IGF-1 LR3 Pharmacokinetics
IGF-1 LR3 half-life, absorption, routes of administration, and clearance.
Half-Life & Dosing Cadence
IGF-1 LR3 has a reported elimination half-life of ~20-30 hours. The half-life is the time it takes for blood levels to fall by half, and it's the single biggest driver of how often you dose. That's why the typical schedule lands around 1x daily at 20–50 mcg — frequent enough to keep levels in a useful range without stacking up. Shorter half-lives mean more frequent dosing and faster clearance if you stop; longer ones mean steadier levels but a slower washout.
Administration & Absorption
IGF-1 LR3 is administered by subcutaneous injection (into the fat layer just under the skin) and intramuscular injection (directly into muscle). The primary route is subcutaneous. Subcutaneous delivery is absorbed steadily from the fat depot, giving smoother peaks than intramuscular dosing. Whichever route you use, rotate sites and follow sterile technique.
Reconstitution & Handling
IGF-1 LR3 ships as a lyophilized (freeze-dried) powder that you reconstitute before use — a common starting point is a 1 mg vial with 1 mL of bacteriostatic water. Add the water slowly down the vial wall, swirl (don't shake), and let it fully dissolve. Reconstituted peptide is refrigerated and used within its stability window; unmixed powder keeps far longer when stored cold and dark. Always confirm exact dosing math against your own vial and concentration.
Onset & Clearance
Because of its ~20-30 hours half-life, IGF-1 LR3 reaches steady levels after a few consistent doses and clears the system within roughly four to five half-lives once you stop. Track how you respond over a defined block rather than judging any single dose, and give the compound enough consistent days before deciding whether it's working. This is educational information, not medical advice — review your protocol with a clinician.
Physicochemical and PK profile
- Molecular Formula
- C400H625N111O115S9
- Molecular Weight
- 9,111 g/mol
- CAS Number
- 946870-92-4
- Half-Life
- 20-30 hours (approximately 2-3 times longer than native IGF-1)
- Solubility
- Soluble in water and dilute acidic buffers (0.1 M acetic acid); reconstitute in sterile water or 10 mM HCl
- Storage
- Store lyophilized powder at -20°C to -80°C. Reconstituted solution at 4°C for up to 1 month. Avoid repeated freeze-thaw cycles. Add carrier protein (0.1% BSA) to dilute solutions to prevent adsorption loss.
References
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- Insulin-Like Growth Factor-1 (IGF-1) and Its Monitoring in Medical ... · Bailes J, Soloviev M · 2021
- IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep. · White A, Stremming J, Wesolowski SR et al. · 2025
- IGF-1 Has Plaque-Stabilizing Effects in Atherosclerosis by Altering ... · von der Thüsen JH, Borensztajn KS, Moimas S, van Heiningen S, Teeling P, van Berkel TJ, Biessen EA · 2011
- Revolutionary decellularized Alstroemeria stem-based nerve conduit integrated with GelMA and controlled IGF-1 LR3 release for enhanced rat sciatic nerve regeneration. · Yavuz E, Sağır MS, Ercan A et al. · 2025
- Recombinant expression of IGF-1 and LR3 IGF-1 fused ... - PubMed · Lu Z, Liu N, Huang H, Wang Y, Tu T, Qin X, Wang X, Zhang J, Su X, Tian J, Bai Y, Luo H, Yao B, Zhang H · 2023
- Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets. · White A, Stremming J, Brown LD et al. · 2023
- Use of Growth Hormone, IGF-I, and Insulin for Anabolic Purpose: Pharmacological Basis, Methods of Detection, and Adverse Effects · Anderson LJ, Tamayose JM, Garcia JM · 2018
- IGF-1 infusion to fetal sheep increases organ growth but not by stimulating nutrient transfer to the fetus. · Stremming J, Heard S, White A et al. · 2021
- The IGF-1/PI3K/Akt Pathway Prevents Expression of Muscle Atrophy ...
- Reduced glucose-stimulated insulin secretion following a 1-wk IGF-1 infusion in late gestation fetal sheep is due to an intrinsic islet defect. · White A, Stremming J, Boehmer BH et al. · 2021
- Performance Enhancing Hormone Doping in Sport - Endotext - NCBI