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IGF‑1 LR3
IGF-1 LR3 1 mg/3 mg – Long-acting IGF-1 analogue for research
Peptology Ltd. · Recovery and anabolic peptides
IGF‑1 LR3 1 mg/3 mg (Long R3 IGF-1) – a modified 83-amino-acid analogue of human insulin-like growth factor 1 (IGF-1): arginine at position 3 (“R3”) and a 13-amino-acid N-terminal extension (“Long”); research peptide. Purity 99%+, HPLC/MS report for every batch.
📦 The product is in our EU warehouse – delivery within 3–5 working days.
60,00 € · In stock
- 1mg — 60,00 €
- 3mg — 129,00 €
For research use only / Not a medicine
| Purity | >99% |
|---|---|
| Method | HPLC + LC/MS |
| Laboratory | Analiza Białek |
| Batch | 0226 |
Last updated: 02/10/2026
What is IGF-1 LR3 (Long R3 IGF-1)?
IGF-1 LR3 (Long R3 IGF-1) is a modified analog of human insulin-like growth factor 1 (IGF-1). Unlike natural IGF-1 (70 amino acids), IGF-1 LR3 has 83 amino acids: arginine instead of glutamic acid at position 3 (hence „R3") and an additional, 13-amino-acid extension at the N-terminus („Long"). These two structural changes significantly reduce binding to IGF-binding proteins (IGFBP), which translates into more of the free, active form of the peptide and a distinctly longer action.
This mechanistic difference is key. Most GH-axis peptides — like CJC-1295, GHRP-2 or Ipamorelin — act upstream in the cascade: they stimulate the pituitary to secrete GH, which only indirectly increases IGF-1. IGF-1 LR3 acts at the end of this cascade — it is itself a growth factor and directly stimulates the IGF-1 receptor, bypassing the GH step.
IGF-1 LR3 is studied in the context of muscle hypertrophy and regeneration, protein synthesis, cell proliferation and glucose metabolism. It is a research peptide — it holds no registration as a medicinal product in the EU. Because of its effect on glucose metabolism it requires particular caution in protocols (see the safety section). See also the other recovery and anabolic peptides in our category.
In the version offered by Peptology, IGF-1 LR3 is supplied as a lyophilized peptide with purity above 99% (HPLC/MS), confirmed by independent laboratory analysis (CoA for every batch). It is available in two vial formats — 1 mg and 3 mg — depending on the scale of the research protocol.
Available formats: 1 mg / 3 mg
IGF-1 LR3 is available in two lyophilized formats that cover different scales of research work.
1 MG
Standard format
Most often chosen for repeated cellular models and typical regenerative protocols.
3 MG
Enlarged format
For longer research series and protocols with higher peptide consumption.
All three formats have identical purity > 99% and the same laboratory certificate for the batch. The choice of size depends on the scale of the protocol, not on the concentration of the active substance.
How IGF-1 LR3 works — direct activation of the IGF-1 receptor
In the research literature, IGF-1 LR3 is described as a molecule that directly stimulates the IGF-1 receptor and triggers cellular growth pathways. The three features below together explain its strong and prolonged anabolic action.
IGF-1 RECEPTOR
Activates the IGF-1 receptor, triggering the PI3K/Akt (protein synthesis) and MAPK/ERK (cell proliferation) pathways — the basis of anabolic action.
REDUCED IGFBP BINDING
The Arg³ substitution lowers affinity for IGFBP-3 about 100-fold — more free, active peptide and a half-life of ~20–30 h.
HYPERTROPHY & SATELLITE CELLS
In research models it is associated with increased protein synthesis, nitrogen retention, activation of satellite cells and potential muscle hyperplasia.
Why acting „downstream" in the cascade matters
The growth axis works as a cascade: GHRH/GHRP → pituitary → GH → liver/tissues → IGF-1 → IGF-1 receptor. GHRH analogs (CJC-1295, Sermorelin) and GHRP secretagogues (GHRP-2, Ipamorelin) enter at the beginning of this cascade. IGF-1 LR3 enters at the very end — it is an exogenous growth factor and stimulates the IGF-1 receptor directly, independently of GH levels.
