LR3
Long-acting analog of IGF-1 with extended half-life due to amino acid substitutions. Studied in animal and cell models; no human muscle data.
Regulatory status (as of Sept 2026)
Not FDA-approved; prohibited by WADA as an IGF-1 analogue.
See the FDA peptide regulatory tracker · Read our July 27, 2026 dispatch on the FDA PCAC peptide vote3 studies referenced · Last reviewed Oct 1, 2026 · Reviewed by The Peptide Dispatch Editorial Team · How we research & label content
IGF-1 LR3 is a compound studied only in animals and lab experiments so far. Long-acting analog of IGF-1 with extended half-life due to amino acid substitutions.
| Half-life | Not established in published research |
|---|---|
| How it's given in studies | Subcutaneous or intramuscular |
| Research stage | Preclinical (animal) |
| Dosing | Published research: No published human dosing detailsRat i.v. bolus 2.6 µg/kg (distribution study); rat i.v. infusion 125 µg/kg/h (hemodynamics); s.c. injections in lactating mice; in vitro bovine follicle cultureCommunity-reportedCommunity-reported: 20–100 mcg, subcutaneous or intramuscular |
Published-research dosing is what was given in the cited studies (species and units as reported). Community-reported dosing is what users describe, not from clinical studies. Neither is a recommendation. Not medical advice.
Where each point comes from: Clinicalhuman trials and FDA labels Lab / animalrodent, cell and ex vivo studies Community-reporteduser experience and commonly used protocols, not from clinical studies
In plain terms: It is a modified form of the growth factor IGF-1 that is less held back by the proteins that normally bind IGF-1. IGF-1 analogue that binds the IGF-1 receptor but binds poorly to IGF-binding proteins, which is proposed to increase its bioavailability. In rats it cleared from the blood faster than IGF-I and was preferentially delivered to the intestine (Shoubridge 2003).
How to read this: Each item below is an effect observed in research subjects in the cited studies — think of Dexter, our stand-in research subject. These are findings from the literature, not results you should expect, and not medical advice.
Community-reportedCommonly reported doses range from 20 to 100 mcg (subcutaneous or intramuscular). This is not a recommendation.
Side effects reported in studies are listed separately below.
Community reports are anecdotal, vary widely in product quality and purity, and are not medical advice. Talk to a licensed provider.
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| Peptide | Half-Life | Route | Research Status |
|---|---|---|---|
| IGF-1 LR3 | No published PK data found | Subcutaneous or intramuscular | Preclinical (animal) |
| ACE-031 | ~12 days | Subcutaneous injection | Discontinued |
| Follistatin 344 | Unknown | Subcutaneous injection | Preclinical (animal) |
| IGF-1 DES | No published PK data found (des(1-3)IGF-I clears more rapidly than IGF-I in pigs/marmosets, but no published t1/2 value was found) | Intramuscular (site-specific) | Preclinical (animal) |
| MGF (Mechano Growth Factor) | No published PK data found | Intramuscular (site-specific) | Preclinical (animal) |
Values reflect figures reported in published research. Compare any peptides side-by-side →
This peptide belongs to the Muscle category. View All Muscle Peptides
Growth Hormone
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Dosing, half-life figures, and mechanism descriptions on this page are compiled from peer-reviewed published research, with the species and study type stated where reported. Figures labeled “Dosing used in published research” describe what was given in those studies and do not constitute dosing recommendations for any human use. Each cited paper is listed with DOI and PubMed links in the References section above. Found an error? Contact us.