Limited ResearchGrowth HormoneHealing & Recovery

IGF-1 LR3

Long R3 IGF-1

Modified Growth Factor Analog | Muscle Growth

Half-life

20-30 hours

Chain length

83 amino acids

Reference frequency

Once daily, or split AM/PM for higher doses

Research overview

DoseGear research brief

IGF-1 LR3 is a synthetic 83-amino acid analog of insulin-like growth factor-1 that has never been approved for human use. The N-terminal extension and R3 substitution reduce binding protein interaction, maintaining elevated free circulating levels with ~3x greater potency than native IGF-1.

Mechanism of action

Functions as a full IGF-1 receptor agonist activating PI3K/Akt/mTOR and MAPK/ERK pathways. The modifications prevent protein sequestration, maintaining elevated free circulating levels for extended anabolic effects.

Compound background

Development & research timeline

Study windows describe what researchers measured, not when an individual should expect a result.

Origin & development

Extended, Arg3-substituted synthetic IGF-I analog.

What it is researched for

Preclinical anabolic and cell-culture research through IGF-I-receptor signaling with reduced binding-protein interaction.

Research observation window

The source cites a seven-day animal treatment assessing body-weight recovery; no validated human response window is reported.

Reference data

Lyophilized vial injectable protocols

Not personalized dosing instructions

Only injectable vial references are shown. Nasal, topical, and unsupported non-vial schedules are excluded.

Research context	Amount	Frequency	Route
Beginner Protocol	20-30mcg	Once daily post-workout	SubQ/IM
Intermediate	40-60mcg	Once daily	SubQ/IM
Advanced	80-100mcg	Once or split AM/PM	SubQ/IM
Women's Protocol	10-20mcg	Once daily	SubQ/IM

Reference cycle

4-6 weeks maximum

Reference storage

Lyophilized: -20°C to -80°C; Reconstituted in acetic acid: 2-8°C for 1 year; Reconstituted in BAC water: use within 7 days

Safety context

Reported side effects

Hypoglycemia (lasting up to 30 hours) - CRITICAL
Water retention
Joint stiffness
Muscle soreness
Increased pump during workouts

Contraindications & cautions

NEVER approved for human use - research chemical only
Cancer history or undiagnosed growths
May cause organ hypertrophy (heart, intestines)
WADA prohibited - causes failed drug tests

Scientific references

01
Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats
Scientific citationInsulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats. Biochemical Journal (1992).
02
Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets
Scientific citationAttenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets. American Journal of Physiology - Regulatory, Integrative and Comparative Physiology (2023).
03
Insulin-like growth factor I preserves host lean tissue mass in cancer cachexia
Scientific citationInsulin-like growth factor I preserves host lean tissue mass in cancer cachexia. American Journal of Physiology (1992).
04
Circulating Insulin-like Growth Factor-I Concentrations and Risk of 30 Cancers: Prospective Analyses in UK Biobank
Scientific citationCirculating Insulin-like Growth Factor-I Concentrations and Risk of 30 Cancers: Prospective Analyses in UK Biobank. Cancer Research (2020).

This DoseGear profile combines published scientific literature with lyophilized-vial protocol references. Citations are provided for independent review.

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