This makes IGF-1 LR3 a research tool for studying local, effector growth mechanisms, rather than the regulation of GH secretion. These data come from pharmacological studies and do not constitute a claim about the effect of the research-grade product.
Pharmacokinetics and pharmacodynamics of IGF-1 LR3
IGF-1 LR3 is an extended IGF-1 analog which, in the published data, is described as a molecule with a much longer half-life and higher biological activity than native IGF-1 — mainly thanks to limited binding to IGFBP.
- Biological half-life: about 20–30 hours (vs ~10–12 h for native IGF-1)
- Biological activity: about 2–3× higher than native IGF-1 in research models
- IGFBP binding: lowered ~100-fold (Arg³) — more of the free, active form
- Target: IGF-1 receptor (PI3K/Akt and MAPK/ERK pathways)
- Structure: 83 amino acids (Arg³ + 13-amino-acid N-terminal extension)
- Route of administration in protocols: subcutaneous or intramuscular, per the research protocol
IGF-1 LR3 vs CJC-1295 vs GHRP-2
The table below compares IGF-1 LR3 with two GH-axis tools acting „upstream" in the cascade. The key difference: IGF-1 LR3 is an effector (itself a growth factor, acting on the IGF-1 receptor), while CJC-1295 and GHRP-2 are GH-secretion stimulators (acting on the pituitary). That is why in studies they are combined, mapping the whole GH–IGF-1 axis. The data are scientific and comparative in nature.
| IGF-1 LR3 | CJC-1295 | GHRP-2 | |
|---|---|---|---|
| Class | Growth factor (IGF-1 analog) | GHRH analog | Ghrelin mimetic (GHRP) |
| Target | IGF-1 receptor (effector) | GHRH receptor (pituitary) | GHS-R1a receptor (pituitary) |
| Position in the cascade | End (downstream of GH) | Beginning (upstream of GH) | Beginning (upstream of GH) |
| Half-life | ~20–30 h | ~30 min (without DAC) | ~30 min |
| Main research area | Hypertrophy, regeneration, glucose | Pulsatile GH secretion | Strong GH pulse |
The pharmacokinetic values are approximate and come from the literature on IGF-1 and GH-axis analogs. The table is scientific and comparative in nature and does not constitute a direct head-to-head comparison or a claim about the effect of the research-grade product.
Research and preclinical data on IGF-1 LR3
IGF-1 LR3 is a research molecule and a laboratory reagent (widely used in cell cultures as a growth supplement) — it has not gone through a registration clinical program like prescription medicines. Below are the most important observations from the literature.
Structure and bioavailability of the free form
The Arg³ substitution and N-terminal extension lower affinity for IGFBP-3 about 100-fold. Because IGFBP normally bind and inactivate native IGF-1 within hours, their limited binding leaves more of the free, active form — which explains both the longer half-life and the higher biological activity.
Anabolic pathways
After activation of the IGF-1 receptor, two main pathways are triggered: PI3K/Akt, driving protein synthesis and inhibiting degradation, and MAPK/ERK, stimulating cell proliferation. In cellular and animal models this is associated with increased muscle mass, activation of satellite cells and tissue regeneration.
Effect on glucose metabolism
IGF-1 is structurally related to insulin and increases glucose uptake by cells. The prolonged half-life of IGF-1 LR3 means that this effect lasts for many hours — in research models this is associated with a risk of hypoglycemia, which makes glucose control an important element of every protocol.
Note: The information is presented for scientific and informational purposes and is based on pharmacological literature and preclinical data. It does not constitute medical advice, a recommendation for use or a claim about the effect of the research-grade product offered by Peptology.
