

IGF-1 LR3 is a long-acting analog of insulin-like growth factor 1 with direct action on muscle tissue. It increases contractile tissue, enhances recovery, and supports growth of high-frequency-use muscles. Its extended half-life makes it more potent than native IGF-1. Direct action on muscle tissue via IGF-1 receptor binding. Increases contractile tissue and satellite cell proliferation. Enhances recovery and growth of high-frequency-use muscles. Supports muscle retention during caloric deficit. Longer half-life than native IGF-1 or IGF-1 DES for more systemic effects. - Muscle hypertrophy and localized muscle growth - Recovery enhancement - Sprint power and strength gains - Lean mass preservation

This content is for educational and research purposes only. VialBase does not provide medical advice. Consult a healthcare professional before using any peptide.

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Where to buy IGF-1 LR3 →Swiss Chems · save 10% code aewpzbzd
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Research summary

Study Type Year Key Finding
Detection of His-tagged Long-R³-IGF-I in a black market product. Analytical case report (forensic identification of a black market injection vial's contents) 2010 An injection vial obtained from the black market was found to contain His-tagged Long-R³-IGF-I — a form usually produced for biochemical studies, not for human injection
Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting. Preclinical study (in vitro C2C12 myotubes and in vivo C26-CD2F1 mouse cachexia model) — no human data 2019 LONG R3 (LR3) IGF-I treatment limited loss of muscle mass in the C26 tumour-bearing mouse cachexia model, but at the expense of accelerated tumour growth
Sheep recombinant IGF-1 promotes organ-specific growth in fetal sheep. Animal study (fetal sheep in vivo infusion plus in vitro myoblast work) — no human data 2022 LR3 IGF-1 has a low affinity for IGF binding proteins (IGFBP), which reduces physiologic regulation of IGF-1 bioavailability — the authors treat this as a limitation of the analogue, not an advantage
Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets. Animal study (fetal sheep in vivo infusion with hyperglycemic clamp plus isolated islet experiments) — no human data 2023 Fetal plasma insulin concentrations decreased during IGF-1 LR3 infusion (P < 0.05) — a direct metabolic effect of the analogue
Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig. Animal study (guinea pig; 7-day continuous IGF infusion) — no human data 1995 Female guinea pigs (350 g body weight) were continuously infused for 7 days with recombinant guinea pig IGF-I or IGF-II (120 or 360 micrograms/day) or Long R3 IGF-I (120 micrograms/day), an analogue with much reduced affinities for IGF binding proteins

Stacks containing IGF-1 LR3

Anabolic Growth

CJC-1295 (w/ DAC) + Ipamorelin + IGF-1 LR3

Spartan

CJC-1295 + Ipamorelin + IGF-1 LR3 + BPC-157

T-Boost & GH Sync

Kisspeptin-10 + CJC-1295 + Ipamorelin + IGF-1 LR3 (low dose)

28-day resets featuring IGF-1 LR3

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What bloodwork do I need?

Reference ranges are general guidelines. Consult your physician for interpretation.

PRE-CYCLE
  • IGF-1
  • Fasting Glucose
  • Fasting Insulin
  • CMP
  • CBC
DURING CYCLE
  • IGF-1
  • Fasting Glucose
  • Fasting Insulin
POST-CYCLE
  • IGF-1
  • Fasting Glucose
  • Fasting Insulin
Safety & Regulatory Status
FDA STATUS research-only

Regulatory status for IGF-1 LR3 may change. Verify current status with your jurisdiction before use. This is not legal or medical advice.

Frequently Asked Questions

What is IGF-1 LR3?
IGF-1 LR3 is a long-acting analog of insulin-like growth factor 1 with direct action on muscle tissue. It increases contractile tissue, enhances recovery, and supports growth of high-frequency-use muscles.
How does IGF-1 LR3 work?
Direct action on muscle tissue via IGF-1 receptor binding. Increases contractile tissue and satellite cell proliferation. Enhances recovery and growth of high-frequency-use muscles.
How is IGF-1 LR3 dosed?
Standard: 10-20 mcg post-workout 2-3x/week; Muscle-specific: 20-40 mcg into target muscles (biceps/forearms); Higher dose: 30-50 mcg SubQ post-workout; Cycle: 4-6 week blocks; Route: IM (local injection into target muscle), SubQ. These figures reflect commonly cited research protocols, not medical advice — consult a clinician.
Is IGF-1 LR3 FDA-approved?
IGF-1 LR3 is a research-only compound and is not FDA-approved. Research-only — not FDA-approved for human use; Banned in competitive sports; Available through research chemical suppliers.

References

  1. Kohler M, Thomas A, Walpurgis K, et al.. Detection of His-tagged Long-R³-IGF-I in a black market product.. Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society (2010). PMID: 20675162
  2. Levolger S, Wiemer EAC, van Vugt JLA, et al.. Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting.. Scientific reports (2019). PMID: 31285507
  3. Stremming J, White A, Donthi A, et al.. Sheep recombinant IGF-1 promotes organ-specific growth in fetal sheep.. Frontiers in physiology (2022). PMID: 36091374
  4. White A, Stremming J, Brown LD, et al.. Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets.. Journal of developmental origins of health and disease (2023). PMID: 37114757
  5. Conlon MA, Tomas FM, Owens PC, et al.. Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig.. The Journal of endocrinology (1995). PMID: 7561636