What IGF-1 LR3 is
IGF-1 (insulin-like growth factor 1) is a hormone made mostly by the liver in response to growth hormone. It drives growth in many tissues and has insulin-like effects on blood sugar.
IGF-1 LR3 is an engineered version with one amino acid swapped and an extra 13 amino acid tail. Those changes keep it from being captured by the binding proteins that normally hold IGF-1 in check, so it stays active far longer. It was developed as a laboratory reagent for growing cells.
Mecasermin (Increlex) is an FDA-approved form of natural IGF-1 for a rare growth disorder in children. It is not IGF-1 LR3.
Regulatory status in 2026
IGF-1 LR3 has never been developed as a human drug. It is not approved, not on the compounding list, and was not part of the 2026 peptide reviews.
IGF-1 LR3 is developed for cell culture research.
IGF-1 LR3 is not among the peptides removed from Category 2 or reviewed by FDA's advisory committee.
Not approved, not compoundable, and prohibited at all times under WADA class S2 with other IGF-1 analogs.
Regulatory status can change. Check the sources linked at the bottom of this page before relying on anything here.
Claims vs. what the research shows
IGF-1 biology is well studied. IGF-1 LR3 as something people inject is not studied at all. Claims about it are extrapolated from cell, animal, and natural IGF-1 research.
Builds muscle directly.
IGF-1 signaling drives muscle growth in cell and animal studies. There are no human studies of IGF-1 LR3.
Animal or limited evidenceSafe at low amounts.
No human safety data exists at any amount.
Insufficient dataBurns fat.
No human evidence.
Insufficient dataStorage and stability
Peptides break down with heat, light, moisture, and repeated freezing and thawing. Degraded product is one common reason two vials of the "same" peptide behave differently. These are general peptide handling practices. Your supplier's certificate of analysis or label takes priority. Some suppliers specify a dilute acetic acid solution instead of bacteriostatic water for this one. Follow the label.
Sealed powder (lyophilized)
- Refrigerate at 36 to 46°F (2 to 8°C) for routine storage.
- Freezer is generally used for long-term storage.
- Keep in its original sealed vial, away from light.
- Let a cold vial reach room temperature before opening to limit condensation.
After reconstitution
- Keep refrigerated. Do not freeze.
- Protect from light. Clear glass lets it through.
- Opened multi-dose bacteriostatic water is typically discarded 28 days after first puncture.
- Log the mix date so you know the vial's age at a glance.
Light exposure is easy to overlook in a fridge door that opens dozens of times a day. VIALTIGHT is building stackable cases that block light from every side. See vialtight.com for updates.
Reconstitution math
Concentration is just the amount of peptide divided by the volume of water added. On a U-100 insulin syringe, 100 units equals 1 mL, so each unit is 0.01 mL. Enter what is on your vial label and what you added to see the concentration.
This shows concentration only. It is not a dosing recommendation. VialTracker runs this math for every vial you log and keeps it with the vial's history.
Safety flags
Low blood sugar is the main acute risk. IGF-1 lowers blood glucose the way insulin does. Shakiness, sweating, confusion, and loss of consciousness are possible. This is an emergency.
Cancer questions are real. IGF-1 promotes cell growth broadly, not only in muscle. Higher IGF-1 levels are associated with some cancers in population studies.
Product quality is unverified. Gray-market vials have been found underdosed, mislabeled, or contaminated. A certificate of analysis from the seller is not the same as independent testing.
Tested athletes. IGF-1 and its analogs are prohibited at all times under WADA class S2.
FAQ
Is IGF-1 LR3 the same as Increlex?
No. Increlex (mecasermin) is natural-sequence IGF-1, approved for a specific childhood growth disorder. IGF-1 LR3 is a modified laboratory version that has never been tested as a drug.
What does low blood sugar feel like?
Common signs are shakiness, sweating, a fast heartbeat, hunger, irritability, and confusion. Severe low blood sugar can cause seizures or unconsciousness and needs emergency care.
Does VialTracker tell me what to take?
No. VialTracker organizes the information you enter and runs the math. It does not recommend doses, products, or protocols.