documented protocols
IGF-1 LR3: what is documented about dosing
The animal studies state what they infused into sheep and cattle. That is the entire documented record and it does not convert into an amount for a person.
- Primary sources Registry records and papers are read at the source, not through summaries. Read the methodology
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What follows is what published studies delivered to research animals, reported as that and nothing else.
Not medical advice
This page reports what has been documented about a compound. It is not medical advice, not a diagnosis, not a dosing protocol, and not a recommendation to obtain or use anything described here. Talk to a licensed clinician about anything concerning your health. Read the full disclaimer.
Reviewed against editorial standards Updated
What this page reports, and what it does not
We report what has been documented. We do not prescribe what should be done.
Nothing here is a dosing recommendation. Statements about dosing reflect community and research reports only.
No trial established an amount of IGF-1 LR3 for a person. Most of the rows below record what a published study gave to its animals or its cells, in the model that study built, with the species and the route named on the line. One row records that other figures circulate in community write-ups, and that this site does not republish them. Nothing here is a protocol, nothing here is scaled for a person, and this site publishes no preparation steps, no administration technique and no equipment. The reasoning is in the editorial policy.
Commonly cited protocols (extrapolated, not validated)
| Study | What was given | Frequency | Duration | Notes |
|---|---|---|---|---|
| Fetal sheep programme | An infusion rate stated per kilogram in the source papers | Continuous infusion | One week in the studies reporting insulin effects | Read from abstracts. The full texts were not read, and the figure should be confirmed before it is relied on |
| Beef heifers, 1999 | An intravenous infusion described in the source paper | Continuous infusion | Eight hours | Animals under restricted feeding. Amino acids and glucose both fell markedly |
| Any human use | Nothing documented | Nothing documented | Nothing documented | No registered or published human study of this analog exists |
Commonly cited protocols (extrapolated, not validated) circulate for this compound in microgram amounts by injection. They did not come from a study of people, because no study of people exists.
The animal figures cannot be scaled across. They were continuous infusions into a research preparation, one of them a fetus in utero, at rates chosen to answer a question about that preparation. There is no human route, no human exposure measurement and no pharmacokinetic bridge, so there is nothing to scale and nothing to scale it with.
Nothing here is a dosing recommendation. Statements about dosing reflect community and research reports only.
Our takeThere is no documented amount for a person and nothing published from which one could be derived.,Talk to a licensed clinician about anything concerning your health.
Main routes people compare
Injection
The route the compound is sold for. No published study has measured what this analog does in a person by this route or any other.
The infusion routes used in animals
The published work used continuous infusions into sheep and cattle. Those are laboratory preparations chosen to answer a physiological question, and they carry no implication for a person.
What is said about cycle length and timing
The animal studies ran for one week and for eight hours respectively. No cycle length for a person appears anywhere in the published record, because no study of a person has been run.
Talk to a licensed clinician about anything concerning your health.
What has been measured about safety
A reader weighing what other people report giving usually wants the other half of the record next. What has been measured about IGF-1 LR3, and what has never been studied reports what has actually been measured, in what system and over what period, and the questions no published study has put.
Frequently asked questions
Is there an established dose for IGF-1 LR3?
No. No human study of this analog has been published or registered, so no amount has been established and there is no measurement from which one could be derived.
Can the animal infusion rates be scaled to a person?
No. They were continuous infusions into sheep and cattle, one of them a fetus, at rates chosen for those experiments. There is no human route, no exposure measurement and no pharmacokinetic bridge to scale across.
Do the mecasermin dosing figures apply?
No. Mecasermin is the unmodified protein and this analog was engineered specifically to behave differently from it, which is the entire point of the modification.
References
- White A, Stremming J, Wesolowski SR, Al-Juboori SI, Dobrinskikh E, Limesand SW, Brown LD, Rozance PJ. IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep. Am J Physiol Endocrinol Metab. 2025. PMID 39679943 DOI 10.1152/ajpendo.00259.2024 Describes the analog as having low affinity for IGF-binding proteins and high affinity for the IGF-1 receptor. Read as an abstract; the full text was not read.
