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Peptides · INSULIN-LIKE GROWTH FACTOR
IGF-1 LR3 1 mg
Lyophilized vial · 83 AA
Per vial
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SingleShips within 48 hours from San Antonio
UPS Ground · tracked + insured · released after independent lab testing
- Purity Guarantee. If a batch fails our ≥99% HPLC standard, full refund + replacement.
- Batch certificate in the COA library, anytime, free
- Same reorder price — forever, no upcharge
$91.99
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IGF-1 LR3 in brief
IGF-1 LR3 is a long-acting analog of insulin-like growth factor 1, used mainly in cell-culture and growth-signaling research. IGF-1 LR3 is not approved by the FDA for any use; it is a modified analog distinct from the FDA-approved form of IGF-1. Supplied for research use only.
— About this compound
IGF-1 LR3.
Class · Bioengineered IGF-1 variant with Long-R3 N-terminal extension (83 amino acids)
Origin. Developed at GroPep Limited (Adelaide, Australia) by Francis, Tomas, Wood, and colleagues in the early 1990s as a research tool with significantly extended half-life vs native IGF-1.
IGF-1 LR3 (Long R3 IGF-1) is a bioengineered analog of human insulin-like growth factor-1 carrying a 13-amino-acid N-terminal extension and an arginine substitution at position 3. The combined modifications dramatically reduce binding to IGF-binding proteins (IGFBPs).
Reduced IGFBP binding produces a substantially longer circulating half-life and higher receptor-available concentration than native IGF-1 at equivalent doses. The molecule is widely used in cell-culture research and preclinical anabolic-pathway studies.
— Common research applications
- IGF-1 receptor pharmacology
- Cell-culture anabolic research
- IGFBP binding kinetics
- Comparative IGF-variant studies
— Mechanism
How it's been studied.
IGF-1 receptor agonist with potency comparable to native IGF-1 at the receptor itself. The pharmacological distinction lies in the LR3 variant's reduced affinity for IGFBPs (particularly IGFBP-3), which extends free hormone availability in circulation and at target tissues.
Mechanism descriptions reflect findings reported in the preclinical and basic-research literature. They are not clinical conclusions and not statements of therapeutic effect.
— The Chemistry
The numbers, plainly.
CAS
—
Molecular weight
9111 Da
Formula
—
Sequence
—
Format
Lyophilized powder
Vial dose
1 mg
Purity (HPLC)
≥99%
Amino acids
83
Half-life
~5–6 hr (vs ~10–15 min for native IGF-1 in preclinical models).
Solubility
Physicochemical context only. Merit Sciences publishes no reconstitution or preparation procedures.
View lab results for IGF-1 LR3 → or browse every certificate.
— Why Merit
The supplier difference.
How Merit compares to the two alternatives most research buyers consider for IGF-1 LR3.
Comparison reflects published facility status and standard industry practice. Compounding pharmacy availability of research peptides varies by jurisdiction.
— How it's made
From compound to your shelf.
Every Merit batch follows the same documented path. Five steps, every one verifiable.
- 01
Sourcing
Compound starts as a research-grade API.
Active pharmaceutical ingredient sourced from FDA-registered manufacturers. Identity confirmed against reference standard before any compounding begins.
- API from FDA-registered manufacturers
- Identity verified against reference standard
- Chain of custody documented
- 02
Compounding
Sterile-filled in a US cleanroom.
Lyophilized in a cleanroom at our US facility. The powder format gives ≥24 months sealed stability — no cold-chain shipping required.
- Licensed US facility
- Lot-documented manufacturing process
- Lyophilized powder for transit stability
- 03
Verification
Every batch HPLC-tested.
Reverse-phase HPLC-UV (UV/MS for higher-MW peptides) confirms identity and purity for every batch before it leaves the lab. The chromatogram is archived.
- Reverse-phase HPLC, per-batch
- ≥99% purity floor — every batch
- Chromatogram archived for every batch
- 04
Release
The batch is released against an independent assay.
No batch ships until an independent laboratory has returned its identity and purity results and the certificate is published in the COA library.
- Independent laboratory on every batch
- Certificate published before sale
- Every certificate is in the public COA library
- 05
Dispatch
Ships from San Antonio in 48 hours.
