IGF-1 LR3 Reconstitution Calculator
IGF-1 LR3 has never been approved for human use in any jurisdiction and has never entered human clinical trials. It is sold as a laboratory research reagent, and it is a potent growth factor: hypoglycaemia is the dose-limiting toxicity of this class, because IGF-1 has insulin-like activity at the insulin receptor, and receptor activation is also mitogenic. No human dosing study of this analogue has ever been published, so there is no established dose, no established frequency and no monitoring schedule, and this page states none. Of the 45 abstracts gathered for it, exactly one studies Long R3 IGF-I itself, and that one is an animal study. It must not be confused with mecasermin, an approved recombinant human IGF-1 that is a different molecule with its own label. It ships as a lyophilised powder, and the calculator below converts a vial size and a mixing volume into mg/ml and syringe units, which is arithmetic about a vial rather than a dose.
Curated by Dosavy from published literature and regulator labels. Published 11 September 2026, last reviewed 11 September 2026. No clinician reviews this page.
No established human dose
No human trial has established a dose for IGF-1 LR3. There is no evidence-based dose to give, and this page does not give one.
The calculator below converts a vial size and a mixing volume into a concentration. That is arithmetic about the vial, not a recommendation about what to inject.
Enter a target dose above to see the draw.
What the evidence says
No human dosing trial of IGF-1 LR3 exists, and the literature that looks like it might be about IGF-1 LR3 is almost entirely about something else. Of the 45 abstracts fetched for this compound, exactly one studies Long R(3)IGF-I itself, a subcutaneous study in adolescent female rhesus monkeys (PMID 10753591), an animal study, which under the sourcing standard can support mechanism only and can never back a human dosing range. The remainder describe mecasermin / rhIGF-1 (Increlex, iPLEX) in severe primary IGF-1 deficiency, Laron syndrome, Rett syndrome and Duchenne muscular dystrophy, or measure endogenous IGF-1 as a biomarker. Those are a different molecule and, in most cases, a paediatric deficiency population, neither the molecule nor the population matches, so their dosing does not transfer. The only human-facing document in the corpus that names IGF-1 LR3 directly is a 2026 narrative review of self-administered performance peptides (PMID 42395176), which places it in the tier characterised by a complete absence of human studies and describes commonly circulated protocols without endorsing a dose.
IGF-1 LR3 at a glance
- Category
- Hormone
- Half-life
- Not established
- Routes
- Subcutaneous
- Regulatory status
- Research use only
- Also sold as
- Long R3 IGF-1, LR3 IGF-1, Long R(3) IGF-I, IGF-1 Long R3, igf 1 lr3
Mechanism
An engineered analogue of human insulin-like growth factor 1 carrying an arginine substitution at position 3 and a 13-residue N-terminal extension. Those changes sharply reduce its affinity for the IGF binding proteins that normally sequester circulating IGF-1, so a larger fraction of what is injected stays free and available to activate the IGF-1 receptor. The mechanistic consequence was shown directly in adolescent rhesus monkeys: native IGF-I raised serum IGFBP-3 after subcutaneous injection whereas Long R(3)IGF-I did not, either acutely or on continuous infusion (PMID 10753591). Downstream IGF-1 receptor signalling drives protein synthesis, cell growth and proliferation, and has insulin-like effects on glucose uptake. This mechanism description rests on animal and in-vitro work; it has never been characterised in humans for this analogue.
Reconstitution
Supplied as a lyophilised powder requiring reconstitution before injection. No validated diluent, concentration or in-use stability period exists because no approved product exists.
Storage
Sold as a lyophilised powder by suppliers who publish no stability data. No approved product exists, so there is no manufacturer or regulatory storage specification.
Frequency in practice
No established regimen. No human dosing study of IGF-1 LR3 has ever been published, so there is no evidence-based frequency to state.
Regulatory
Never approved for human use in any jurisdiction and never entered human clinical trials. It is sold as a laboratory research reagent. IGF-1 LR3 must not be confused with mecasermin (Increlex), an FDA-approved recombinant human IGF-1 for severe primary IGF-1 deficiency: mecasermin is native IGF-1 with a label, a dose and a monitoring regimen, while IGF-1 LR3 is a modified analogue engineered specifically to escape the binding proteins that constrain native IGF-1. IGF-1 and its analogues are prohibited in competitive sport.
What to know before anything else
Not approved for human use anywhere, and no human dosing study of IGF-1 LR3 has ever been published. Whatever protocol a supplier or forum supplies, no one has measured what it does in a person.
DO NOT TRANSFER MECASERMIN (INCRELEX) DOSING. Mecasermin is native rhIGF-1; IGF-1 LR3 is deliberately engineered to evade IGF binding proteins, so the same milligram amount produces a substantially larger free-IGF-1 exposure. Milligram-for-milligram equivalence between the two is not just unproven: the analogue was designed to break it.
Hypoglycaemia is the dose-limiting toxicity of the IGF-1 class. IGF-1 has insulin-like activity at the insulin receptor, and registry data on patients treated with approved rhIGF-1 show hypoglycaemia is a frequent adverse event (PMID 37579214). Reduced binding-protein sequestration means an analogue like LR3 raises rather than lowers that risk.
IGF-1 receptor activation is mitogenic. A 2026 review of GH-IGF-1-axis performance peptides, which covers IGF-1 LR3 by name, flags biologically plausible but unproven mitogenic concerns alongside dysglycaemia and fluid retention (PMID 42395176). Anyone with an active or prior malignancy should treat this as a hard contraindication.
Animal work on this analogue is dosed in mcg/kg or mg/kg of body weight. Converting an animal dose into a human dose by body-weight or body-surface-area scaling produces a number that looks rigorous and is not evidence. There is no valid conversion.
