IGF-1 LR3 (Long R3 IGF-1)

Modified Growth Factor Analog | Muscle Growth

Half-life: 20-30 hours
Chain: 83 amino acids
4 studies
2023 latest
2 recent
limited
Dose 20-100 mcg daily (start low at 20-30 mcg)
Frequency Once daily, or split AM/PM for higher doses
Cycle 4-6 weeks maximum
Storage Lyophilized: -20°C to -80°C. Reconstituted in acetic acid: 2-8°C for 1 year. Reconstituted in BAC water: use within 7 days
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IGF-1 LR3 is a synthetic 83-amino acid analog of insulin-like growth factor-1 that has never been approved for human use. The N-terminal extension and R3 substitution reduce binding protein interaction, maintaining elevated free circulating levels with ~3x greater potency than native IGF-1.

Mechanism of Action

Functions as a full IGF-1 receptor agonist activating PI3K/Akt/mTOR and MAPK/ERK pathways. The modifications prevent protein sequestration, maintaining elevated free circulating levels for extended anabolic effects.

01 Approximately 3x more potent than native IGF-1
02 Promotes muscle hypertrophy and hyperplasia in animal models
03 15-20% lean mass gains observed in 4-week rat studies
04 Anti-catabolic effects preserve muscle during cachexia
05 20-30 hour half-life for sustained effects

Molecular Data

Chain Length
83 amino acids
Type
Synthetic IGF-1 analog
Peak 0.0 mcg
Trough 0.0 mcg
SS Peak 0.0 mcg
SS Trough 0.0 mcg

Research Indications

Muscle Growth
Hypertrophy most effective

15-20% lean mass gains in 4 weeks through satellite cell activation (rat studies).

Anti-Catabolic effective

Cancer cachexia rats maintained 30% more muscle versus placebo.

Hyperplasia effective

Creates new muscle fibers via satellite cell differentiation.

Tissue Repair
Wound Healing effective

Accelerated wound healing in animal models.

Ligament/Tendon Recovery moderate

Enhanced connective tissue repair.

Metabolic
Nutrient Partitioning moderate

Directs nutrients toward muscle tissue.

Fat Loss moderate

Enhanced lipolysis through IGF-1 pathway.

Dosing Protocols

Subcutaneous or intramuscular injection. CRITICAL: Consume 30-60g fast carbohydrates immediately after injection to prevent hypoglycemia. Never inject before sleep.

GoalDoseFrequencyRoute
Beginner Protocol20-30mcgOnce daily post-workoutSubQ/IM
Intermediate40-60mcgOnce dailySubQ/IM
Advanced80-100mcgOnce or split AM/PMSubQ/IM
Women's Protocol10-20mcgOnce dailySubQ/IM

Reconstitution Instructions

Materials Needed:
  • IGF-1 LR3 lyophilized powder
  • 0.6% acetic acid OR bacteriostatic water
  • Insulin syringes (29-32 gauge)
  • Alcohol swabs
  1. 1 Equilibrate to room temperature (15-30 min)
  2. 2 Sanitize rubber stopper with alcohol
  3. 3 Calculate concentration (e.g., 1mg in 2mL = 500mcg/mL)
  4. 4 Inject diluent slowly along vial wall
  5. 5 Gently swirl - never shake vigorously
  6. 6 Allow 2-5 minutes for complete dissolution
  7. 7 Store immediately at 2-8°C protected from light
  8. 8 Acetic acid reconstitution: stable 1 year
  9. 9 BAC water reconstitution: use within 7 days

Interactions

!
Human Growth Hormone
Creates excessive IGF-1 levels; avoid combination.
avoid
~
CJC-1295/Ipamorelin
Both stimulate GH/IGF-1 axis; use caution with combination.
monitor
~
MK-677
May compound metabolic effects through GH stimulation.
monitor
!
Insulin
Synergistic hypoglycemic effects can be life-threatening.
avoid
++
BPC-157
Complementary healing mechanisms.
synergistic
++
TB-500
Different repair pathway activation.
synergistic
~
Anabolic Steroids
Amplified effects with increased risks.
monitor
~
Metformin
May mitigate insulin resistance.
monitor
~
Cerebrolysin
Additive neurotrophic pathway effects.
monitor

