Question 1

Is there a dosage for IGF-1 LR3?

Accepted Answer

No published human study has administered IGF-1 LR3 to a person, so there is no amount, route or schedule to report. That is the direct answer to the most-searched version of this question. The remainder of this page is what sits behind it. A 2026 review of performance-enhancing peptides lists IGF-1 Long R3 (IGF-1 LR3) among the IGF-1 analogues sold as research compounds, alongside pegylated mechano growth factor. The same review sorts the entire category into evidence tiers from regulatory-grade randomized trial data to a complete absence of human studies. So a search for an LR3 amount is a search for something no study among the research behind this page has published. That is a gap in the documented record rather than a secret anybody is keeping, and the gap is itself the finding. What exists instead is one approved schedule written for children, plus two animal experiments.

Question 2

What is in an IGF-1 LR3 dosage protocol?

Accepted Answer

Protocols circulate. They simply do not come from trials, and the 2026 review exists because clinicians keep meeting patients who followed one. That review sets peer-reviewed clinical evidence against the self-administration protocols found online, and lists the dosing patterns they report. What it never does is back one. It names the uncertainty around product composition, dose and stacking in unregulated supply, and says its aim is to help clinicians without legitimising off-label peptide regimens. We take the same line, for the same reason. A number passed around a forum came from somewhere, but nothing we could find stands behind it, and printing it next to a citation would lend it an authority it has not earned. That is an origin rather than evidence.

Question 3

What did the published IGF-1 LR3 experiments actually give?

Accepted Answer

Two published experiments administered IGF-1 LR3 to something living, and neither involved a person. The more detailed is a 2020 study in sheep. Near-term fetal sheep underwent surgical instrumentation and were studied from 127 to 134 d gestation (term = 147 d), receiving either IGF-1 LR3 or vehicle. That is a seven-day window in an unborn animal with a catheter already in place, measured against a dummy infusion. A 2003 experiment in the same species reports that in vivo administration of Long R3 IGF-1 (LR3 IGF-1) did not stimulate cardiomyocyte hypertrophy, meaning heart cells growing larger. Read what that design supplies. A week-long infusion into a fetal lamb is a genuine protocol with a genuine control, and it is not a weekly amount for an adult. No study among the research behind this page has published the step between the two.

Question 4

What schedule has a regulator approved?

Accepted Answer

One schedule carries a regulator's name, and it belongs to mecasermin, the recombinant human form of the hormone. A 2008 review describes it directly: subcutaneous mecasermin, given twice daily and scaled to body weight, in children with growth failure and severe IGF-I deficiency. A second preparation runs on a different clock. Mecasermin rinfabate pairs the hormone with its binding protein, and a 2008 review of it states that it is administered as a once-daily subcutaneous injection. Another review records that the same complex was cleared by the U.S. Food and Drug Administration for severe primary IGF deficiency. Each schedule belongs to the indication it was approved for. Neither was written for an adult, and neither was written for material bought outside a pharmacy.

Question 5

How was it given, and when?

Accepted Answer

Under the skin, by injection, and timed around food. A 2009 review names low blood sugar as the most frequent side effect and notes that it is readily controlled by administration with meals, which makes mealtimes part of the schedule rather than an afterthought. One published case went further than injections. In a patient with a severe insulin-resistance syndrome, initial rhIGF-I application via BID (twice daily) injection was unsatisfactory, but continuous subcutaneous rhIGF-I infusion via an insulin pump improved weight development and diabetes control. The authors suggest continuous application via pump might be advantageous compared to single injections. That is one patient in one report, and he died at 22 months of age during the course of a respiratory infection. It records that a pump has been tried rather than that a pump works.

Question 6

Why do the published schedules differ?

Accepted Answer

Because the two preparations behave differently once they are in the blood, and that difference is the entire reason the second one was built. A 2007 review explains that the serum half-life of unbound rhIGF-I is shorter when administered to patients with growth hormone insensitivity syndrome, who carry low concentrations of its binding proteins, than in healthy volunteers. Mecasermin rinfabate prolongs the half-life of rhIGF. A 2006 review describes it as an equimolar mixture of IGF-I and its binding protein IGFBP-3, developed to prolong the half-life. A dose-ranging study put a figure on the consequence. A single dose of mecasermin rinfabate delivered the same amount of IGF-1 as two daily injections of unbound IGF-1. So frequency here tracks the preparation rather than the person, which is why one published schedule cannot be read across to another one.

Question 7

How long did people stay on it?

