01 / IDENTITY

Compound Profile

83

AMINO ACIDS

~9.1

kDa MW

SC/IM

ROUTE

20–30h

HALF-LIFE

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

10 mg (10,000 mcg) — reconstitute with 1 mL BAC water for a working concentration of 100 mcg per unit. Precision dosing required.

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.

RECONSTITUTION: Add 1.0 mL bacteriostatic water to a 10 mg lyophilized vial → concentration = 100 mcg per unit (0.01 mL). At this concentration: 200 mcg = 2 units | 500 mcg = 5 units | 1,000 mcg = 10 units. Use a 1 mL insulin syringe. Precision matters — triple-check your draw before injecting.

TARGET DOSE	UNITS TO DRAW	VOLUME	NOTE
LOW200 mcg	2 units	0.02 mL	Starting dose / first use / sensitivity assessment
STANDARD500 mcg	5 units	0.05 mL	Standard protocol — muscle growth, satellite cell activation
AGGRESSIVE1,000 mcg (1mg)	10 units	0.10 mL	Advanced / maximum anabolic phase; monitor blood glucose closely

Standard Protocol: Reconstitute 10 mg vial with 1.0 mL BAC water → 100 mcg/unit. This gives clean, easy-to-read volumes. Keep refrigerated after reconstitution; use within 30 days. The Apex V3 pen delivers these small draw volumes with precision — no guessing, no waste.

🧊

RECONSTITUTED SHELF LIFE

30 days after mixing

Long-acting IGF-1 analog. 30-day window standard.

            Storage: 2–8°C (fridge) · Protected from light · Do NOT freeze

            Preload syringes/cartridges to minimize vial disturbance

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	200 mcg SC	Daily	1 week	Assess hypoglycemia sensitivity, establish baseline tolerance
STANDARD	500 mcg SC/IM	Daily (post-workout)	4–8 weeks	Muscle growth, satellite cell activation, recovery enhancement
AGGRESSIVE	1,000 mcg (1mg) SC/IM	Daily	4–6 weeks	Maximum anabolic phase; monitor blood glucose closely
REPAIR	200–500 mcg SC (local)	Daily	4–8 weeks	Localized tissue repair stacked 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

4–8

WEEKS ACTIVE

7

DAYS PER WEEK

4–8

WEEKS OFF

Post-WO

INJECTION TIME

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.

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Drop IGF-1 LR3 into your protocol tracker — dosing pre-filled, timing set, cycle ready.

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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.