IGF-1 LR3

Long R3 IGF-I · 83-residue IGF-I analogue for cell-culture and receptor research

≥ 99.0% · target, verify batch COACAS 143045-27-6RUO

Research statusLimited Research

Supplied form83-residue engineered, three-disulfide IGF-I protein analogue

Lead time14–21 days

IGF-1 LR3 — Lyophilized material; confirm released-lot appearance on the COA

Representative packaging image · verify the ordered lot

Decision summary

Key benefits

Research value: IGF-1 LR3 supports controlled studies of IGF1R signaling, IGFBP resistance, mitogenic/anti-apoptotic pathways, cell-line growth and bioprocess optimization
Animal anabolic, organ-growth and metabolic results do not establish human muscle growth, fat loss, recovery, tissue repair or anti-aging benefits.

Published research context is presented for literature orientation only. It is not a dosing, treatment or human-use instruction.

Qualification data

Specifications to confirm against the released lot

CAS: 143045-27-6
Formula: C₄₀₀H₆₁₉N₁₁₁O₁₁₅S₉ (three disulfides; reduced chain C₄₀₀H₆₂₅N₁₁₁O₁₁₅S₉)
Molecular weight: About 9111.6 Da
Appearance: Lyophilized material; confirm released-lot appearance on the COA
Purity: ≥ 99.0% · target, verify batch COA
Storage: Use the released-lot COA and stability statement for the supplied recombinant form. Define temperature, container closure, freeze-thaw allowance, adsorption controls, solvent, concentration and microbiological limits. Repligen instructions apply to its own qualified cell-culture formulations and are not automatically transferable to another lot.
MOQ: On request
Lead time: 14–21 days

Qualification matrix

Identity, purity and content are separate release questions.

Identity

Confirm the stated molecule and supplied form. Start with the matching batch COA; request sequence-level evidence only when the buyer's written procedure requires it and availability or a separate scope has been agreed.

Purity

Review RP-HPLC method conditions, wavelength, integration and related-peak handling. A percentage without the method is not enough.

Content

Net peptide content is not the same as gross lyophilized powder weight. Ask which assay supports the stated amount and whether water/counter-ion is addressed.

Stability

Define long-term storage and transit exposure separately. Cold-chain can be quoted when the buyer’s risk assessment requires it and adds cost.

Research context

What researchers study about IGF-1 LR3

IGF-1 LR3 (Long R3 IGF-I) is an 83-residue recombinant analogue of human IGF-I, engineered with a 13-residue N-terminal extension and an Arg substitution at position 3 to reduce binding to IGF-binding proteins. Its established commercial role is as a mammalian cell-culture supplement and research reagent. Direct evidence is predominantly in vitro and animal research; no qualifying interventional human trial of LR3 IGF-I was identified. FDA GSRS records the substance identity but explicitly states that UNII availability does not imply regulatory review or approval. This catalog material is RUO and not a finished dosage form.

Evidence contexts include recombinant cell-culture supplementation, IGF1R/IGFBP mechanism research, and animal studies of growth, endocrine feedback and tissue biology
Native IGF-I studies, epidemiology, veterinary case series and other analogues are indirect context and cannot establish LR3 human efficacy or safety.

Mechanism context

The question the literature is testing

IGF-1 LR3 activates the type 1 IGF receptor. Its N-terminal extension and Arg3 substitution markedly reduce affinity for IGF-binding proteins, increasing receptor availability in relevant in vitro systems. Downstream signaling can include PI3K/Akt/mTOR and MAPK/ERK pathways, but pathway activation does not establish a clinical outcome or lot-specific biological potency without a qualified assay.

Evidence map

Research routes and exposure context

Evidence tierAnalytical / laboratory context

Research areaGrowth-hormone axis research

Routes reported in sources

No administration route applies

Dose / exposure contextProtocol-specific; verify the cited primary source

Routes and exposure contexts summarize cited studies or approved finished-product labels. They are not instructions for administering this RUO material; no customer dose is provided.

Evidence boundaries

Compatibility, limitations and decision context

IGF-1 LR3 has no established administered-human safety profile
Mitogenic and glucose-regulatory activity creates material experimental hazards, and animal findings show strong species and protocol dependence
WADA prohibits IGF-1 and its analogues for athletes subject to the Code
Handle as an RUO recombinant growth factor under institutional risk controls; this record provides no injection, hypoglycaemia-management, cancer-screening or athletic-use advice.

Interactions reported in the literature

No human combination-use guidance is provided
Cell-culture co-supplementation with insulin is a process-development question requiring cell-line-specific titration and controls; it is not evidence for co-administration
Vendor stacking claims involving HGH, insulin, secretagogues, anabolic agents or other peptides are excluded.