IGF-1 LR3 profile at a glance
- Extended IGF-1 analog — acts directly on the IGF-1 receptor, downstream of GH in the growth cascade
- Half-life ~20–30 h and 2–3× higher activity thanks to limited binding to IGFBP
- Activation of the PI3K/Akt and MAPK/ERK pathways — protein synthesis and cell proliferation
- Activation of satellite cells and potential hyperplasia of muscle in research models
- Increased glucose uptake — requires control because of the risk of hypoglycemia
- Often combined with the GH axis (GHRH/GHRP, GH fragments) in protocols mapping the GH–IGF-1 axis
All information provided concerns pharmacological literature and preclinical data on IGF-1 LR3 and should not be interpreted as a promise of effect, an instruction for use or a claim about the effect of the research-grade product offered by Peptology.
Research dosing protocols
Important: The information below describes schedules used in research on IGF-1 LR3. It is provided for scientific and informational purposes and does not constitute a recommendation for individual use, medical advice or administration instructions. Because of its effect on glucose, protocols require blood glucose monitoring. The research-grade IGF-1 LR3 offered by Peptology is not a registered medicine.
Because of its long half-life, IGF-1 LR3 is used in protocols less frequently than short-acting peptides, subcutaneously or intramuscularly:
- 1 mg / 3 mg formats: for longer regenerative and cellular protocols
- Subcutaneous or intramuscular administration, per the research protocol
- Glucose control: recommended because of increased glucose uptake and the risk of hypoglycemia
In protocols mapping the whole GH–IGF-1 axis, IGF-1 LR3 is sometimes combined with GHRH analogs and GHRP secretagogues — e.g. CJC-1295 or Ipamorelin. These schedules come from the research literature and do not constitute a recommendation for self-administration.
Side effects and safety
The most important safety aspect of IGF-1 LR3 is its effect on glucose. Because the peptide increases glucose uptake, and its action lasts 20–30 hours, the risk of hypoglycemia is a real factor in research models. The other effects are usually mild and dose-dependent.
Frequently observed
- Mild hypoglycemia (hunger, tremor, sweating)
- Water retention
- Headache
- Tingling in the limbs
Less frequently described
- Fatigue or drowsiness
- Irritability
- Local injection-site reactions
- Transient joint pain
Requires particular attention
- Prolonged hypoglycemia (long half-life)
- Growth factor — caution in the context of cell proliferation
- No long-term safety data
In research models, the risk of hypoglycemia is reduced by controlling blood glucose and avoiding administration on an empty stomach. As a growth factor, IGF-1 LR3 requires caution in contexts related to cell proliferation. This information is scientific in nature and does not constitute an instruction for use.
Storage and reconstitution
IGF-1 LR3 is supplied as a lyophilized (freeze-dried) powder in a vial. In lyophilized form the peptide is stable at room temperature, protected from light and moisture — refrigeration before reconstitution is not mandatory. After reconstitution, stability depends on the solvent used, with Peptide Matrix Water™ significantly extending the peptide's lifespan.
- Before reconstitution: room temperature, in the original packaging, protected from light and moisture. A refrigerator is not mandatory.
- After reconstitution with Peptide Matrix Water™: stability in the refrigerator +2 °C to +8 °C for up to 60 days under appropriate laboratory conditions — the stabilizing formula extends the peptide's lifespan relative to standard solvents.
- After reconstitution with bacteriostatic or sterile water: stability in the refrigerator +2 °C to +8 °C for up to 28 days under appropriate conditions. Do not refreeze the reconstituted solution.
- Reconstitution: in a laboratory setting, Peptide Matrix Water™, bacteriostatic water or sterile water for injection is usually used, depending on the protocol.
- Volume: maximum 3 mL of solvent (capacity of a standard vial). For a precise calculation of volume and units, use the peptide calculator — particularly important for small doses of IGF-1 LR3.
- Homogenization: add the solvent slowly down the vial wall, without vigorous shaking — peptide bonds are sensitive to mechanical stress. Swirl gently, do not shake.
Laboratory tip: With your order, you can add Peptide Matrix Water™ to the cart — a stabilizing solution designed for working with reconstituted research peptides, including sensitive growth factors. More in the article Bacteriostatic water vs acetic acid vs matrix water.
Frequently asked questions about IGF-1 LR3
What exactly is IGF-1 LR3?
