Comparison
Hexarelin vs. IGF-1 LR3
Two peptides side-by-side — identity, evidence base, legal status and known adverse events.
Identity
Category
Growth
Growth
CAS no.
140703-51-1
143045-27-6
Molecular weight
887.05 g/mol
9117.6 g/mol
Half-life
0.9 h
21 h
Sequence
His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2MFPAMPLSSLFVNGPRTLCGAELVDALQFVCGDRGFYFNKPTGYGSSSRRAPQTGIVDECCFRSCDLRRLEMYCAPLKPAKSAMechanism of action
Hexarelin
Hexarelin is a synthetic analog of the GHRP-6 family binding both the GH secretagogue receptor (GHSR-1a) and CD36. GHSR activation in the pituitary releases pulsatile growth hormone. Via CD36 in endothelium and myocardium, cardioprotective effects have been described in animal studies.
IGF-1 LR3
IGF-1 LR3 is a recombinantly produced variant of human IGF-1. Two changes define its properties: (1) at position 3, glutamic acid is replaced by arginine; (2) a 13-amino-acid sequence is added at the N-terminus ('Long'). Both modifications drastically reduce affinity for the six IGF-binding proteins (IGFBP-1 to -6) that normally bind native IGF-1 in the blood and regulate its availability at the receptor. As a result, a larger fraction of the molecule is freely available to bind the type-1 IGF receptor (IGF-1R) — the same receptor as native IGF-1. In preclinical models and cell culture, LR3 IGF-1 therefore acts as a more potent agonist than unmodified IGF-1. The downstream signalling pathway (PI3K/Akt and MAPK) is identical to that of IGF-1; the modification changes bioavailability, not the receptor target.
Evidence base
Highest evidence
Human trial
Animal model
Studies
4
4
of which in humans
3
0
Effects recorded
3
4
Open conflicts
0
1
Documented adverse events
1
1
Legal status
Full entries
Frequently asked questions
- What is the difference between Hexarelin and IGF-1 LR3?
- Hexarelin is classified as "Growth", while IGF-1 LR3 is classified as "Growth". Hexarelin: Synthetic hexapeptide of the growth-hormone secretagogue (GHRP) family. In the 1990s investigated as an acromegaly diagnostic and for GH deficiency. Not an approved medicine. IGF-1 LR3: Synthetic analogue of insulin-like growth factor 1 (IGF-1) carrying an arginine substitution at position 3 and a 13-amino-acid N-terminal extension. These modifications lower binding to IGF-binding proteins and extend its duration of action relative to native IGF-1. LR3 IGF-1 is primarily an established cell-culture reagent (serum-free media, bioprocessing); it is NOT an approved human medicine. Use in the bodybuilding grey market is described; as an IGF-1 analogue, LR3 IGF-1 falls under the WADA anti-doping prohibition. This page contrasts both neutrally and source-based — with no usage or dosing recommendation.
- Which peptide is better supported by science, Hexarelin or IGF-1 LR3?
- The highest available evidence level is "Human trial" for Hexarelin and "Animal model" for IGF-1 LR3. A higher evidence level means more robust data, but says nothing about suitability for an individual. The full body of evidence is on each peptide's own page.
- What is the legal status of Hexarelin and IGF-1 LR3 in Germany and the United States?
- Germany: Hexarelin — Unapproved, IGF-1 LR3 — Unapproved. United States: Hexarelin — Unapproved, IGF-1 LR3 — Unapproved. These are factual summaries with source and review date on the individual pages.