- White A, Stremming J, Boehmer BH, Chang EI, Jonker SS, Wesolowski SR, Brown LD, Rozance PJ. Reduced glucose-stimulated insulin secretion following a 1-wk IGF-1 infusion in late gestation fetal sheep is due to an intrinsic islet defect. Am J Physiol Endocrinol Metab. 2021. PMID 33938236 DOI 10.1152/ajpendo.00623.2020
- White A, Stremming J, Brown LD, Rozance PJ. Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets. J Dev Orig Health Dis. 2023. PMID 37114757 DOI 10.1017/S2040174423000090
- Hill RA, Hunter RA, Lindsay DB, Owens PC. Action of long(R3)-insulin-like growth factor-1 on protein metabolism in beef heifers. Domest Anim Endocrinol. 1999. PMID 10370861 DOI 10.1016/s0739-7240(99)00015-6 Reports a tendency for whole-body and skeletal muscle protein to be conserved, alongside markedly reduced plasma concentrations of all amino acids measured and of glucose.
- Dominikowski A, Rękoś Z, Olejarz M, Szczepanek-Parulska E, Domin R, RuchaŁa M. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol (Lausanne). 2026. PMID 42395176 DOI 10.3389/fendo.2026.1822475 Names IGF-1 Long R3 among agents marketed as research compounds. Read in full on 23 August 2026.
- ClinicalTrials.gov. Registry sweep for mecasermin, Increlex, mecasermin rinfabate, iPlex, rhIGF-1, IGF-1 LR3 and Long R3 IGF-1, run through the v2 API on 23 August 2026 and filtered to records whose interventions name one of those drugs. Twenty-nine records survive the filter and none names LR3 or Long R3. An unfiltered query returns 135, because IGF-1 is a widely measured biomarker. ClinicalTrials.gov. 2026. ClinicalTrials.gov
- World Anti-Doping Agency. The 2026 Prohibited List. Section S2.3, Growth Factors and Growth Factor Modulators, carries the entry: Insulin-like growth factor 1 (IGF-1, mecasermin) and its analogues. The S2 class heading states that the class is prohibited at all times, in and out of competition, and that all substances in it are non-Specified. Read in full on 23 August 2026. World Anti-Doping Agency. 2026. WADA 2026 Prohibited List
- US Food and Drug Administration. INCRELEX (mecasermin) injection prescribing information, BLA021839, Ipsen Biopharmaceuticals, Inc. Read via the openFDA drug label API on 23 August 2026. Cited here for the approved population of the unmodified protein, which is a different molecule from the analog this page covers. openFDA drug label. 2026. Increlex label
- Stremming J, Heard S, White A, Chang EI, Shaw SC, Wesolowski SR, Jonker SS, Rozance PJ, Brown LD. IGF-1 infusion to fetal sheep increases organ growth but not by stimulating nutrient transfer to the fetus. Am J Physiol Endocrinol Metab. 2021. PMID 33427051 Part of the same fetal sheep programme, cited for the programme's design rather than for a finding about the analog specifically.
- Jonker SS, Giraud GD, Chang EI, Elman MR, Louey S. Coronary vascular growth matches IGF-1-stimulated cardiac growth in fetal sheep. FASEB J. 2020. PMID 32573852 Part of the same fetal sheep programme.
- Stremming J, White A, Donthi A, Batt DG, Hetrick B, Chang EI, Wesolowski SR, Seefeldt MB, McCurdy CE, Rozance PJ, Brown LD. Sheep recombinant IGF-1 promotes organ-specific growth in fetal sheep. Front Physiol. 2022. PMID 36091374 Cited to show what the unmodified protein does in the same preparation the analog was tested in.
- Lu Z, Liu N, Huang H, Wang Y, Tu T, Qin X, Wang X, Zhang J, Su X, Tian J, Bai Y, Luo H, Yao B, Zhang H. Recombinant expression of IGF-1 and LR3 IGF-1 fused with xylanase in Pichia pastoris. Appl Microbiol Biotechnol. 2023. PMID 37261455 Cited for how the analog is produced, not for any biological finding.