1993 · FINDING
Tomas et al. — IGF-1 LR3 protein synthesis
LR3 analog showed 2–3x greater anabolic potency vs. native IGF-1 in rat models.
⚠ RESEARCH USE ONLY · NOT FDA-APPROVED FOR HUMAN USE · NOT MEDICAL ADVICE
MUSCLE & RECOVERYRESEARCH
IGF-1 LR3.
Extended-half-life IGF-1 — anabolic without GH
AKA · Long Arg3 IGF-1 · Insulin-like Growth Factor-1 LR3
MUSCLE & RECOVERYSUBCUTANEOUSINTRAMUSCULAR
A modified IGF-1 analog with an N-terminal extension and Arg³ substitution that makes it resist IGF binding proteins. Half-life jumps from ~15 minutes to ~24 hours — this is what makes it useful.
~20–30 hours
Half-life
3
Citations
2
Routes
1
Categories
70
Popularity
AT A GLANCE.
§ 01 · TL;DRTHE QUICK READ.
A modified IGF-1 analog with an N-terminal extension and Arg³ substitution that makes it resist IGF binding proteins. Half-life jumps from ~15 minutes to ~24 hours — this is what makes it useful.
IGF-1 is the downstream messenger of growth hormone. LR3 is a long-acting version that keeps the anabolic signal on for a full day.
Short cycles (4–6 weeks) common. Monitor fasting glucose.
WHAT IT MIGHT HELP WITH.
1
Direct IGF-1 receptor activation (bypasses GH axis)
2
Increased muscle protein synthesis
3
Satellite cell proliferation
4
Fat loss via insulin-mimetic effects
5
Used in wasting disease research
HOW IT WORKS.
§ 02 · MECHANISMIGF-1 is the downstream messenger of growth hormone. LR3 is a long-acting version that keeps the anabolic signal on for a full day.
IGF-1 analog with 13-residue N-terminal extension from bovine GH and glutamate-to-arginine substitution at position 3. Dramatically reduced IGFBP-3 binding extends plasma half-life ~30x vs. native IGF-1, maintaining constant IGF-1R activation.
WHO IT'S FOR
- ✓Researchers modeling anabolic pathways
- ✓Cachexia research
WHO SHOULD AVOID
- ✕Any cancer history
- ✕Diabetics without tight monitoring
- ✕Pregnancy
THE RESEARCH.
§ 03 · 3 STUDIES2003 · FINDING
Gillespie et al. — IGF-1 in cachexia
Sustained IGF-1 elevation attenuated muscle wasting in tumor-bearing mice.
2006 · FINDING
Yakar et al. — tissue-specific IGF-1
Systemic IGF-1 elevation improved body composition but raised cancer-model concerns.
DOSING PROTOCOL.
§ 04 · DOSINGTYPICAL RANGE
Short cycles (4–6 weeks) common. Monitor fasting glucose.
20–50mcg subcutaneous, 1–2x daily (reported research range)
FREQUENCY
Most-cited schedule
Once to twice daily
ROUTES
Delivery methods
SUBCUTANEOUS · INTRAMUSCULAR
HALF-LIFE
Steady state drives frequency
~20–30 hours
⚠ NOTE
These are reported protocols from research literature and practitioner accounts, not prescriptions. No FDA-approved human dose exists for research compounds. Anyone using IGF-1 LR3 should work with a qualified physician and source from a supplier providing third-party COAs.
FORMS AVAILABLE
- · Lyophilized vial, 1mg typical
⚠ RESEARCH INFORMATION ONLY · NOT MEDICAL ADVICE
SIDE EFFECTS & RISKS.
§ 06 · SAFETY•
Hypoglycemia
Common if dosed incorrectly · moderate
Eat before and after dosing
·
Injection site reactions
Common · mild
!
Theoretical cancer risk
Theoretical · serious
Sustained IGF-1 elevation studied in tumor models
!
Acromegalic changes long-term
Theoretical · serious
WHERE TO SOURCE
§ 07 · SUPPLIERPEAK LAB
PEPTIDES
PEPTIDES
SUPPLIER OF RECORD · 12 BATCHES PASSED
We tried nine suppliers across 2025 and kept picking PEAK LAB for IGF-1 LR3: 99.4% HPLC purity, COA on every batch, cold chain intact. Shop through our link and we earn a small commission — affiliate relationship is disclosed.
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