TEST SECTION STORE

£42.99

Purity: ≥ 99%

£42.99

TEST SECTION STORE

Name: TEST SECTION STORE
Brand: Pure Grade Labs
Price: 42.99 GBP
Availability: InStock

£42.99

Purity: ≥ 99%

£42.99

MUSCLE GROWTH - Hypertrophy and muscle building research

GROWTH PATHWAYS - Cell growth signalling research

STEM CELLS - Stem cell growth research

RECOVERY & REPAIR - Tissue healing research

IGF-1 LR3 (Long [Arg3] Insulin-Like Growth Factor-1) is a synthetic 83-amino-acid recombinant analogue of native human IGF-1. It differs from the 70-residue endogenous protein by two engineered modifications: a 13-amino-acid N-terminal extension derived from methionyl porcine growth hormone, and substitution of arginine for glutamic acid at position 3 of the mature IGF-1 sequence (hence "LR3" - Long Arg 3). Together, these modifications dramatically reduce the analogue's affinity for the six insulin-like growth factor binding proteins (IGFBP-1 through IGFBP-6) that normally sequester native IGF-1 in circulation, while preserving high-affinity binding to the IGF-1 receptor (IGF-1R).

The pharmacokinetic consequence of escaping IGFBP sequestration is substantial. Native IGF-1 has a circulating half-life of roughly 12-15 minutes when administered without its binding proteins, with most of the molecule rapidly partitioned to the bound pool. IGF-1 LR3 has been reported to remain bioavailable approximately 20-30 hours, with cell-culture stability greatly exceeding that of native IGF-1. Per-molecule potency at IGF-1R is approximately 2-3 times greater than native IGF-1 in vitro. Mechanistically, IGF-1 LR3 binds IGF-1R, a receptor tyrosine kinase expressed across muscle, bone, adipose, hepatic, and neural tissue, and activates two principal intracellular cascades: PI3K-Akt-mTOR (driving protein synthesis, anti-apoptotic signalling, and substrate uptake) and Ras-MAPK-ERK (driving cell proliferation and differentiation). In skeletal muscle, IGF-1R activation recruits satellite cells and promotes both hypertrophy (cell-size increase) and, in preclinical models, hyperplasia (fibre-number increase).

Engineered Modifications: 13-residue N-terminal extension (MFPAMPLSSL FVN) plus Arg substitution at position 3 of mature IGF-1. The combined effect is markedly reduced IGFBP binding while retaining IGF-1R affinity. Result: extended bioavailability and increased per-dose potency versus native IGF-1.

Research Context: Native recombinant IGF-1 (mecasermin / Increlex) holds FDA approval for severe primary IGF-1 deficiency (Laron syndrome). IGF-1 LR3 itself is not FDA-approved and exists primarily as a research and cell-culture tool. Used extensively in stem cell research, bioprocessing, and preclinical hypertrophy/regeneration work due to its superior in vitro stability.

Amino Acid Sequence: (83 Residues)MFPAMPLSSL FVNGPRTLCG AELVDALQFV CGDRGFYFNK PTGYGSSSRR APQTGIVDEC CFRSCDLRRL EMYCAPLKPA KSA

CAS Number: 946870-92-4

Peptide Length: 83 Amino Acids

Half-Life: ~20-30 hours

Form: Recombinant, Lyophilised

Biochemical Journal Preclinical / Animal: Tomas et al.: IGF-1 LR3 produces greater anabolic effects than native IGF-1 in protein-restricted rats without insulin-like glucose effects

Experimental Cell Research In Vitro / Human Myotubes: Jacquemin et al.: IGF-1 induces human myotube hypertrophy primarily through cell recruitment rather than per-cell protein accumulation

Journal of Clinical Endocrinology & Metabolism Long-Term Clinical / Human: Chernausek et al.: Long-term recombinant IGF-1 (mecasermin) safely produces sustained growth in severe primary IGF-1 deficiency (n=76)

https://pubmed.ncbi.nlm.nih.gov/8489506/

https://pmc.ncbi.nlm.nih.gov/articles/PMC7564605/

https://pubmed.ncbi.nlm.nih.gov/15302582/

https://pubmed.ncbi.nlm.nih.gov/17192294/

https://pubmed.ncbi.nlm.nih.gov/11915927/

https://pubmed.ncbi.nlm.nih.gov/36768692/

Every batch of IGF-1 LR3 supplied by Pure Grade Labs is accompanied by a Certificate of Analysis (COA) from an independent third-party analytical laboratory. The COA confirms identity, purity by HPLC, and absence of contaminants. Batch-specific documentation is linked below.

IGF-1 LR3 is supplied as a lyophilised (freeze-dried) recombinant protein with nine cysteine residues forming three intramolecular disulphide bonds critical to bioactivity. The protein is sensitive to heat, agitation, and freeze-thaw cycling. Follow the specifications below.

Temperature: -20°C Long-term storage. For short-term use (up to 4 weeks), 2-8°C is acceptable.

Light Sensitivity: Light-Sensitive. Store in original opaque vial. Avoid direct UV or prolonged exposure to light.

Shelf Life: 24 Months. Lyophilized, sealed, stored at -20°C. Batch expiry printed on vial label.

Allow the sealed vial to reach room temperature before opening to minimise condensation. The lyophilised cake is fragile; handle gently.
Use bacteriostatic water (BAC water) or, for cell-culture work, sterile dilute acetic acid (10mM) followed by buffer of choice. Add solvent slowly down the inside wall of the vial - do not inject directly onto the lyophilised cake.
Gently swirl until fully dissolved. Do not vortex or shake vigorously - agitation can disrupt the three disulphide bonds and denature the protein.
Inspect the solution: it should be clear and colourless with no visible particulates. Discard if cloudy, discoloured, or contains particulate matter.
Once reconstituted, store at 2-8°C protected from light. Use within 14 days. Avoid repeated freeze-thaw cycles - aliquot if longer-term storage of reconstituted material is required.

IGF-1 LR3 supplied by Pure Grade Labs is intended exclusively for in vitro research and laboratory use. While native recombinant IGF-1 is FDA-approved as mecasermin (Increlex) for severe primary IGF-1 deficiency, the LR3 analogue supplied here is a distinct engineered molecule, is not equivalent to any approved pharmaceutical product, and is not approved for human administration in any jurisdiction.

This product is not a drug, medicine, or supplement and must not be used as such outside of a licensed clinical or research context.
Pure Grade Labs makes no claims regarding therapeutic or clinical efficacy in humans for any use of this research compound.
IGF-1 LR3 is prohibited at all times in sport by WADA under the S2 Peptide Hormones, Growth Factors, Related Substances and Mimetics category. Athletes subject to drug testing must be aware of this classification.
Hypoglycaemia is a known dose-limiting adverse event across the IGF-1R agonist class due to insulin-receptor cross-activation and effects on glucose disposal. Other reported adverse signals include lymphoid tissue hyperplasia, lipohypertrophy at injection sites, and theoretical pro-proliferative effects on neoplastic tissue via IGF-1R signalling.
IGF-1 LR3 is contraindicated as a research subject for any individual with a history of cancer, active malignancy, diabetic retinopathy, or pregnancy.
Purchasers are solely responsible for compliance with all applicable laws and regulations in their jurisdiction.

All product information, research summaries, and study citations presented on this page are provided for informational context only and do not constitute medical advice, endorsement of any treatment, or recommendation for human use.