IGF-1 LR3
Long R3 IGF-1
A potent, long-acting IGF-1 analogue with strong anabolic signalling — and serious safety caveats.
Class
Long-acting insulin-like growth factor 1 analogue
Half-life
~20–30 hours (vs minutes for native IGF-1)
Evidence
Animal models
Animal models
Evidence comes primarily from rodent or other animal studies. Translation to humans is unproven.
Overview
IGF-1 LR3 is an engineered version of insulin-like growth factor 1 with an extended N-terminus and a substitution that dramatically reduces its binding to IGF binding proteins. The result is a molecule that is far more potent and far longer-lasting than native IGF-1, which is why it draws interest for muscle growth.
That same potency is the problem. IGF-1 is a central growth-and-proliferation signal, and sustained supraphysiologic levels are exactly the environment that can accelerate the growth of existing tumours. It also has meaningful hypoglycemia risk because of its insulin-like activity. Human evidence for bodybuilding use is essentially anecdotal; it is WADA-prohibited and research-only.
How it works
- Activates the IGF-1 receptor, driving muscle protein synthesis, cell proliferation, and hyperplasia.
- Reduced IGFBP binding gives it much higher bioavailability and a long half-life.
- Insulin-like activity promotes glucose uptake — the source of its hypoglycemia risk.
What the research shows
Researched effects
- Muscle hypertrophy and hyperplasia in animal models
- Increased protein synthesis and nutrient partitioning
- Anecdotal reports of localised and systemic muscle growth in humans
Limitations & what it won't do
- No controlled human efficacy or safety trials for performance use.
- Sustained IGF-1 elevation is a recognised tumour-promotion risk.
- Meaningful hypoglycemia risk; WADA-prohibited.
Dosing protocols
These ranges reflect published trials and community protocols. They are reference information, not a prescription. Doses are per injection unless noted.
Community protocol (high caution)
20–50 mcgDocumented for reference only. The tumour and hypoglycemia risks make this one of the higher-risk compounds in the catalog.
Reconstitution & measuring your dose
Handling
- Typical vial sizes
- 0.1 mg
- Suggested BAC water
- 1 mL
- Storage
- Lyophilised powder refrigerated at 2–8 °C, protected from light.
- After reconstitution
- Reconstituted: approximately 14–20 days refrigerated; IGF-1 analogues are relatively fragile.
Why 1 mL? A 0.1 mg (100 mcg) vial in 1 mL yields 100 mcg/mL — 20 mcg lands on 20 units of a U-100 syringe. The small total amount means precise measurement matters.
Dose calculator
Draw to
20units
= 0.2 mL · 1 mcg per unit
Concentration
100 mcg/mL
Doses per vial
5
Side effects
Common
- Hypoglycemia (shakiness, sweating, confusion)
- Injection-site reactions
- Joint or jaw aches
- Fluid retention
Serious / rare
- Severe hypoglycemia
- Theoretical promotion of existing tumours
- Organ growth with prolonged use
Contraindications & interactions
Do not use if you have
- Active cancer or current oncology treatment
IGF-1 is a direct proliferative signal. Active cancer is an absolute contraindication.
- Past cancer diagnosis (in remission)
Given the direct IGF-1 mechanism, any cancer history is a hard block pending oncology clearance.
- Pregnant, breastfeeding, or trying to conceive
No pregnancy safety data.
Use caution if you have
- Type 1 diabetes
Insulin-like glucose lowering requires very careful coordination.
- Type 2 diabetes or insulin resistance
Additive glucose-lowering; monitor closely.
- Hypoglycemia episodes
Direct hypoglycemia risk — a history of low blood sugar is a serious concern.
Medication interactions
- avoidInsulin — Additive, potentially severe hypoglycemia. Do not combine without medical supervision.
- avoidSulfonylureas — Additive hypoglycemia risk.
- cautionGrowth hormone (rhGH) — GH already raises IGF-1; adding exogenous IGF-1 pushes levels much higher.
What to monitor
- Blood glucose (before and after dosing)
- Any cancer screening appropriate for age
- Fluid status
Commonly combined with
References
Research & educational information only — not medical advice.
You must be 18 or older to use this site. The peptides described are presented as research chemicals intended for research purposes only. Most are not approved by the FDA for human use. Dosing ranges reflect what has appeared in the scientific literature or community protocols and are not prescriptions. Nothing here replaces evaluation by a licensed physician who knows your full medical history.
Want to know if IGF-1 LR3 fits your goals and history?
The assessment cross-checks your medical history and medications against this and every other compound before it recommends anything.
Start the assessment