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Growth & muscle

IGF-1 LR3

Also known as: Long R3 IGF-1

A long-acting analog of insulin-like growth factor 1, studied for muscle growth and recovery.

IGF-1 LR3 at a glance

NameIGF-1 LR3
Also known asLong R3 IGF-1
CategoryGrowth & muscle
TypePeptide
SequenceIGF-1 with an Arg3 substitution and a 13-amino-acid N-terminal extension
Typical dose~20–50 mcg
FrequencyDaily in research contexts
RouteSubcutaneous injection
Half-lifeExtended vs native IGF-1 (hours).

Overview

IGF-1 LR3 is a modified, longer-lasting version of IGF-1 — the downstream hormone through which growth hormone drives much of its muscle-building and repair effects. The modifications reduce its binding to carrier proteins, so more stays active for longer.

How it’s thought to work

  • Activates IGF-1 receptors to promote cell growth, protein synthesis, and repair.
  • Reduced binding-protein affinity extends its active window vs native IGF-1.

Researched uses

  • Muscle growth and hyperplasia research
  • Recovery and tissue repair

Commonly cited protocol

Typical dose~20–50 mcg
FrequencyDaily in research contexts
RouteSubcutaneous injection
NotesOften timed around training in anecdotal use.

Reconstitution

Often a 1 mg vial. 1 mg with 1 mL water = 1 mg/mL, so 50 mcg = 5 units on a U-100 syringe.

IGF-1 LR3 dosage calculator

The calculator below is pre-filled with IGF-1 LR3’s commonly cited vial size and dose. Adjust the vial amount, bacteriostatic water, or dose to match your own vial — it will show the exact insulin-syringe units to draw, the concentration, and how many doses the vial holds.

mg
50 mcg = 0.05 mg
mL
How much water you add is your choice — it doesn’t change your dose, only how many units you draw. Common:
Draw to
5 units
= 0.05 mL on a 1 mL (100 units) syringe
01020304050607080901005 ufill to the 5 u line on a 100-unit barrel
Concentration
1 mg/mL
Per unit
10 mcg/u
Doses per vial
20 × 50mcg
Volume
0.05 mL
📋 In plain English

Add 1 mL of bacteriostatic water to your 1 mg vial. That gives you about 20 doses of 50 mcg. For each dose, draw 5 units into a 100-unit insulin syringe.

⚠️ 5 units sits between the printed 2-unit marks on a 100-unit barrel — you'll have to eyeball it. Round to 6 u, or use "Help me pick water" to land on a whole mark.

See the full IGF-1 LR3 dosing chart (units for every dose & water amount), or open the full peptide calculator →

Cautions

  • Not approved for human use.
  • Can lower blood sugar (hypoglycemia risk).
  • Pro-growth signaling — significant caution with any cancer risk.

IGF-1 LR3 FAQ

What is IGF-1 LR3?

A long-acting analog of insulin-like growth factor 1, studied for muscle growth and recovery.

How does IGF-1 LR3 work?

Activates IGF-1 receptors to promote cell growth, protein synthesis, and repair. Reduced binding-protein affinity extends its active window vs native IGF-1.

What is IGF-1 LR3 used for?

Muscle growth and hyperplasia research; Recovery and tissue repair.

What is a typical IGF-1 LR3 dose?

~20–50 mcg, Daily in research contexts, Subcutaneous injection. This is a commonly cited figure for context only, not medical advice.

How do you reconstitute IGF-1 LR3?

Often a 1 mg vial. 1 mg with 1 mL water = 1 mg/mL, so 50 mcg = 5 units on a U-100 syringe.

What is the half-life of IGF-1 LR3?

Extended vs native IGF-1 (hours).

Related growth & muscle peptides

⚠️ Educational reference only — not medical advice. These compounds are largely research chemicals not approved for human use in most countries. Nothing here is a recommendation to obtain or administer any substance. Consult a qualified clinician.