Peptide Schedule
IGF-1 LR383 residuesMFPAMPLSSLFVNGPRTLCGAELVDALQFVCGDRGFYFNKPTGYGSSSRRAPQTGIVDECCFRSCDLRRLEMYCAPLKPAKSAEach bubble = one amino acid. Size = residue mass. Color = chemical class.IGF-1 LR3
Benefits
About IGF-1 LR3
IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a modified version of IGF-1 with a much longer half-life and greater potency. IGF-1 is the downstream effector of growth hormone — GH tells the liver to produce IGF-1, which then drives muscle growth (including hyperplasia: the creation of new muscle cells), recovery, and cellular regeneration. The LR3 modification makes it 2-3x more potent with a half-life of 20-30 hours vs 15 minutes for regular IGF-1.
Who Should Consider IGF-1 LR3
- Adults seeking lean mass and muscle hypertrophy support
- Experienced peptide users with prior GH or IGF-1 exposure
- Individuals recovering from muscle-wasting conditions (under medical supervision)
- Researchers studying IGF-1R-mediated growth pathways
What to Expect
Initial blood glucose fluctuations may occur. Mild pump sensation in trained muscles reported anecdotally. No visible body composition changes yet.
Increased muscle fullness and pumps during training. Water retention possible. Appetite may increase. Monitor blood sugar around dosing.
Noticeable improvements in recovery between sessions. Early lean mass gains become apparent. Localized muscle growth at injection sites reported in IM protocols.
Peak lean mass accrual and recovery benefits. Cycle off after 4-6 weeks to maintain IGF-1R sensitivity. Fat reduction may accompany lean tissue gains.
Dosing Protocol
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 20mcg | Daily |
| Moderate | 40mcg | Daily |
| Aggressive | 80mcg | Daily |
Note: Long-acting IGF-1 analog (LR3 = Long R3). Much more potent than regular IGF-1. Very low doses — use an insulin syringe for accuracy. Cycle 4-6 weeks on, 4 weeks off. Monitor blood sugar.
Pharmacokinetics
Source: Estimated 20-30h based on reduced IGFBP affinity vs native IGF-1 (t½ ~12-15h); Francis et al. 1995 PMID 7561636, Ballard et al. 1996 PMID 8708565
Loading the interactive decay curve.
Side Effects
Hypoglycemia (low blood sugar) — eat carbs around dosing. Joint pain, water retention. Long-term: potential organ growth. Use carefully and cycle.
Contraindications
- Active or history of any malignancy (IGF-1R activation may promote tumor proliferation)
- Pregnancy or breastfeeding
- Type 1 or poorly controlled type 2 diabetes (high hypoglycemia risk)
- Individuals under 18 or with open growth plates
- Known hypersensitivity to IGF-1 or related peptides
- Active acromegaly or elevated baseline IGF-1 levels
Drug Interactions
- Insulin — significantly increased hypoglycemia risk; concurrent use requires careful glucose monitoring
- Sulfonylureas and other hypoglycemic agents — additive blood sugar lowering effects
- Growth hormone (HGH) — synergistic IGF-1 axis stimulation; may amplify side effects including water retention and glucose dysregulation
- GLP-1 receptor agonists (semaglutide, tirzepatide) — both affect glucose homeostasis; monitor blood sugar if combining
- Corticosteroids — may blunt IGF-1 anabolic effects through catabolic opposition
Molecular Profile
Related Peptides
References
- Long R3 IGF-I infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGFBP concentrations in the guinea pig (J Endocrinol, 1995)PubMed 7561636
- Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection (J Endocrinol, 1996)PubMed 8708565
- Administration of IGF-I peptides stimulates proliferation of the small intestinal epithelium in rats (Am J Physiol, 1995)PubMed 8549937
- IGF-I, IGFBP-3, and cancer risk: systematic review and meta-regression analysis (Lancet, 2004)PubMed 15110491
- Use of Growth Hormone, IGF-I, and Insulin for Anabolic Purpose: Pharmacological Basis, Methods of Detection, and Adverse Effects (Endocr Rev, 2017)PubMed 29036389