Insulin-like Growth Factor 1 Long Arg3 (IGF-1 LR3) is a synthetic analog of human IGF-1, a naturally occurring peptide hormone that plays a critical role in growth, repair, and metabolic regulation.
Structurally, IGF-1 LR3 consists of 83 amino acids, whereas native IGF-1 has 70 amino acids. IGF-1 LR3 has two additional key modifications: the substitution of arginine for glutamic acid at position 3, and the addition of a 13–amino acid extension at the N-terminus [1].
LGF
These alterations significantly extend its half-life and reduce its binding affinity to IGF-binding proteins, enhancing its biological availability in circulation.
By activating IGF-1 receptors, LGF-LR3 can initiate various intracellular signaling pathways, including PI3K/Akt/mTOR and MAPK/ERK, which are central to [2, 3]:
IGF-1 stimulates satellite cell activation and differentiation, key processes for muscle hypertrophy and repair following injury or intensive exercise [4]. However, these effects have yet to be studied in LGF-LR3 specifically.
LGF-LR3 enhances amino acid uptake, which can theoretically increase protein synthesis, and promotes the fusion of myoblasts into mature muscle fibers, contributing to muscle growth.
An animal study examined whether infusion of IGF-1 LR3 could improve growth and metabolic parameters in fetuses affected by placental insufficiency and fetal growth restriction (FGR) [5].
Fourteen fetal sheep were divided into two groups: one receiving IGF-1 LR3 infusion (1.17 μg/kg·h) and a control group receiving only the vehicle over one week. Glucose-stimulated insulin secretion (GSIS) tests were performed at the end of the treatment period to assess β-cell function.
Results showed:
IGF-1 LR3 did not enhance fetal growth or insulin dynamics in growth-restricted fetuses under these experimental conditions.
The observed decline in amino acid levels suggested possible increased tissue uptake or utilization, suggesting higher metabolic demand without adequate substrate availability.
Supplemental amino acids, glucose, or oxygenation may be necessary to optimize IGF-1-mediated growth responses in FGR scenarios.
IGF-1 LR3 has drawn increasing interest for its neuroprotective and cognitive-enhancing potential, reflecting the broader role of IGF signaling in the central nervous system (CNS).
Endogenous IGF-1 is widely expressed in both neurons and glial cells [6].
A study in 5XFAD mice (a transgenic model that rapidly develops amyloid-β (Aβ) pathology of Alzheimer’s disease) evaluated whether intranasal LR3-IGF-1 could mitigate cognitive decline and reduce AD-related pathology [7].
Wild-type and 5XFAD mice were treated intranasally with LR3-IGF-1 or vehicle solution from 3 to 10 months of age.
Results showed that LR3-IGF-1 treatment:
Although LR3-IGF-1 did not prevent cognitive decline, it produced measurable benefits in amyloid plaque remodeling and microglial function, implying a partial neuroprotective effect at the cellular level.
While human data remain limited, these findings point to IGF-1 LR3 as a promising anti-aging agent for the brain.
IGF-1 LR3 plays a pivotal role in energy balance and glucose metabolism, closely mirroring the physiological actions of insulin.
An animal study explored how short-term exposure to IGF-1 LR3 affects insulin secretion dynamics [8].
Ten fetal sheep were infused intravenously for 90 minutes with either IGF-1 LR3 (n = 5) or vehicle control (n = 5).
Results showed that:
Acute IGF-1 LR3 infusion transiently suppressed insulin secretion in vivo, without damaging β-cells.
This suggests that the inhibitory effects are reversible and may have therapeutic use for intrauterine growth restriction (IUGR) or metabolic modulation during development.
Research Use Only. All findings described above are derived from preclinical studies (animal models and in vitro experiments). IGF1-Lr3 is not approved by the FDA for any diagnostic or therapeutic use in humans. Genesis Peptides makes no claims regarding human clinical efficacy. This product is sold exclusively for laboratory research.
Every lot undergoes five independent assays before release. Results are published in the lot-specific Certificate of Analysis.
Every lot undergoes our 4-panel testing protocol: HPLC purity analysis, ESI-MS identity confirmation, LAL endotoxin screening, and amino acid analysis (for peptides >15 residues). Full analytical data is published in the Certificate of Analysis for each lot.
Lyophilized peptides should be stored at -20°C or below for long-term stability. Once reconstituted, peptides should be stored at 2–8°C and used within a reasonable timeframe depending on the specific compound. Avoid repeated freeze-thaw cycles. Always store in a dry environment away from direct light.
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No. All compounds sold by Genesis Peptides are strictly for in vitro and preclinical laboratory research purposes only. They are not approved for human consumption, therapeutic use, or diagnostic purposes. By purchasing, you confirm the products will be used solely for legitimate research applications.
A Certificate of Analysis (COA) is a document issued by our analytical laboratory that reports the results of all quality control tests performed on a specific lot of product. Each COA includes HPLC chromatograms, mass spectra, endotoxin results, and amino acid analysis where applicable. COAs are available in our COA Library for every lot we have shipped.
Yes. We offer volume pricing for universities, research institutions, and laboratories with recurring needs. Discounts begin at 10+ units and scale with volume. Contact our team for a custom quote tailored to your research requirements.
FOR RESEARCH USE ONLY — Products are sold exclusively for in vitro and preclinical laboratory research. Not for human consumption or administration. Not intended for diagnostic or therapeutic use. These statements have not been evaluated by the FDA.