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Growth Hormone

IGF-1 LR3

Long R3 insulin-like growth factor-I, an extended-activity IGF-1 analogue

Long-acting IGF-1 analog research examining growth signaling, nutrient partitioning, and tissue adaptation.

Preclinical Evidence

Route

Subcutaneous research use.

Common format

1 mg vial

Research focus

IGF-1 signaling

Evidence level

Preclinical Evidence

Typical cycle

8 weeks

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IGF-1 LR3 in 30 seconds

Atlas Fast Read

What it is

Long R3 insulin-like growth factor-I, an extended-activity IGF-1 analogue

Why people care

Long-acting IGF-1 analog research examining growth signaling, nutrient partitioning, and tissue adaptation.

Human evidence

Preclinical Evidence — The exact compound or use is supported mainly by animal, in-vitro, or mechanistic work, or lacks meaningful controlled human efficacy evidence.

Biggest misconception

Key gaps include validated human dosing, pharmacokinetics, long-term safety, clinically meaningful efficacy, product standardization, and independent replication in well-controlled trials.

Bottom line

IGF-1 LR3 is scientifically interesting for IGF-1 signaling, muscle biology, but the current case is driven mainly by cell and animal data.

Overview

What is IGF-1 LR3?

IGF-1 LR3 is long R3 insulin-like growth factor-I, an extended-activity IGF-1 analogue. Long-acting IGF-1 analog research examining growth signaling, nutrient partitioning, and tissue adaptation.

Long R3 IGF-1 was engineered as a laboratory analogue of IGF-1 with reduced binding to IGF-binding proteins and prolonged activity. It is primarily a research reagent rather than an approved human therapeutic.

Mechanism

How it works

Activates the IGF-1 receptor and downstream PI3K-AKT-mTOR and MAPK pathways. Structural changes reduce binding to IGF-binding proteins and prolong bioactivity relative to native IGF-1.

Research areas

IGF-1 signalingmuscle biologyglucose metabolismtissue growth

Evidence

What does the evidence actually say?

Preclinical Evidence

The exact compound or use is supported mainly by animal, in-vitro, or mechanistic work, or lacks meaningful controlled human efficacy evidence.

01

Preclinical Evidence

02

Limited Human Evidence

03

Strong Human Evidence

Human evidence

IGF-1 LR3 does not have an established human therapeutic evidence base. Human medicine uses other IGF-1 preparations such as mecasermin; efficacy and safety data from those products should not be transferred directly to LR3.

Preclinical evidence

Cell and animal research shows potent IGF-1 receptor activation, anabolic signaling, glucose effects, and tissue growth. Its prolonged activity also raises safety concerns around hypoglycemia and growth signaling.

Knowledge gaps

Key gaps include validated human dosing, pharmacokinetics, long-term safety, clinically meaningful efficacy, product standardization, and independent replication in well-controlled trials.

Protocol

Research protocol

DoseFrequencyTimingCycle

Dose

Community research reference: 20–50 mcg/day. There is no approved human dosing standard for IGF-1 LR3.

Frequency

Once daily in the community protocol.

Timing

Community sources suggest morning or post-workout with food to reduce concern about glucose lowering; this is not clinically validated.

Route

Subcutaneous research use.

Cycle length

8 weeks

Reconstitution

Community reference: 1 mL per 1 mg vial = 1 mg/mL; actual stability depends on diluent and manufacturer instructions.

Storage

Keep lyophilized material frozen per supplier; reconstituted peptide refrigerated and protected from light, minimizing freeze-thaw.

Monitoring

Glucose, fasting insulin as indicated, IGF-1, edema, headache and hypoglycemia symptoms. Growth-factor exposure raises theoretical concern in active malignancy.

Protocols vary widely between sources. Investigational compounds are not approved therapies, and approved products should follow their official labeling. Nothing here is medical advice.

Safety

Safety, side effects, and precautions

Side effects

Potential GH/IGF-axis effects include edema, joint pain, tingling/carpal-tunnel-like symptoms, headache, flushing, increased appetite in some secretagogues, and worsening glucose tolerance. Injection-site reactions can occur.

Contraindications

No approved human contraindication profile exists for LR3. Because IGF signaling can drive tissue growth and lower glucose, active/suspected malignancy, recurrent hypoglycemia and serious proliferative disease are major concerns.

Interactions

GH/IGF signaling can alter glucose control, so insulin and other glucose-lowering therapy may require closer monitoring. Glucocorticoids can blunt GH effects; thyroid status can influence response. Formal interaction data are limited for research secretagogues.

Stacks

Common stacks

No well-supported stack is highlighted for this peptide yet.

Questions

FAQ

References

Sources

Atlas

The Atlas verdict

IGF-1 LR3 is scientifically interesting for IGF-1 signaling, muscle biology, but the current case is driven mainly by cell and animal data. Atlas would treat claimed benefits as hypotheses—not established human outcomes—and would put human safety, product quality, and controlled trials ahead of protocol optimization.

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