It is an extended analog of human IGF-1 (83 amino acids) with arginine at position 3 and an N-terminal extension. These changes reduce binding to IGFBP, giving a longer half-life (~20–30 h) and higher activity. It acts directly on the IGF-1 receptor. The results come from the research literature.
What is the main advantage of the LR3 format?
A much longer half-life and stronger action than native IGF-1. Native IGF-1 is rapidly bound by IGFBP and inactivated within hours; LR3 binds to them much more weakly, so it stays active longer.
How does IGF-1 LR3 differ from GH peptides like CJC-1295?
GH peptides (CJC-1295, GHRP-2, Ipamorelin) stimulate the pituitary to secrete GH, which indirectly raises IGF-1. IGF-1 LR3 is itself a growth factor — it acts at the end of the cascade, directly on the IGF-1 receptor, independently of GH. That is why in studies the two levels are often combined.
Why is glucose control important?
IGF-1 is related to insulin and increases glucose uptake. Because of the long half-life of LR3, this effect lasts many hours, which in research models is associated with a risk of hypoglycemia. That is why protocols include blood glucose monitoring.
Which format to choose — 1 or 3 mg?
Both have identical purity > 99% and the same batch certificate. 1 mg is the standard format; and 3 mg — for longer protocols with higher peptide consumption.
How is IGF-1 LR3 stored and reconstituted?
The lyophilized vial is stored at room temperature, protected from light and moisture. After reconstitution, stability depends on the solvent: with Peptide Matrix Water™ — up to 60 days in the refrigerator +2 °C to +8 °C; with bacteriostatic or sterile water — up to 28 days. Avoid refreezing.
Where to buy IGF-1 LR3 for research?
Peptology offers IGF-1 LR3 (1 / 3 mg) as a research peptide with confirmed purity above 99% (HPLC/MS) and independent laboratory analysis for every batch. Fast shipping, discreet packaging and certificates of purity with the product. For scientific background, also see the article Peptides — what they are, how they work, main categories and safety profile.
Related peptides in the Peptology catalog
Researchers working with IGF-1 LR3 often also consider GH-axis tools acting „upstream" in the cascade and ready-made complexes. Each of the products below has a certificate of purity above 99%:
CJC-1295 without DAC
GHRH analog (GH axis)
Ipamorelin
Selective GH secretagogue
GHRP-2
Ghrelin mimetic (GHS-R1a)
CJC-1295 + Ipamorelin
Ready-made GH-axis complex
Somatropin (HGH)
Recombinant growth hormone
Peptide Matrix Water™
Stabilizing solution for reconstitution
See the full catalog: Recovery and anabolic peptides · Solutions for peptides · Blog on peptide research
Research warning: IGF-1 LR3 (Long R3 IGF-1) is offered exclusively for scientific research and in vitro purposes. It is not a medicinal product, is not approved for use in humans or animals, and does not replace medical advice. All information comes from pharmacological literature and preclinical data and is provided for scientific and informational purposes; it does not constitute a claim about the effect of the research-grade product offered by Peptology.
Laboratory reconstitution
Laboratory protocol — reconstitution, research protocols, storage
Standardized protocol applicable to all research peptides in the Peptology catalogue. To calculate the solution concentration (mg/mL) for each vial, use the peptide reconstitution calculator.
60-second protocol
1. SOLVENT
2. RECONSTITUTION
Add the solvent down the side of the vial, without shaking, wait 10–15 min.
3. CALCULATION
Calculator → concentration mg/mL
4. STORAGE
+2 °C to +8 °C, up to 60 days with Peptide Matrix Water
Quick reference
| Parameter | Value |
|---|---|
| Form | Lyophilized powder |
| Solvent | Peptide Matrix Water |
| Reconstitution volume | 1–3 mL — maximum 3 mL (capacity of the standard vial) |
| Storage before reconstitution | Room temperature, protected from direct light (refrigeration not required) |
| After reconstitution | Up to 60 days at +2 °C to +8 °C with Peptide Matrix Water |
What you need
Precision pipette
Calibrated, 100–1000 µL — for accurately measuring the volume of solvent added to the vial.