Sealed vials with a QR code on the label that opens the COA library. Order before 2pm CT Monday–Thursday for same-day dispatch. UPS Ground, tracked + insured.
- 48hr dispatch from San Antonio, TX
- QR code on every vial label
- UPS Ground, tracked + insured
Every step above can be verified for any specific batch by emailing support@meritsciences.com with your order number.
— Research references
The published record.
Peer-reviewed work cited in the public scientific literature. Links resolve to PubMed or the publisher of record.
- 01
Insulin-like growth factor (IGF)-I and especially IGF-I variants are anabolic in dexamethasone-treated rats
Tomas FM, Knowles SE, Owens PC, et al. · Biochemical Journal · 1992
- 02
Use of insulin-like growth factor I analogues for the study of receptor binding and biological effects in adipocytes
Francis GL, Ross M, Ballard FJ, et al. · Journal of Molecular Endocrinology · 1992
Inclusion of a reference does not constitute a clinical claim or recommendation.
— Pairs Well With
Researchers stack this with.
The GH-Axis Stack
Secretagogue + downstream
Sermorelin paired with IGF-1 LR3: secretagogue plus downstream growth factor in the same shipment.
$160.99 · save 10%
— Go deeper
Mechanism, published research and peer-reviewed references for IGF-1 LR3, with no product attached.
Research review on The Assay, Merit’s editorial publication: IGF-1 LR3: What the Published Research Shows
— Common Questions
Got questions.
Is IGF-1 LR3 FDA-approved?+
IGF-1 LR3 is not approved by the FDA for any use; it is a modified analog distinct from the FDA-approved form of IGF-1. Supplied for research use only. IGF-1 and its analogues, which include IGF-1 LR3, are prohibited at all times under S2 of the WADA 2026 Prohibited List.
How is each batch of IGF-1 LR3 tested?+
Every batch is tested by an independent laboratory for identity and HPLC purity before it is listed, and Merit identifies batches by date rather than by lot number. Published certificates are in the COA library at meritsciences.com/coa, searchable by compound; the QR code on each vial opens its certificate. Search the COA library →
What does the published research on IGF-1 LR3 show?+
Francis (Journal of Molecular Endocrinology 1992) used IGF-I analogs to study receptor binding in adipocytes, and Tomas (Biochemical Journal 1992) reported that IGF-I variants were anabolic in dexamethasone-treated rats. Its main use today is as a cell-culture reagent. The IGF-1 LR3 monograph at meritsciences.com/library/igf-1-lr3 lists the references, and The Assay, Merit's editorial publication, reviews the evidence at theassay.co/articles/igf-1-lr3-research-review. Read the IGF-1 LR3 monograph →
What is IGF-1 LR3?+
IGF-1 LR3 (Long R3 IGF-1) is a bioengineered analog of human insulin-like growth factor-1 carrying a 13-amino-acid N-terminal extension and an arginine substitution at position 3. The combined modifications dramatically reduce binding to IGF-binding proteins (IGFBPs).
How does IGF-1 LR3 work?+
IGF-1 receptor agonist with potency comparable to native IGF-1 at the receptor itself. The pharmacological distinction lies in the LR3 variant's reduced affinity for IGFBPs (particularly IGFBP-3), which extends free hormone availability in circulation and at target tissues.
What class of compound is IGF-1 LR3?+
IGF-1 LR3 is classified as bioengineered IGF-1 variant with Long-R3 N-terminal extension (83 amino acids).
What is the reported half-life of IGF-1 LR3?+
~5–6 hr (vs ~10–15 min for native IGF-1 in preclinical models).
Why does Merit ship lyophilized?+
Lyophilized (freeze-dried) material is stable in sealed storage: ≥24 months at -20°C. Peptides held in solution degrade far faster, so every compound ships as a dry powder in a sealed vial.
What does "independently assayed" actually mean?+
Every batch is tested by a laboratory independent of the facility that made it, and the certificate is published before the batch is listed. You read the same identity and purity figures we do, which is what separates Merit from a reseller catalog.
How fast does it ship?+
48 hours from order to dispatch, Monday through Thursday. UPS Ground, tracked + insured. From San Antonio, TX, most US addresses receive within 3-5 business days.
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