IGF-1 LR3

IGF-1 LR3 is a recombinant analog of human IGF-1 with an arginine substitution at position 3 and a 13-amino-acid N-terminal extension. It is a laboratory reagent used primarily in cell culture media.

The structural modifications greatly reduce affinity for IGF-binding proteins, extending circulating half-life relative to native IGF-1 and increasing free ligand available to the IGF-1 receptor. Receptor activation drives PI3K-Akt-mTOR signaling and MAPK-mediated proliferation.

Store the sealed lyophilized vial at 2-8 °C, protected from light; brief exposure to room temperature during shipping is generally tolerated. Refrigerate after reconstitution at 2-8 °C and use within the period supported by stability data for the substance (typically 2-4 weeks). Avoid repeated freeze-thaw cycles: each cycle increases the risk of aggregation and hydrolysis of the peptide bond. Do not shake the vial; swirl gently and direct the liquid stream against the glass wall rather than at the powder cake.

• Sealed lyophilized vial, stored as supplied
• Bacteriostatic water (0.9% benzyl alcohol) for reconstitution
• Insulin syringes (29-31G, 0.5 mL / 100 units)
• Reconstitution syringe (1-3 mL, 21-23G needle)
• 70% isopropyl alcohol swabs
• Sharps container for used needles
• Labels and a logbook for batch, date and volume

Cell and animal research reports increased protein synthesis, satellite cell activation and hyperplasia. Because IGF-1 signaling is mitogenic and cross-reacts with the insulin receptor at higher concentrations, hypoglycemia and a theoretical increased proliferation risk are among the documented risks. Human safety data for the LR3 analog are lacking.

Wash your hands, then disinfect the vial septum and the injection site with 70% isopropyl alcohol and allow both to air dry. Draw up the intended volume, remove air bubbles and pinch a subcutaneous skin fold. Insert at a 45-90° angle depending on fat thickness, aspiration is not required for subcutaneous administration, and inject slowly. Withdraw the needle, apply light pressure and discard the needle in a sharps container. Rotate injection sites systematically (abdominal quadrants, flanks, thighs) to prevent lipohypertrophy and local irritation.

Peptide research protocols are studied against a background of adequate protein intake (approximately 1.6-2.2 g/kg/day in the training literature), consistent sleep of 7-9 hours, and controlled training load. Sleep deprivation and chronic psychological stress both dampen growth hormone pulsatility and disrupt tissue remodeling, complicating the interpretation of any observed effect. Alcohol, smoking and large caloric deficits are likewise documented modifiers of recovery outcomes.

1. Tomas F.M. et al. Insulin-like growth factor-I variants with reduced binding-protein affinity. Biochem J, 1993.
2. Philippou A. et al. The role of the insulin-like growth factor 1 in skeletal muscle physiology. In Vivo, 2007.
3. Clemmons D.R. Metabolic actions of IGF-I in normal physiology and diabetes. Endocrinol Metab Clin, 2012.