01 / IDENTITY
Compound Profile
CLASSIFICATION
Recombinant IGF-1 analog. LR3 = "Long Arg3" — glutamic acid at position 3 replaced with arginine (reduces IGFBP binding 1000×); 13-amino-acid N-terminal extension (increases half-life from 15 min → 20–30 hours).
MECHANISM
Binds IGF-1 receptor (IGF-1R) with high affinity → activates PI3K/Akt/mTOR (anabolic growth) and Ras/ERK (proliferation) pathways. Downstream of GH axis: liver produces IGF-1 in response to GH; IGF-1 LR3 mimics this but at higher circulating concentration and longer duration due to reduced IGFBP binding.
VIAL SIZE
1 mg (1,000 mcg) — precision dosing required. This is a HIGH-POTENCY compound. Very small volumes per dose.
vs. NATIVE IGF-1
Native IGF-1: 15-minute half-life (bound by IGFBPs). IGF-1 LR3: 20–30 hour half-life (resists IGFBP binding). Result: dramatically more bioavailability and sustained receptor activation from the same dose.
DEVELOPER
Originally developed by Gropep Ltd (Australia); licensed for research use. Never FDA-approved for clinical use (unlike mecasermin/Increlex which is native IGF-1).
02 / RESEARCH HISTORY
Development Timeline
1957–1970s
William Daughaday (Washington University) characterizes "sulfation factor" as the mediator of growth hormone's anabolic effects — later renamed Somatomedin-C, then IGF-1. The GH → liver → IGF-1 → tissue growth axis established as the primary anabolic endocrine pathway.
1987
Recombinant IGF-1 synthesis achieved. Therapeutic trials begin for growth hormone insensitivity syndrome (Laron syndrome) — children who cannot respond to GH but can respond to direct IGF-1 treatment. FDA approval of mecasermin (Increlex) follows in 2005 for Laron syndrome.
1992
Gropep (Australia) develops IGF-1 LR3 — a modified analog with 13-amino-acid extension and Arg3 substitution. Half-life extends from 15 minutes to 20–30+ hours. 1000× reduction in IGFBP-3 binding affinity. Purpose: research tool to study IGF-1 signaling with sustained receptor activation. Becomes available for cell culture and in vivo research.
2000–2010
IGF-1 LR3 enters bodybuilding/performance community. Significant underground research accumulated on muscle satellite cell activation, localized (intramuscular) effects, and systemic dosing protocols. Recognized as distinct from GH — works directly at muscle tissue without hepatic conversion step.
2010–2024
Continued research into IGF-1's role in muscle satellite cell biology, tendon repair, and neurological regeneration. IGF-1 LR3 used as research tool in studies of muscle wasting, ALS, and spinal cord injury models. Performance applications well-characterized in community research despite lack of clinical trials.
03 / BENEFITS
Primary Effects
01
Muscle Satellite Cell Activation
The most unique and powerful effect of IGF-1 LR3 vs. other anabolic agents: direct activation of skeletal muscle satellite cells — the stem cells that repair and grow muscle fibers. IGF-1 signaling through IGF-1R → PI3K/Akt → MyoD/myogenin transcription factors → satellite cell proliferation and differentiation into new myofibers. This is actual new muscle cell generation, not just hypertrophy of existing cells.
02
mTOR Activation — Protein Synthesis
IGF-1R → Akt → mTORC1 is the most potent anabolic signaling cascade in skeletal muscle. IGF-1 LR3 sustains this activation for 20–30 hours per dose (vs. 15 minutes with native IGF-1), creating a prolonged anabolic window. Dramatically increases protein synthesis rate and nitrogen retention.
03
Anti-Catabolic Protection
IGF-1/Akt signaling phosphorylates and inhibits FoxO transcription factors — the primary drivers of muscle protein catabolism (atrophy genes). IGF-1 LR3 provides 24-hour protection against muscle breakdown, particularly valuable during caloric deficit or high-volume training phases.
04
Tissue Repair — Tendons, Ligaments, Cartilage
IGF-1 receptors are present in tendons, ligaments, and cartilage. IGF-1 LR3 stimulates collagen synthesis and fibroblast proliferation in these tissues. Often stacked with BPC-157 and TB-500 for enhanced tendon/ligament repair — complementary but distinct mechanisms.