What to Expect

Week 1-2
Increased muscle pump and fullness; possible hypoglycemia if carbs inadequate
Week 2-4
Enhanced recovery, strength gains, visible fullness, potential water retention
Week 4-6
Maximum effects; receptor desensitization approaching; joint stiffness common
Post-cycle
Pump loss over 1-2 weeks; strength/size gains may persist with training

Side Effects & Safety

Common Side Effects

  • Hypoglycemia (lasting up to 30 hours) - CRITICAL
  • Water retention
  • Joint stiffness
  • Muscle soreness
  • Increased pump during workouts

Stop Signs - Discontinue if:

  • Severe or recurring hypoglycemia despite carbohydrate intake
  • Unusual growths, lumps, or rapid mole changes
  • Severe joint pain or carpal tunnel symptoms
  • Persistent nausea, headaches, or vision changes
  • Signs of organ enlargement
  • Extreme fatigue or mental fog

Contraindications

  • NEVER approved for human use - research chemical only
  • Cancer history or undiagnosed growths
  • May cause organ hypertrophy (heart, intestines)
  • WADA prohibited - causes failed drug tests

Quality Checklist

Good Signs

  • HPLC purity >95%
  • Mass spectrometry confirmation
  • Cold storage maintained (-20°C lyophilized)
  • Certificate of analysis from reputable source

Warning Signs

  • Research chemical status - never approved for human use
  • Zero human clinical trials exist
  • Species-specific responses vary significantly

Bad Signs

  • Severe hypoglycemia risk - life-threatening low blood sugar lasting 20-30 hours
  • Cancer proliferation concern - UK Biobank links elevated IGF-1 to multiple cancers
  • Black market quality varies - oxidized and degraded forms common

References

  • Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats
    Tomas FM, Knowles SE, Owens PC, Chandler CS, Francis GL, Read LC, Ballard FJ
    Biochemical Journal (1992)

    LR3IGF-I was approximately 2.5-fold more potent than native IGF-1 in reversing dexamethasone-induced catabolism. 7-day treatment showed significant body weight recovery vs 19g loss in controls.

  • Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets
    Stremming J, White A, Galan HL, Brown LD
    American Journal of Physiology - Regulatory, Integrative and Comparative Physiology (2023)

    Fetal plasma insulin concentrations decreased 66% with IGF-1 LR3 infusion during hyperglycemic clamp. Insulin secretion suppression was acute and did not persist in isolated islets.

  • Insulin-like growth factor I preserves host lean tissue mass in cancer cachexia
    Ng EH, Rock CS, Lazarus DD, Stiaino-Coico L, Moldawer LL, Bhatt GR
    American Journal of Physiology (1992)

    IGF-1 treatment effectively attenuated host muscle protein and lean tissue depletion in a sarcoma model without stimulating tumor growth. Dose-dependent increases in carcass weight and gastrocnemius muscle protein.

  • Circulating Insulin-like Growth Factor-I Concentrations and Risk of 30 Cancers: Prospective Analyses in UK Biobank
    Murphy N, Knuppel A, Papadimitriou N, Martin RM, Tsilidis KK, Brennan P et al.
    Cancer Research (2020)

    Higher circulating IGF-1 associated with increased risks of colorectal, breast, prostate, and thyroid cancers in the UK Biobank prospective cohort of >395,000 participants.

Related Peptides

BPC-157 synergistic

Complementary healing mechanisms.

TB-500 synergistic

Different repair pathway activation.

Disclaimer

This information is for educational and research purposes only. Consult a healthcare professional before use.