IGF-1 LR3 is sold as a research vial in 0.1 mg and 1 mg sizes and discussed as though it had a dose. It does not have one in the sense the word usually carries: no human study has administered it, no registry holds a trial of it, and no label anywhere states an amount. What exists is a set of animal infusion rates, an approved label for a different molecule, and two published analyses of what the vials on the market actually contain. This page reports all three, converts every figure into the syringe units a U-100 insulin syringe reads, and states where each number came from. It reports and does not recommend.
The IGF-1 LR3 calculator runs the same sums for any vial and volume, the water-and-concentration side is worked through on the IGF-1 LR3 reconstitution page, and the all-compounds chart carries the one-line version beside every other compound.
What exists, and what does not
A census, run on 2026-09-20 and reproducible. PubMed returns 78 records for the analogue's name forms in title or abstract — "long r3 igf", "long-r3-igf", "longr3" and "igf-1 lr3" — of which 25 carry the human tag. Reading those 25 finds cell-culture experiments where the analogue is a reagent in the growth medium, two doping-control method papers, and reviews; none administered it to a person. ClinicalTrials.gov returns nothing for any of those name forms. DailyMed returns no label. The French anti-doping agency's laboratory states the regulatory position in a sentence: the analogues "were never approved for use in humans".
That is the whole basis on which a dose figure could rest, and it is empty. What fills the gap on vendor pages is a range — 20 to 100 mcg a day, in cycles of four to six weeks — with no source attached to it.
The animal figures, which are the only administration data
| Study | Subjects | Dose and route | What it reported | Opened |
|---|---|---|---|---|
| Am J Physiol Endocrinol Metab, PMID 39679943 (2025) | Growth-restricted fetal sheep, n = 7 | 1.17 mcg/kg/h infusion, 1 week | No difference in body weight, insulin, glucose or glucose-stimulated insulin secretion; amino acids fell | 2026-09-20 |
| Am J Physiol Endocrinol Metab, PMID 33938236 (2021), rate as stated by PMID 39679943 | Normal fetal sheep | 6.6 mcg/kg/h infusion, 1 week | Higher body weight, lower insulin concentrations and reduced glucose-stimulated insulin secretion, traced to an intrinsic islet defect | 2026-09-20 |
| J Dev Orig Health Dis, PMID 37114757 (2023) | Fetal sheep | 90-minute infusion | The attenuated insulin secretion did not persist in isolated islets | 2026-09-20 |
| Am J Physiol, PMID 9252489 (1997) | Neonatal calves | 50 mcg/kg/day subcutaneously or orally, 7 days | Plasma analogue rose after subcutaneous but not oral administration; endogenous IGF-1 and growth hormone fell | 2026-09-20 |
| Domest Anim Endocrinol, PMID 10370861 (1999) | Beef heifers losing weight | Intravenous infusion | A tendency for whole-body and skeletal muscle protein to be conserved | 2026-09-20 |
Two things in that table are worth reading twice. The infusion rates are continuous, so the daily amount is the rate times 24: 6.6 mcg/kg/h is 158 mcg/kg/day. And the most recent study is negative — a week of the analogue did not improve growth in the fetuses that were growth-restricted, which is the population it was proposed for.
Applying those per-kilogram rates to a 70 kg adult gives 3.5 mg a day from the calf figure and 11.1 mg a day from the fetal-sheep figure. Those numbers are set out to show the size of the gap, not as human amounts: a rate measured in a fetal lamb or a week-old calf does not transfer to an adult of another species by multiplication, and nothing published allows the conversion to be done properly. Against them, the circulating 20 to 100 mcg a day is between 35 and 175 times smaller than the calf rate alone.
The only labelled IGF-1 dosing is a different molecule
Mecasermin is recombinant human IGF-1 — the natural sequence, not the analogue — and it is approved for severe primary IGF-1 deficiency. Its label sets 0.04 to 0.08 mg/kg twice daily to start, increasing by 0.04 mg/kg per dose to a maximum of 0.12 mg/kg twice daily, from a solution of 40 mg in 4 mL.
That concentration, 10 mg/mL, is the useful part here, because the label converts its own doses into insulin-syringe units and almost nothing else in this field does:
Weight (kg) × Dose (mg/kg) × 1 mL/10 mg × 100 units/1 mL = units/injection
At 10 mg/mL one U-100 unit holds 100 mcg, and the formula reduces to milligrams times ten. A 20 kg child at 0.08 mg/kg draws 1.6 mg, which is 16 units; at the 0.12 mg/kg maximum, 24 units. The relevance to a research vial is limited and specific: it shows what a regulator considers a dosing instruction to contain — a per-kilogram amount, a frequency, a concentration, and the arithmetic that turns them into a syringe reading.