05
Neuroregeneration & Neuroprotection
Brain and peripheral nervous system express high levels of IGF-1R. IGF-1 promotes neuronal survival, axonal sprouting, and myelination. IGF-1 LR3 crosses the blood-brain barrier at lower efficiency than native IGF-1 but still exerts neurological effects — improved cognitive function and faster nerve injury recovery reported.
06
Fat Loss — Lipolytic and Anti-Lipogenic
IGF-1 signaling in adipose tissue promotes lipolysis and inhibits de novo lipogenesis. Paradoxically, despite being a "growth" factor, optimized IGF-1 levels are associated with lower body fat — consistent with the observation that GH-deficient adults are fat and IGF-1-replete athletes are lean.
04 / RECONSTITUTION
Preparation Protocol — PRECISION CRITICAL
⚠ PRECISION DOSING — 1mg VIAL — READ CAREFULLY
// 1MG VIAL — PRECISION RECONSTITUTION
1,000 mcg ÷ 300 units BAC water = 3.33 mcg per unit
Add 3.0 mL (300 units) bacteriostatic water to 1mg lyophilized vial.
CRITICAL — Very Small Volumes: At 3.33 mcg/unit, a 50mcg dose = 15 units = 0.15 mL. A 100mcg dose = 30 units = 0.30 mL. Use a 1mL insulin syringe for accuracy. The total vial contains only 1mg — miscalculation wastes expensive product or causes overdose. Triple-check your math before drawing.
| TARGET DOSE |
UNITS TO DRAW |
VOLUME |
NOTE |
| LOW20 mcg |
6 units |
0.06 mL |
Women / first use / conservative |
| STANDARD50 mcg |
15 units |
0.15 mL |
Standard male protocol |
| HIGH100 mcg |
30 units |
0.30 mL |
Experienced users; upper range |
| MAX150 mcg |
45 units |
0.45 mL |
Not recommended; hypoglycemia risk |
Alternative Reconstitution for Higher Concentrations: To make doses easier to measure, reconstitute with 1.0 mL BAC water instead of 3.0 mL → concentration = 1 mcg/unit (1,000 mcg/mL). Then: 50mcg = 50 units = 0.50 mL. Easier to measure but uses more BAC water per draw; shelf life may be slightly shorter.
Storage: Lyophilized — refrigerate (4°C), protect from light. Reconstituted: refrigerate (4°C), use within 30 days. IGF-1 LR3 is somewhat less stable than many peptides once reconstituted — do not leave at room temperature for extended periods.
05 / DOSING PROTOCOL
Administration Guide
| PROTOCOL |
DOSE |
FREQUENCY |
DURATION |
CONTEXT |
| INTRO |
20–30 mcg SC |
Daily |
1 week |
Assess hypoglycemia sensitivity |
| STANDARD |
50–80 mcg SC/IM |
Daily (post-workout) |
4–8 weeks |
Muscle growth, satellite cell activation |
| ADVANCED |
80–100 mcg SC/IM |
Daily |
4–6 weeks |
Maximum anabolic phase; monitor BG |
| REPAIR |
40–60 mcg SC (local) |
Daily |
4–8 weeks |
Localized tissue repair with BPC-157/TB-500 |
Hypoglycemia Risk: IGF-1 LR3 has significant insulin-mimetic activity at the cellular level. Risk of symptomatic hypoglycemia — especially if injected without eating. ALWAYS have fast-acting carbohydrates on hand. Inject post-workout with a carbohydrate/protein meal, never fasted. Symptoms: sweating, dizziness, confusion, shakiness. Treat immediately with glucose.
IM vs. SC: Intramuscular injection (into target muscle, post-workout) delivers IGF-1 LR3 directly to recently-trained tissue where IGF-1R upregulation is highest. Produces localized hypertrophy effect. Subcutaneous is more convenient and still effective for systemic anabolic/recovery effects.
06 / TIMING
Administration Timing
CRITICAL — POST-WORKOUT ONLY
Inject immediately post-workout (within 30 minutes) while IGF-1R expression is elevated from training stimulus. This is when satellite cells are most receptive. DO NOT inject fasted.
FOOD TIMING
Always pair with carbohydrates + protein immediately after injection. 30–50g fast carbs + 30–40g protein. This manages hypoglycemia risk while providing substrates for the mTOR-driven protein synthesis that IGF-1 initiates.