Literature context is not a supplier release result or human-use instruction. Follow your institution's approved laboratory risk assessment.

Factory batch documentation

IGF-1 LR3 factory batch COAs

IGF-1 LR3 100 mcg Factory batch COA protected preview

IGF-1 LR3100 mcg · WHJLP-IGFL100-260629-E

IGF-1 LR3 1000 mcg Factory batch COA protected preview

IGF-1 LR31000 mcg · WHJLP-IGF1-260629-E

Representative records, refreshed periodically

Published COAs show representative factory batches and may not be the latest available. For a current quote or shipment, our sales team can confirm the applicable lot and provide its COA.

Independent testing, arranged on request

Third-party reports are not routinely published. If independent verification is required, we can agree the laboratory, method, acceptance criteria and remedy before testing. If the agreed specification is not met, an appropriate resolution—including a refund where applicable—can be discussed under the agreed terms. Unless otherwise agreed in writing, the buyer pays the cost of this optional testing.

Help reviewing your COA

Need help reading a factory COA or third-party report? Our sales team can clarify test items, specifications and how the results relate to the lot under discussion.

Ask for the current packet, not a generic certificate

Require the complete 83-residue sequence, correct disulfide connectivity, high-resolution intact and reduced mass, orthogonal identity, protein-content assay, aggregate and fragment profile, residual host-cell proteins/DNA where relevant, endotoxin or bioburden limits appropriate to the model, water and residual process impurities
HPLC area purity or intact mass alone does not establish correct folding or biological activity.

Released-batch COARP-HPLC result and method contextIdentity result appropriate to the moleculeWater / counter-ion context where relevantSDS and handling statementAdditional testing scoped on request

Available fills

Quote the fill and pack configuration you need

Reference SKUFillBase pack

IGF1-0100MCG100 mcg10 vials

IGF1-1000MCG1000 mcg10 vials

Handling

Storage in the lab and temperature during transit are different decisions

Use the released-lot COA and stability statement for the supplied recombinant form. Define temperature, container closure, freeze-thaw allowance, adsorption controls, solvent, concentration and microbiological limits. Repligen instructions apply to its own qualified cell-culture formulations and are not automatically transferable to another lot.

State destination, season, acceptable transit exposure and whether your protocol requires insulated or cold-chain service. Additional temperature-control cost is quoted explicitly.

Buyer FAQ

Terms to settle before the purchase order

Can a buyer arrange third-party testing?+

Yes. Testing must be performed by a mutually accepted, established specialist laboratory. Fee allocation, specification, sampling, method and acceptance rule must be agreed before testing; if an agreed independent result shows nonconformance, the remedy follows the signed order terms. Unless otherwise agreed in writing, the buyer pays the cost of this optional testing.

Does HPLC purity prove peptide content?+

No. Chromatographic purity describes the relative peak profile under a stated method. Identity, water, counter-ion, residual solvents and assay/content may require separate methods.

Is cold-chain shipping always required?+

Not always. Heat can accelerate degradation, especially during summer and long transit. Cold-chain reduces exposure but raises cost. State the destination and stability risk so the right service can be quoted.

How are payment terms handled?+

Available methods and milestones depend on order value, destination and project type. The pro forma invoice should state currency, bank details, fees, payment milestones and the release condition.

Why must the testing laboratory understand peptide chemistry?+

Free-base and salt forms, hydrophilic and hydrophobic sequences, aggregation and adsorption can change sample preparation and method suitability. Use a laboratory experienced with the molecule class.

External qualification references

WHO good storage and distribution practices IATA Temperature Control Regulations ISO/IEC 17025 laboratory competence 21 CFR 211.84 component testing and supplier COA controls

These are buyer-qualification references, not claims that this RUO material is regulated, certified or released under those frameworks. Applicability depends on the buyer's workflow and jurisdiction.

Selected sources

Literature behind the research context

Key sources: FDA GSRS UNII M9L22Y19H9; Repligen LONG R3 IGF-I product and FAQ/quality documents; WADA 2026 Prohibited List; Tomas et al. 1992 (PMID 1378742); the 1995 guinea-pig study (PMID 7561636); the 1999 satellite-cell study (PMID 10632630); and the listed IGF-1 signaling, anti-doping and tendon reviews. Evidence is labelled as direct LR3, parent-pathway, animal, veterinary or secondary context.