The arithmetic per vial
The calculator's presets for this compound are the 0.1 mg and 1 mg vials. One U-100 unit is a hundredth of a millilitre (MedlinePlus, "Giving an insulin injection", reviewed 2024-07-21). The right-hand columns are the range circulating for the vial.
| Vial and water | mcg/mL | mcg per unit | 20 mcg | 50 mcg | 100 mcg |
|---|---|---|---|---|---|
| 0.1 mg in 0.5 mL | 200 | 2 | 10 units | 25 | 50 |
| 0.1 mg in 1 mL | 100 | 1 | 20 | 50 | 100 |
| 0.1 mg in 2 mL | 50 | 0.5 | 40 | 100 | 200 |
| 1 mg in 1 mL | 1,000 | 10 | 2 | 5 | 10 |
| 1 mg in 2 mL | 500 | 5 | 4 | 10 | 20 |
| 1 mg in 3 mL | 333 | 3.33 | 6 | 15 | 30 |
| 1 mg in 5 mL | 200 | 2 | 10 | 25 | 50 |
The two extremes are both awkward, in opposite ways. A 1 mg vial in 1 mL puts a 20 mcg amount at two units, where a half-unit misreading is a quarter of the amount. A 0.1 mg vial in 2 mL puts 100 mcg at 200 units, which is two full syringes. The rows in the middle are where a draw is both readable and holdable, and that is the only thing the water volume decides — it never changes how much peptide is in the vial, a point the reconstitution hub makes for every compound.
What is actually in the vial
Two published analyses exist, and neither is reassuring about identity. The Cologne doping-control laboratory took one injection vial confiscated from the black market and characterised its contents by mass spectrometry as Long-R3-IGF-I with a His6 tag attached to the C-terminus through a Leu-Glu linker. A histidine tag is a production convenience: it lets a protein be pulled out of a mixture in one step, and it is normally removed afterwards. Its presence means the material was made for biochemistry rather than for administration, and the authors wrote that the effects of the tagged form in humans have not been elucidated.
The French laboratory's 2021 method paper adds the second finding: the black-market products it worked with contained abundant oxidised forms of the peptide, in quantities large enough that the detection method had to monitor the mono-oxidised form as well as the native one. Peptifact's IGF-1 LR3 dosage page covers the provenance of the circulating figures in more detail; the mechanism and the evidence file are in Medibact's IGF-1 LR3 guide.
What the figures omit
The animal figures carry a species, a life stage — fetal or neonatal in three of the five studies — a continuous intravenous route in most of them, and a duration of a week. They do not carry an adult, a subcutaneous route at an adult's body size, a pharmacokinetic profile in people, any safety data in people, or any dose-finding work at all. The label figures carry a different molecule, a paediatric deficiency population and a manufactured solution of known concentration. The circulating figures carry nothing: no study, no label, no population and no source. That is not a gap between a strong and a weak number; it is the difference between a number and a habit.
What this page does not do
It does not state an amount of IGF-1 LR3 to use, a frequency, a cycle length or a route. It reports the published animal rates with their species and durations, reports the approved label of a related molecule, converts both into concentrations and U-100 syringe units at each vial size, and says which source each figure came from. Decisions about administering anything to a person belong with a clinician.
Sources and dates
Opened 2026-09-20: PubMed through the NCBI E-utilities for the analogue's name forms in title or abstract (78 records; 25 with the human tag) with the abstracts of PMIDs 39679943, 33938236, 37114757, 9252489, 10370861, 33587816 and 20675162 read; the ClinicalTrials.gov v2 API for IGF-1 LR3, Long R3 IGF-1 and mecasermin as interventions (zero, zero and 37 records); the DailyMed SPL search API for mecasermin (three records) and the full INCRELEX label from Eton Pharmaceuticals, published 2026-05-20, sections 2.1, 2.2 and 3; PubChem name searches for the analogue (no compound record — expected for a protein of this size, and not evidence either way); MedlinePlus, "Giving an insulin injection" (reviewed 2024-07-21). The circulating vial figures are as recorded in this site's dosage chart on 2026-09-18. Corrections go to the contact page.