HALF-LIFE NOTE
20–30 hour half-life means once-daily dosing maintains elevated IGF-1 receptor activity throughout the day. Some users prefer twice-daily (split dose: post-workout + morning) — reduces hypoglycemia risk per injection vs. single higher dose.
STACKING
Synergistic with GH peptides (Ipamorelin/CJC — they stimulate endogenous GH → liver IGF-1 production; exogenous IGF-1 LR3 amplifies the downstream effect). BPC-157 + IGF-1 LR3 = powerful tissue repair combination.
07 / BIOMARKERS
Monitoring Panel
// IGF-1 AXIS
| MARKER | TEST | CLINICAL RANGE | TARGET ON IGF-1 LR3 |
|---|
| IGF-1 (Total)Serum IGF-1 |
Morning serum draw |
CLINAge-dependent (20s: 115–307 ng/mL) |
NOTEIGF-1 LR3 does NOT elevate standard IGF-1 assay reliably (IGFBP changes confound results) |
| IGFBP-3IGF Binding Protein 3 |
Serum |
CLIN1.6–6.1 mg/L (adult) |
NOTEMay decrease on IGF-1 LR3 (competitive displacement) |
| Fasting InsulinInsulin Resistance |
Fasting AM draw |
CLIN2–25 µIU/mL |
OPT<6 µIU/mL — monitor for suppression (IGF-1 may lower insulin requirements) |
// SAFETY — GLUCOSE & ONCOLOGY MARKERS
| MARKER | TEST | CLINICAL RANGE | MONITOR FOR |
|---|
| Fasting Blood GlucoseFBG |
Daily home glucometer |
CLIN70–99 mg/dL |
FLAG<70 mg/dL = hypoglycemia event → treat & reduce dose |
| PSA (males)Prostate-Specific Antigen |
Standard cancer marker |
CLIN<4.0 ng/mL (age <50) |
FLAGIGF-1 is a growth factor — monitor PSA in males 45+. Any rise → discontinue & evaluate |
| CEACarcinoembryonic Antigen |
Standard tumor marker |
CLIN<2.5 ng/mL (non-smoker) |
FLAGGrowth factor potential — baseline + annual monitoring recommended for extended use |
// PERFORMANCE TRACKING
| MARKER | TEST | BASELINE | EXPECTED CHANGE |
|---|
| DEXA Body CompositionLean Mass / Fat Mass |
DEXA scan (pre + post cycle) |
BASEPre-cycle scan |
EXP+1–3 lbs lean mass / 4–8 week cycle typical |
| Strength Testing1RM Compound Lifts |
Gym tracking |
BASEPre-cycle 1RM |
EXP5–15% strength increase over 6–8 weeks |
08 / CYCLE PROTOCOL
Recommended Cycle
Weeks 1 (Intro): 20–30 mcg SC daily post-workout. Assess for hypoglycemia — note blood glucose 30 min, 60 min, and 90 min post-injection. If stable, proceed to full protocol.
Weeks 2–8 (Active Phase): 50–100 mcg SC or IM post-workout daily. Always with carbs + protein post-injection. Training intensity should be high — IGF-1 LR3 requires mechanical stimulus to drive satellite cell activation. Higher training volume = better results.
Off Period: Minimum 4 weeks off (equal to cycle length). IGF-1 LR3 downregulates its own receptor with chronic exposure — cycling maintains receptor sensitivity. During off-cycle, continue GH peptides (Ipamorelin/CJC) to maintain endogenous IGF-1 production.
Stack Protocol: Ipamorelin 200mcg + CJC-1295 200mcg (bedtime, fasted) PLUS IGF-1 LR3 50–80mcg (post-workout) = complete GH axis stimulation at both the pituitary level (Ipa/CJC) and the tissue level (LR3). Add BPC-157 for connective tissue protection during high-intensity training.
Important Research Compound Notice: IGF-1 LR3 is a high-potency anabolic growth factor. It has NOT been approved for human use by the FDA. It carries a real hypoglycemia risk — always dose post-workout with food. Due to IGF-1's role in cellular growth, there is a theoretical cancer promotion risk with supraphysiological levels — this compound is contraindicated if you have a personal history of cancer or are at high risk. Mandatory cancer marker monitoring for any extended use protocol. Consult a qualified healthcare provider before use.