Accepted Answer

Years rather than weeks, and that is one of the firmer facts in this record. In the trial supporting the US approval the mean duration of therapy was 4.4 years, with a range of 0.04-12.5 years, and mean growth velocities remained above baseline for up to 8 years. A smaller group was followed considerably longer: after 6.5-7.5 years of mecasermin therapy, the mean increase in the height standard deviation score was +1.4, a score describing height against others of the same age. Outside growth failure the exposures contract sharply. A Rett syndrome investigation ran a 20-weeks phase I open label trial of mecasermin (recombinant human IGF-1) in children. Continuous administration across years is what the approved indication demands, because its outcome is a child's eventual height. None of that duration transfers to an adult holding a research compound for an unrelated reason.

Question 8

What about an IGF-1 dosage for bodybuilding?

Accepted Answer

There is no approved amount for muscle and no trial amount either. No study among the research behind this page has given IGF-1 or IGF-1 LR3 to a healthy adult and measured muscle size or strength. The clinical literature is blunt about the ceiling. A 2009 review concludes it is unlikely that mecasermin will be useful beyond the orphan indications of severe insulin resistance and GH insensitivity. A 2015 review adds that few young/adult patients will benefit from treatment with the rIGF-I, mecasermin, given the number of adverse effects found. Both sentences describe supervised use in diagnosed patients, which is the only setting anybody has studied. So the question does have an answer, and the answer is not a number. Every amount on record was written for children who cannot make the hormone, and the adult physique question has not been asked in a published trial.

Question 9

What does a 1 mg vial tell you?

Accepted Answer

It tells you how much powder is inside the glass, and nothing beyond that. A vial size is a packaging fact rather than a protocol, and no study among the research behind this page used a 1 mg vial as its unit of anything. The arithmetic from there is fixed, and worth knowing because it is where most unit errors happen. Milligrams multiplied by 1,000 give micrograms. Micrograms divided by the millilitres of water added give the strength per millilitre. A U-100 syringe is marked in insulin units, where 100 units is one millilitre, so a single unit is 0.01 mL. Our reconstitution calculator runs that arithmetic and deliberately proposes no target. What the arithmetic cannot supply is the figure you would multiply. The 2026 review also names the uncertainty surrounding product composition, which is the second reason a label on a vial settles very little.

Question 10

Is how much IGF-1 the same question as what my IGF-1 level is?

Accepted Answer

No. One is a measurement and the other is an administration, and no source among the research behind this page converts between them. A laboratory result describes what somebody's own body is producing. A 2015 review makes IGF-I measurement central to diagnosing and treating conditions such as acromegaly and growth hormone deficiency, the use the assay was developed for. The threshold behind the one approved indication is expressed as a score rather than an amount: severe primary IGF-1 deficiency means a basal IGF-1 standard deviation score (SDS) less than or equal to -3. So a low result arrives with no amount attached, and an amount arrives with no target concentration attached. Where a reading sits, what moves it and what an elevated one means belong on the IGF-1 hub. This page covers what has been administered.

Question 11

How much does an IGF-1 injection cost?

Accepted Answer

One published price exists, and it belongs to the approved medicine. A Canadian reimbursement review states that treatment with Increlex is expected to cost approximately $183,416 per patient per year, assuming an average patient weight of 14.1 kg, and adds that the cost of Increlex will vary by each patient's weight. Read the weight in that sentence, because it belongs to a small child. The administered amount is scaled to body weight, so the annual expenditure scales with it. That figure therefore describes a paediatric course rather than anything an adult would encounter. The same review judged the price unjustified, requiring at least a 92% price reduction, and projected an increase of $35,982,122 over 3 years to Canadian public plans. None of that describes what anything costs outside a pharmacy, and no source among the research behind this page does.

Question 12

Is there a cycle length, or a break?

Accepted Answer

Nothing published describes cycling IGF-1 in either form, and the approved use is the opposite of a cycle. In one paediatric group, subjects with IGF-1 deficiency syndrome were monitored for 4-5 years of rhIGF-1 treatment. That is years of supervised use, counted in years rather than in blocks and breaks. The one documented interruption came from supply rather than from design. A 2014 review was written partly to explain how to reinitiate therapy, given the recent drug shortage with mecasermin. A 2025 systematic review of mecasermin in Rett syndrome closes by calling for larger, rigorously designed trials to refine treatment regimens. When specialists say the regimens still need refining in the one condition where this hormone is seriously studied, a cycle length for a research compound is not something anybody has established.

Study	Time on mecasermin	What was recorded
Trial supporting the US approval	Mean 4.4 years, range 0.04-12.5 years	Growth velocity above baseline for up to 8 years
Longer follow-up group	6.5-7.5 years	Mean height score up by +1.4
Rett syndrome phase I trial	20 weeks	Open-label trial in children

IGF-1 protocols in the published literature