IGF-LR3
A modified IGF-1 with extended half-life that directly stimulates muscle cell growth and differentiation.
Medically reviewed by Dr. Jonathan Snipes, MD. Last reviewed May 6, 2026.
What It Is
IGF-LR3 is a modified version of Insulin-like Growth Factor 1 with a longer active life. It works directly at the muscle cell level to promote growth.
How It Works
Unlike GH secretagogues that work upstream, IGF-LR3 binds directly to IGF-1 receptors on muscle cells, promoting hyperplasia (new cell growth) and hypertrophy (cell enlargement).
Who It's For
Advanced users seeking direct muscle growth support. Often used by athletes in recovery phases or those wanting to maximize lean tissue development.
Who Should Avoid It
Not for those with active cancer or diabetes. Requires careful blood sugar monitoring. Provider supervision essential.
Protocol & Pricing
OBP Pharmacy Price
$145/1mg
You pay pharmacy price. No markup.
Starting Dose
20-40mcg/day
Form
Injectable vial (5mL, 200mcg/mL, 1mg total)
Dosing Protocol
10-20 units (20-40 mcg) subcutaneous injection daily. At 200mcg/mL, 10 units = 0.10mL = 20mcg. Use for 4-6 week cycles. Monitor blood sugar.
Beyond Use Date
180 Days from compounding (USP <797>)
Optimal Balance Pharmacy assigns this date and prints it on your vial label. Always follow the label. Once a multi-dose vial is punctured, the in-use date on the label is shorter than the compounding date shown here.
Stacking Guide
Stacks Well With
Muscle growth peptide protocol
Read the IGF-LR3 protocol guide
Direct IGF-1 receptor agonist with no human muscle trial. Mechanism, conservative dosing, hypoglycemia risk, the cancer-signal concern, WADA S2 status, and the 503A pathway. Honest about how thin the evidence is.
Related Peptides
Independently tested
IGF-LR3 lab test reports
Every IGF-LR3 batch dispensed by Optimal Balance Pharmacy is independently tested by Eagle Analytical Services (FDA-registered, A2LA ISO 17025 accredited) for sterility (ScanRDI or Celsis) and bacterial endotoxin (USP <85>). The most recent report:
| Submission | Lot | Sample | Sterility | Endotoxin | |
|---|---|---|---|---|---|
| ETX-260804-0284 | LG342009739 | IGF-LR3 200MCG/ML 5ML | Pass | Pass <2 EU/mL / 400 EU/mL | Download |
Eagle Analytical Services is an independent FDA-registered laboratory, A2LA accredited to ISO 17025, based in Houston, Texas. They have no commercial relationship with RxPepsDirect. RxPepsDirect prescribes; Optimal Balance Pharmacy compounds and dispenses; Eagle tests every batch. Three separate companies. Browse our full quality program on the quality page.
How to get IGF-LR3 prescribed online
IGF-LR3 is available by prescription through a licensed telehealth visit and dispensed for human use by a named 503A pharmacy. That is what separates it from research-use-only vials sold without a prescription. There is no subscription and no membership, just a one-time visit fee.
- 1
Complete a $39 medical visit. Answer a short intake about your health history and your goals for IGF-LR3. The $39 fee is the only charge RxPepsDirect collects, paid once, not a recurring subscription.
- 2
A licensed provider reviews it. A US-licensed nurse practitioner or physician reviews your intake and, if IGF-LR3 is appropriate for you, writes a patient-specific prescription. The starting dose is typically 20-40mcg/day.
- 3
The pharmacy compounds and ships it. Optimal Balance Pharmacy, a 503A pharmacy in Texas, compounds IGF-LR3 and ships it pre-reconstituted by FedEx overnight in a reusable cooled case. Your fill is Injectable vial (5mL, 200mcg/mL, 1mg total), and you pay the pharmacy $145/1mg at wholesale, with no clinic markup, plus a $15 flat FedEx overnight shipping fee charged by the pharmacy.
RxPepsDirect prescribes IGF-LR3 in the 29 jurisdictions its medical team is licensed in. Start a $39 visit or browse the full Muscle Growth & Body Composition range. Comparing services first? See how RxPepsDirect stacks up against seven other providers in our best telehealth for compounded peptides comparison.
Common questions about IGF-LR3
- What is IGF-1 LR3?
- IGF-1 LR3 is a modified version of insulin-like growth factor 1 (IGF-1) with an extended half-life (~20 to 30 hours versus 10 to 20 minutes for native IGF-1) achieved by an arginine-leucine substitution at position 3 and a 13-amino acid extension at the N-terminus. The longer half-life makes it practical to dose subcutaneously once daily rather than by continuous infusion. IGF-1 mediates the anabolic effects of growth hormone on muscle, bone, and tendon.
- Does IGF-1 LR3 build muscle?
- IGF-1 LR3 increases protein synthesis and muscle satellite-cell activation in animal studies. In bodybuilding and athletic-performance contexts it is used at doses ranging from 20 to 100 mcg per day for 4 to 6 week cycles. Effects are most pronounced when paired with sufficient training stimulus and protein intake. Long-term continuous use is not recommended because IGF-1 LR3 can drive cell proliferation in tissues beyond muscle.
- How is IGF-1 LR3 dosed?
- Common protocols deliver 20 to 50 mcg per day for sport/athletic protocols, dosed subcutaneously once daily either in the morning or post-training. Optimal Balance Pharmacy compounds IGF-1 LR3 against RxPepsDirect prescriptions; the per-dose draw on your insulin syringe depends on the vial concentration printed on your label. Cycle 4 to 6 weeks on, then 4 weeks off.
- Where and when do I inject IGF-1 LR3?
- Subcutaneous injection into the abdomen, upper outer thigh, or back of the upper arm using a 31-gauge, 5/16-inch (8 mm) needle on a U-100 insulin syringe. Some athletes inject directly subcutaneously over the muscle group they trained that day; the localized effect is debated but the systemic effect from any subcutaneous site is the same.
- How is IGF-1 LR3 supplied?
- Compounded by Optimal Balance Pharmacy under a 503A patient-specific prescription. Ships pre-reconstituted and ready to inject in cold-chain packaging. Every batch is tested by Eagle Analytical Services; the Certificate of Analysis is published on this product page. Refrigerate per the printed label; do not freeze.