NOT MEDICAL ADVICE

IGF-1 LR3

Estimated Market Price
$139.99 $154.99
Based on verified supplier pricing for research-grade compounds
Extended half-life insulin-like growth factor for maximum anabolic activity. Drives protein synthesis, nutrient partitioning, and muscle cell hyperplasia.
How it works

A modified version of IGF-1 that stays active much longer because it dodges the binding proteins that normally deactivate it. Drives muscle growth, protein synthesis, and satellite cell activation more potently than native IGF-1.

Growth Hormone

Performance

What to Expect
Days 1–3 IGF-1R activation begins; enhanced nutrient partitioning. Muscles feel fuller; better pumps in the gym.
Week 1–2 Satellite cell proliferation increasing; pumps and fullness. Strength going up; muscles recovering faster between sets.
Week 3–4 Muscle hypertrophy accelerating; measurable strength gains. Visible muscle growth; strength gains accelerating.
Week 5–6 Peak anabolic effect; cycle completing for off-period. Peak size and strength gains; muscles feel dense.

Verified Suppliers

For research purposes only. These suppliers have been independently verified by PepSpace. We do not process sales directly.

PepSpace is not affiliated with any listed supplier
Protocol & Dosage
Typical Dosage 20–50 mcg SC or IM daily
Administration Subcutaneous injection, Intramuscular injection
Schedule Once daily, post-workout or AM
Protocol Duration 4–6 weeks
Half-Life ~20-30 hours (vs ~15 min for native IGF-1)
Side Effects & Safety
Tolerability Profile Elevated

Significant side effects; medical monitoring recommended

Common Side Effects

  • Hypoglycemia (blood sugar drop)most users
  • Joint painsome users
  • Water retentionsome users

Less Common

  • Headacheoccasional
  • Nauseaoccasional
  • Muscle crampsoccasional
  • Jaw or hand growth (prolonged abuse)occasional

Rare / Serious

  • Accelerated tumor growth (IGF-1 is a growth factor)theoretical
  • Cardiomegaly (chronic high-dose abuse)rare
  • Organ enlargementrare

Discontinue If

  • Severe hypoglycemia (shaking, confusion, loss of consciousness)
  • Any signs of tumor growth or new masses
  • Persistent joint pain or swelling
  • Cardiac symptoms (chest pain, shortness of breath)

Contraindications

  • Active cancer or tumors (growth factor)
  • Diabetes mellitus
  • Pregnancy or breastfeeding
  • Acromegaly or pituitary disorders

Data note: Extended-acting IGF-1 analog with 3x longer half-life than native IGF-1. Potent growth factor — hypoglycemia risk is real and dose-dependent. Not for unsupervised use.

Always consult a qualified healthcare professional before use. This information is for research reference only and does not constitute medical advice.

Ask about IGF-1 LR3
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How to Apply

1

Gather

Peptide vial, BAC water, alcohol swabs, insulin syringe

2

Sanitize

Wipe tops of both vials with alcohol swabs

3

Draw

Pull 1–2 mL of BAC water into syringe

4

Add Water

Release water slowly along vial wall, not directly on powder

5

Swirl

Roll between palms until dissolved. Never shake.

6

Store

Refrigerate 2–8°C, use within 30 days

Frequently Asked Questions

Yes. Bacteriostatic water (BAC water) is required to reconstitute lyophilized (freeze-dried) peptides. It contains 0.9% benzyl alcohol which prevents bacterial growth, keeping your reconstituted peptide safe for multiple uses over up to 30 days.

Unreconstituted: store at -20°C (freezer) for long-term, or 2–8°C (fridge) for short-term. After reconstitution: always refrigerate at 2–8°C and use within 30 days. Keep away from direct sunlight.

Results vary by individual and protocol. In research settings, measurable effects are typically observed within 1–4 weeks depending on the specific peptide, dosage, and application. Consult a qualified professional for guidance.

Verified suppliers typically include a full third-party COA verifying purity (99%+), identity, and sterility. We recommend only sourcing from vendors that provide batch-specific testing data.

We list verified suppliers above that have been independently reviewed for product quality, testing transparency, and shipping reliability. Always verify COA data before sourcing.

Compound Profile

Scientific data & classification for IGF-1 LR3

Also Known As Long R3 IGF-1, LR3-IGF-1, IGF-1 Long R3
Classification Modified Growth Factor · Anabolic
Sequence 83 amino acid modified IGF-1 (13 aa N-terminal extension + Arg3 substitution)
Molecular Formula Recombinant protein (~9.1 kDa)
Molecular Weight ~9,111 Da
CAS Number 946870-92-4
Half-Life ~20-30 hours (vs ~15 min for native IGF-1)
Origin Recombinant modified insulin-like growth factor 1
Administration Subcutaneous injection, Intramuscular injection
Status Research compound
Mechanism of Action A modified version of IGF-1 that stays active much longer because it dodges the binding proteins that normally deactivate it. Drives muscle growth, protein synthesis, and satellite cell activation more potently than native IGF-1.
Research Overview Long R3 IGF-1 (IGF-1 LR3) is a recombinant modified form of insulin-like growth factor 1 engineered for dramatically enhanced potency and duration of action compared to the native growth factor. The modification involves two key structural changes: replacement of glutamic acid at position 3 with arginine (the "R3" designation), and the addition of a 13-amino-acid N-terminal extension peptide - together these alterations reduce the binding affinity of the modified IGF-1 for the six IGF binding proteins (IGFBPs) by more than 100-fold while preserving full agonist activity at the IGF-1 receptor. In the normal physiological context, approximately 98% of circulating IGF-1 is bound to IGFBPs (predominantly IGFBP-3 in a ternary complex with ALS), which regulate its bioavailability, tissue distribution, and half-life. By evading IGFBP sequestration, IGF-1 LR3 remains in its free, bioactive form with a functional half-life of approximately 20-30 hours - compared to roughly 15 minutes for the free fraction of native IGF-1. The IGF-1 receptor is a transmembrane tyrosine kinase receptor that, upon ligand binding, activates the PI3K/Akt and Ras/MAPK signaling cascades to promote cell survival, proliferation, and growth. In skeletal muscle, IGF-1 signaling stimulates protein synthesis through mTORC1 activation, promotes satellite cell proliferation and differentiation, and inhibits protein degradation by suppressing the FOXO-atrogene pathway. The dramatically increased potency and duration of IGF-1 LR3 compared to native IGF-1 has made it a widely used research tool in cell culture (where it is used as a media supplement to promote cell growth) and in preclinical investigations of muscle hypertrophy, tissue repair, and metabolic regulation. However, the same properties that make it potent also raise safety considerations - the lack of IGFBP buffering means that IGF-1 LR3 activity is less physiologically regulated, and concern exists about potential mitogenic effects in non-target tissues given IGF-1's known role in cell proliferation pathways.

Citations

Published findings on IGF-1 LR3 from peer-reviewed journals.

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