Source comparison
IGF-1 LR3 Peptide vs Other IGF-1 Analogs
Native IGF-1 None (70 amino acids) >95% bound to IGFBPs 10–20 minutes Short-duration receptor studies requiring tight temporal control Limited by rapid clearance. Requires continuous infusion for sustained signaling IGF-1 LR3 R3E substitution + 13-aa N-termina
This comparison does not assign a generated winner or score.
- Native IGF-1
- None (70 amino acids)
- >95% bound to IGFBPs
- 10–20 minutes
- Short-duration receptor studies requiring tight temporal control
- Limited by rapid clearance. Requires continuous infusion for sustained signaling
- IGF-1 LR3
- R3E substitution + 13-aa N-terminal extension (83 amino acids)
- <5% bound to IGFBPs
- 20–30 hours
- Multi-day anabolic and metabolic studies in vitro and in vivo
- Industry standard for extended IGF-1R activation studies. Balances bioavailability with receptor specificity
- Des(1-3)IGF-1
- N-terminal tripeptide deletion (67 amino acids)
- 10–15% bound to IGFBPs
- 30–60 minutes
- Localized autocrine/paracrine studies in muscle and bone
- Higher IGF-1R potency but shorter half-life than LR3. Suited for acute signaling studies
- IGF-1 DES
- Same as Des(1-3)IGF-1
- High-potency receptor activation assays
- Approximately 10× more potent than native IGF-1 at the receptor level but cleared rapidly
- IGF-1 LR3 peptide occupies the middle ground between native IGF-1 (too short-lived for most multi-day protocols) and Des(1-3)IGF-1 (higher receptor potency but still requires frequent dosing). The 20–30 hour half-life of IGF-1 LR3 aligns with the typical 24–48 hour observation windows in cell culture experiments and the once-daily dosing schedules feasible in rodent models. Des(1-3)IGF-1 demonstrates approximately 10-fold higher binding affinity to the IGF-1 receptor due to removal of the N-terminal tripeptide that sterically hinders receptor docking, but its 30–60 minute half-life limits its utility in studies requiring prolonged receptor engagement. IGF-1 LR3 sacrifices some receptor potency for dramatically extended bioavailability. A trade-off that makes it the more widely adopted analog in contemporary research.