70% alcohol swabs
Two swabs — to disinfect the peptide vial and the solvent vial.
Stabilized solvent for lyophilized peptides. Why this one.
Five rules for reconstitution
| ✅ Correct | ❌ Mistake |
|---|---|
| Disinfect the vial caps and the work surface with 70% alcohol; wear gloves | Working without disinfection |
| Add the solvent slowly along the vial wall | Direct jet onto the powder — foaming and denaturation |
| Gentle rolling between the palms | Shaking — foam, which denatures peptides |
| 10–15 minutes waiting at room temperature | Mechanical mixing or heating |
| Visual check: clear, particle-free | Working with a cloudy or discolored solution |
Calculating concentration
⚠️ Maximum 3 mL solvent. The standard vial does not accommodate larger volumes — do not exceed during reconstitution.
- Concentration (mg/mL) = mg in the vial ÷ mL of solvent
- Volume per sample (mL) = amount per sample (mg) ÷ concentration (mg/mL)
- 1 mg/mL = 1 µg/µL · 1 mL = 1000 µL
Reconstitution per vial — solvent: Peptide Matrix Water. Concentration after adding the solvent (1 mg/mL = 1 µg/µL):
| Vial | + 1 mL | + 2 mL | + 3 mL |
|---|---|---|---|
| 1 mg | 1 mg/mL | 0.5 mg/mL | 0.33 mg/mL |
| 3 mg | 3 mg/mL | 1.5 mg/mL | 1 mg/mL |
👉 For any vial and solvent volume — use the calculator. It calculates the concentration (mg/mL, µg/µL) and the volume per sample (mL, µL).
Storage
BEFORE RECONSTITUTION
Room temperature, protected from direct light, in original packaging. Refrigerator not required.
AFTER RECONSTITUTION
+2 °C to +8 °C, up to 60 days with Peptide Matrix Water. Discard any remainder after this period.
FREEZING
Not recommended. Freeze/thaw cycles degrade peptide structure.
Four mistakes to avoid
1. Shaking "to dissolve faster"
Foam = denaturation. Only gentle rolling between the palms.
2. Inappropriate solvent
For peptide stability use only sterile, specially formulated solvent — recommended Peptide Matrix Water.
3. Ignoring slight turbidity
Not fully clear = the sample does not meet the criteria for use.
4. Taking it out of the refrigerator "for an hour–two"
Short exposures add up and compromise stability.
Research status: All Peptology products are intended for laboratory and research use only. They are not medicinal products, not approved for human or veterinary use and do not substitute medical advice. The described protocol is standard laboratory practice for working with lyophilized peptides.
Shipping information
🚚 Shipping information
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Products in our warehouse – orders placed by 15:00 on working days are dispatched the same day, later orders on the next working day.
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Delivery with GLS to your address in 3–5 working days.
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Shipping costs €5 and is free from €50.
Frequently Asked Questions (FAQ)
What is the main advantage of the LR3 form?
The LR3 version has a much longer half-life and a more potent action compared with endogenous IGF‑1.
In what form is IGF-1 LR3 supplied and how should it be stored?
It is supplied as a lyophilized (freeze-dried) powder in a sealed vial. Store the unopened vial dry and protected from light, ideally at 2–8 °C. After laboratory reconstitution, keep the solution at 2–8 °C and use it within the period stated in the “Laboratory reconstitution” tab (up to 60 days with Peptide Matrix Water).
Is a prescription required?
No – the product is supplied for research purposes only.
Where can I buy IGF‑1 LR3 in Europe and what does it cost?
You can buy IGF‑1 LR3 in Europe online from Peptology, from 60,00 €. Delivery with GLS in 3–5 working days. Shipping is free from 50,00 €. Payment by card. Purity 99%+, with an HPLC report for every batch.
Laboratory Analysis
IGF-1 LR3 - 1mg - Batch - 0226 - Purity
IGF-1 LR3 - 3mg - Batch - 0226 - Purity