01
Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency
Journal of Molecular Endocrinology · 1992 · peer-reviewed original research
Open source
02
Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig
Journal of Endocrinology · 1995 · peer-reviewed original research (animal study)
Open source
03
Contribution of satellite cells to IGF-I induced hypertrophy of skeletal muscle
Acta Physiologica Scandinavica · 1999 · peer-reviewed original research (animal study)
Open source
04
Mechanisms of IGF-1-Mediated Regulation of Skeletal Muscle Hypertrophy and Atrophy
Cells · 2020 · peer-reviewed review
Open source
05
Insulin-Like Growth Factor-1 (IGF-1) and Its Monitoring in Medical Diagnostic and in Sports
Biomolecules · 2021 · peer-reviewed review
Open source
06
Doping and sports endocrinology: growth hormone, IGF-1, insulin, and erythropoietin
Revista Clínica Española (Barcelona) · 2023 · peer-reviewed review
Open source
07
Insulin-like growth factor-1 (IGF-1) empowering tendon regenerative therapies
Frontiers in Bioengineering and Biotechnology · 2025 · peer-reviewed review
Open source
08
Intralesional injection of insulin-like growth factor-I for treatment of superficial digital flexor tendonitis in Thoroughbred racehorses: 40 cases (2000-2004)
Journal of the American Veterinary Medical Association · 2011 · peer-reviewed original research (veterinary clinical case series)
Open source

Product FAQ

Questions buyers ask about IGF-1 LR3

What analytical package is appropriate for IGF-1 LR3?+

Confirm the complete 83-residue sequence, intact and reduced mass, peptide mapping or another orthogonal identity method, the three native disulfide bonds, chromatographic and electrophoretic purity, aggregates and fragments, and protein content. A qualified receptor or cell-based potency assay is needed if biological activity matters. If the lot is made in E. coli, set appropriate endotoxin, host-cell protein and residual host-cell DNA limits; do not infer the expression system from the product name alone.

Why can two molecular masses be reported for the same 83-residue sequence?+

The reduced free-thiol chain has composition C₄₀₀H₆₂₅N₁₁₁O₁₁₅S₉ and an average mass of about 9,117.6 Da. Formation of three intramolecular disulfide bonds removes six hydrogens, giving C₄₀₀H₆₁₉N₁₁₁O₁₁₅S₉ and about 9,111.6 Da; Repligen’s current freeze-dried product COA uses a 9,108–9,112 Da mass-spectrometry acceptance range. A COA should state whether a theoretical or measured value is average or monoisotopic and whether it refers to reduced or disulfide-bonded material.

Ready for review

Request a usable quote

Include fill, quantity, target purity/content, required methods, destination and timing.

B2B response target: 24 hours
Latest lot requested separately
Cold-chain priced when needed

Research Use Only. Human-use requests are not accepted.

Recent activity window

Recent confirmed orders including IGF-1 LR3

Recent Confirmed Orders2 · Last 30 daysView all

United States28.2 g2026-08-21

Tirzepatide 120 mg · P21 (P021) 5 mg · Semaglutide 50 mg · GLOW (BPC+GHK-Cu+TB) 70 mg · IGF-1 LR3 1000 mcg · GHK-Cu 100 mg · Cortagen 20 mg · Lemon Bottle 10 ml · Bacteriostatic Water 10 ml

Sweden4.7 g2026-08-16

Glutathione 400 mg · IGF-1 LR3 1000 mcg · Retatrutide 20mg + Tirzepatide 40mg 60 mg · PE-22-28 2 mg · Tirzepatide 2 mg · Somatropin (HGH 191 aa) 24 IU

IGF-1 LR3

Key benefits

Specifications to confirm against the released lot

Identity, purity and content are separate release questions.

What researchers study about IGF-1 LR3

The question the literature is testing

Research routes and exposure context

Compatibility, limitations and decision context

Interactions reported in the literature

IGF-1 LR3 factory batch COAs

Ask for the current packet, not a generic certificate

Quote the fill and pack configuration you need

Storage in the lab and temperature during transit are different decisions

Terms to settle before the purchase order

Literature behind the research context

Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency

Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig

Contribution of satellite cells to IGF-I induced hypertrophy of skeletal muscle

Mechanisms of IGF-1-Mediated Regulation of Skeletal Muscle Hypertrophy and Atrophy

Insulin-Like Growth Factor-1 (IGF-1) and Its Monitoring in Medical Diagnostic and in Sports

Doping and sports endocrinology: growth hormone, IGF-1, insulin, and erythropoietin

Insulin-like growth factor-1 (IGF-1) empowering tendon regenerative therapies

Intralesional injection of insulin-like growth factor-I for treatment of superficial digital flexor tendonitis in Thoroughbred racehorses: 40 cases (2000-2004)

Questions buyers ask about IGF-1 LR3

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