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A long-acting lab version of IGF-1, the hormone growth hormone works through.
Last reviewed Oct 7, 2026 · How we rate evidence · Report an error
IGF-1 is the hormone the liver makes in response to growth hormone. LR3 is an 83-amino-acid analog built for cell-culture work: one swapped amino acid plus a 13-amino-acid tail make it bind poorly to the proteins that normally hold IGF-1 in check, so it stays active longer. It has never been tested as a medicine in people. Use among bodybuilders is based on theory and anecdote.
Activates the IGF-1 receptor, which drives cell growth, protein building and glucose uptake. Because it largely escapes IGF-binding proteins, more of it stays free and active than with native IGF-1.
Evidence
1/5
Developed as a cell-culture reagent. No human clinical trials of LR3. Human data exists only for the approved native IGF-1 drug (mecasermin), a different product.
Half-life
Longer than native IGF-1 (often quoted as about 20–30 hours); not well studied in humans
Known as
Long R3 IGF-1, Long Arg3 IGF-1, LR3-IGF-1
Compare IGF-1 LR3 with: IpamorelinCJC-1295 (no DAC) + IpamorelinTesamorelinSermorelinor any other →
Little or noneAlmost no published research, or only lab studies.
Developed as a cell-culture reagent. No human clinical trials of LR3. Human data exists only for the approved native IGF-1 drug (mecasermin), a different product. How we rate evidence
Strongly drives muscle-cell growth in lab and animal studies.
Reported by bodybuilders; no controlled human data.
Its original use — a potent growth factor for cultured cells.
“Anecdotal” means reported by users, not shown in controlled trials. Sources
Not recommendations. These are commonly cited ranges, shown so you can see what real-world use looks like.
| Plan | Dose | Frequency | Duration | Route |
|---|---|---|---|---|
| Community Range 20–50 mcg; some go higher, which raises hypoglycemia risk. Eat carbohydrates around the dose. | 40 mcg | Once daily, often post-workout | 4–6 weeks, then a break | Subcutaneous or intramuscular |
Set up for IGF-1 LR3. Switch vial size any time. Educational math only, not dosing advice.
At a common mix of 1 mg of IGF-1 LR3 in 2 mL of water (0.5 mg/mL), these commonly reported doses come to the following on a U-100 insulin syringe (100 units = 1 mL). They are examples of the arithmetic, not recommendations.
| Reported plan | Dose | Draw to | Volume |
|---|---|---|---|
| Community | 40 mcg | 8 units | 0.08 mL |
Concentration (mg/mL) = vial mg ÷ mL of water; units = dose (mg) ÷ concentration × 100. A different vial size or amount of water changes every number above.
Amino Club sells IGF-1 LR3 as a research chemical. Its listings are research-use-only and not for human use; we show them for price tracking and their published lab reports.
Research-use-only listing — not for human use.
40% off through our link (code MYPEPSINFO applies automatically), until Dec 31, 2026.
| Size | Price | Per mg | Stock | Latest COA |
|---|---|---|---|---|
| 1 mg | $41.99 | $41.99 | In stock | 99.03% pure, lot IGF0002 ILS Labs, tested Jul 30, 2026 |
List price, checked daily since Oct 7.
| Oct 7, 2026 | $69.99 | |
| Oct 8, 2026 | $69.99 | |
| Oct 9, 2026 | $69.99 | |
| Oct 10, 2026 | $69.99 | |
| Oct 11, 2026 | $69.99 | |
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| Oct 18, 2026 | $69.99 | |
| Oct 19, 2026 | $69.99 | |
| Oct 20, 2026 | $69.99 | |
| Oct 21, 2026 | $69.99 | |
| Oct 22, 2026 | $69.99 | |
| Oct 23, 2026 | $69.99 | |
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| Oct 26, 2026 | $69.99 | |
| Oct 27, 2026 | $69.99 | |
| Oct 28, 2026 | $69.99 | |
| Oct 29, 2026 | $69.99 | |
| Oct 30, 2026 | $69.99 | |
| Oct 31, 2026 | $69.99 | |
| Nov 1, 2026 | $69.99 |
HPLC purity from each published lab report; lowest 99.03%.
| Jun 10, 2026 | 99.47% | lot IGF0001 |
| Jul 30, 2026 | 99.03% | lot IGF0002 |
Amino Club list prices as of Nov 1, 2026; sale prices include the 40% applied through our link. Multi-buy: 2+ units 5% off, 3+ units 7.5% off, 10+ units 40% off. Prices change; confirm on the listing.
An email when it’s back in stock, its price drops, a sale starts, or its FDA or WADA status changes.
Affiliate link: we may earn a commission at no cost to you. Disclosure
All IGF-1 LR3 lab reports, lot by lot →
Diluent: Bacteriostatic water, or 0.6% acetic acid as some sources suggest for stability. Bacteriostatic water (0.9% benzyl alcohol) — allows multiple draws from one vial.
Amazon affiliate links. Disclosure
Powder
Freezer / fridge
Keep sealed vial in the freezer (−20 °C) for long-term storage; fridge (2–8 °C) is fine for a few weeks. Keep dry and out of light.
After mixing
~21 days
Refrigerate at 2–8 °C. Never freeze after mixing. Keep upright, capped, and out of light.
Travel
Keep cool
Short trips at room temperature are generally fine for powder; keep mixed vials cold.
LR3 has never been approved. The only FDA-approved IGF-1 drug is mecasermin (Increlex, 2005) for severe primary IGF-1 deficiency in children — a different molecule. LR3 is sold as a research chemical.
Regulations change often — verify with the FDA, EMA, MHRA, Health Canada, TGA and WADA before acting.
No. Increlex is mecasermin, a copy of natural human IGF-1, made and tested as a drug. LR3 is a longer, modified analog made for lab cell culture and never tested as a medicine.
IGF-1 pulls glucose into cells much like insulin does. Dosing on an empty stomach raises the chance of a blood-sugar crash.
Mix with more water so each dose is a readable volume. At 0.5 mg/mL, 40 mcg is 8 units on a U-100 insulin syringe.
It depends on the mix. At a common mix of 1 mg of IGF-1 LR3 in 2 mL of water (0.5 mg/mL), 40 mcg is 8 units (0.08 mL) on a U-100 insulin syringe. The formula is dose in mg ÷ concentration in mg/mL × 100. Change the vial size or water in the calculator and the units update. This is math, not a dose recommendation.
Bacteriostatic water, or 0.6% acetic acid as some sources suggest for stability. Bacteriostatic water (0.9% benzyl alcohol) — allows multiple draws from one vial. A common mix is 1 mg + 2 mL, which gives 0.5 mg/mL. Less water makes a stronger mix and fewer units per dose; more water makes a weaker mix and more units. Pick the amount that lands your dose on an easy-to-read line.
Refrigerate at 2–8 °C. Never freeze after mixing. Keep upright, capped, and out of light. Plan on about 21 days once it is mixed, and discard it sooner if it turns cloudy or has particles. The calculator shows how long a vial lasts at your dose and flags a vial that outlasts its shelf life.
Evidence rating (1/5): Developed as a cell-culture reagent. No human clinical trials of LR3. Human data exists only for the approved native IGF-1 drug (mecasermin), a different product.
Legal status: LR3 has never been approved. The only FDA-approved IGF-1 drug is mecasermin (Increlex, 2005) for severe primary IGF-1 deficiency in children — a different molecule. LR3 is sold as a research chemical.
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