The compound suppresses endogenous growth hormone through negative feedback: in the monkey study both IGF-I and Long R(3)IGF-I acutely suppressed serum GH.
Reviewed interactions
These are the pairs Dosavy holds reviewed, cited data on. A combination that is not listed here has not been assessed, which is not the same as being safe.
- Cautionwith MK-677 (Ibutamoren)
MK-677 raises IGF-1 by amplifying your own growth hormone; IGF-1 LR3 supplies IGF-1 directly and, because it evades the binding proteins that normally sequester it, a larger fraction stays free and active. Stacking them raises free IGF-1 from two directions at once, and hypoglycaemia is the characteristic adverse event of IGF-1 therapy.[1]
IGF-1 LR3's reduced affinity for IGF binding proteins keeps more of the injected peptide bioavailable; MK-677 adds endogenously generated IGF-1 on top. IGF-1 has insulin-like activity at the insulin receptor at sufficient concentrations.
One dangerous interaction with a prescription-only compound not listed on this site is recorded in the app.
IGF-1 LR3 questions
Is there a published human dose for IGF-1 LR3?
No. No human dosing study of IGF-1 LR3 has ever been published, and the literature that looks like it might be about this compound is almost entirely about something else. Of 45 abstracts gathered, exactly one studies Long R3 IGF-I itself, a subcutaneous study in adolescent female rhesus monkeys. The rest describe recombinant human IGF-1 in severe primary IGF-1 deficiency, Laron syndrome, Rett syndrome and Duchenne muscular dystrophy, or measure IGF-1 as a biomarker. Different molecule, and in most cases a paediatric deficiency population, so neither the drug nor the people match.
What does the LR3 modification change, and why does it matter?
It is an engineered analogue of human IGF-1 carrying an arginine substitution at position 3 and a 13-residue extension at the N-terminus. Those two changes sharply reduce its affinity for the IGF binding proteins that normally sequester circulating IGF-1, so a larger fraction of what is injected stays free and available at the IGF-1 receptor. The consequence was shown directly in the monkey study: native IGF-I raised serum IGFBP-3 after subcutaneous injection whereas the LR3 analogue did not, acutely or on continuous infusion. Both suppressed the animals' own growth hormone. Everything known about this mechanism comes from animal and laboratory work; none of it has been characterised in a person.
Can mecasermin or Increlex dosing be used for IGF-1 LR3?
No, and this is the single most dangerous assumption made about this compound. Mecasermin is native recombinant human IGF-1 with an approved label, a dose and a monitoring regimen. IGF-1 LR3 was deliberately engineered to evade the binding proteins that constrain native IGF-1, so the same amount by mass produces a substantially larger free-IGF-1 exposure. Equivalence between the two is not merely unproven: breaking it is what the modification was for.
Why is hypoglycaemia the main risk with IGF-1 LR3?
Because IGF-1 acts at the insulin receptor as well as its own. Registry data on patients treated with approved recombinant IGF-1 under medical supervision show hypoglycaemia as a frequent adverse event, and it is why supervised IGF-1 dosing is tied to food intake and blood glucose monitoring. Neither of those is built into how this compound is sold. Reduced sequestration by the binding proteins means an analogue like this one raises that risk rather than lowering it, and stacking it with anything that independently raises IGF-1 pushes from two directions at once.
Can an animal dose of IGF-1 LR3 be scaled to a person?
There is no valid conversion. The animal work on this analogue is dosed per kilogram of body weight, and converting an animal figure into a human amount by body weight or body surface area produces a number that looks rigorous and is not evidence. It has never been validated for this analogue, in either direction. The figure that circulates online has no published human study behind it, which is why none appears on this page.
Is IGF-1 LR3 safe for anyone with a history of cancer?
Treat it as a hard contraindication. IGF-1 receptor activation is mitogenic, meaning it drives cell growth and proliferation, and a 2026 review of growth hormone and IGF-1 axis performance peptides that covers IGF-1 LR3 by name flags biologically plausible but unproven mitogenic concerns alongside dysglycaemia and fluid retention. Unproven there means nobody has run the study, not that the concern has been tested and cleared. Anyone with an active or prior malignancy is the group with the least reason to accept that particular unknown.
How should an IGF-1 LR3 vial be stored and reconstituted?
There is no answer that carries any weight. It is supplied as a lyophilised powder by suppliers who publish no stability data, and because no approved product exists there is no manufacturer or regulatory storage specification, no validated diluent, no validated concentration and no in-use stability period. Every storage claim printed on such a vial, including its expiry date, is untested convention. The mass printed on the vial is the seller's claim as well, so any concentration calculated from it inherits that uncertainty.
Every number above, and where it came from
One source, numbered where it is used. Each one links to the paper or the label itself, not to a summary of it.
- [1]Frequency and Predictive Factors of Hypoglycemia in Patients Treated With rhIGF-1: Data From the Eu-IGFD Registry
The Journal of Clinical Endocrinology and Metabolism · 2023 · Registry study
The rest of the math
- Reconstitution calculatorThe full version of the tool above, with syringe barrel sizes and IU conversion.
- Vial longevityHow many doses a vial holds and the date it runs out.
- Cost per doseVial price against doses drawn, so two vial sizes can be compared honestly.
- Half-life and decayFirst-order clearance, time to steady state, and what remains at a given hour.
Same class as IGF-1 LR3
You worked out the draw. Now log this dose.
A calculator answers once and forgets. Dosavy keeps the concentration you mixed, the doses you actually took, and a reminder for the next one, with the same evidence labels you see on this page.