IGF-1 LR3 (Long R3 IGF-1): What Users Report
Long-chain analogue of insulin-like growth factor 1 with extended half-life. Binds IGF-1 receptors to promote muscle protein synthesis and cellular growth.
Also known as:
often mentioned with:
Anonymous user report. Not medical advice. Peptides discussed are not FDA-approved for the uses described. Editorial process →
What is IGF-1 LR3?
IGF-1 LR3 (Long R3 IGF-1) is a lab-made version of insulin-like growth factor 1. The long-R3 change is meant to extend how long it stays active compared with the hormone the body makes. It is not an approved drug.
On this site it shows up in muscle-building and recovery stories. The description above is the compound. The sections below are only what the published confessions say, and there are two of them.
What the research says
IGF-1 LR3 has been used mainly as a cell-culture reagent; there are no published human trials of it as a supplement or performance drug. What is known about IGF-1 in people comes from mecasermin, an approved IGF-1 for a rare growth disorder, whose label lists low blood sugar as a common side effect. IGF-1 signalling also promotes cell growth, which is why long-term cancer-risk questions are raised in the research literature. IGF-1 and its analogues are on the WADA prohibited list. Last reviewed: October 2026.
What does IGF-1 LR3 do? What people report
These are personal accounts, not evidence. #401 says a knee that had hurt for years stopped hurting after two weeks of NAD+ and IGF-1 LR3 together. The writer is explicit that both were in the mix, and that the change was a surprise.
#210 says they have been running IGF-1 LR3 "at numbers that would scare most of you" for twelve years. It does not describe an effect, a benefit, or a side effect.
IGF-1 LR3 side effects reported by users
Neither published confession describes a side effect. Low blood sugar is the risk that comes up most often in community discussion of IGF-1 LR3 elsewhere; it is not something these two reports mention. If you have symptoms, talk to a clinician.
Is IGF-1 LR3 safe?
IGF-1 LR3 is not approved for human use, and long-term human safety data are limited. Two anonymous stories cannot answer a safety question in either direction. This page does not claim it is safe, and it does not claim it is not.
IGF-1 LR3 dosage: what people report running
The two confessions do not state a dose. #210 refers to amounts without giving a number. There is no reported pattern on this page to summarise.
This is not a dosing recommendation.
IGF-1 LR3 benefits users describe
The only benefit anyone describes here is #401's knee, and that account also names NAD+. #210 describes no benefit. With two reports, that is the whole list.
IGF-1 LR3 vs HGH and common stacks
These two confessions do not compare IGF-1 LR3 with HGH. For the comparison topic, see IGF-1 LR3 vs HGH. Stack talk on the site lives in Best Peptide Stacks.
Related GH peptides people look up next to this one: MK-677, CJC-1295, and sermorelin.
Anonymous IGF-1 LR3 reports
Two reports is a thin file. If you have used IGF-1 LR3, submit what actually happened.
Submit yoursCommunity Q&A
- Can IGF-1 LR3 cause low blood sugar?
- Yes, it is a plausible risk. IGF-1 has insulin-like effects, and low blood sugar (hypoglycaemia) is a known side effect of the approved IGF-1 drug mecasermin. Shakiness, sweating or confusion need prompt attention.
- What is IGF-1 LR3?
- IGF-1 LR3 (Long R3 IGF-1) is a lab-made version of insulin-like growth factor 1 with a longer activity window than the hormone the body makes. It is not an approved drug. This page has two anonymous confessions about it.
- What does IGF-1 LR3 do, according to users?
- According to the two published reports: one person says a long-standing knee pain stopped after two weeks of NAD+ and IGF-1 LR3 together (#401). The other says they have run it for twelve years and does not describe an effect (#210). These are personal accounts, not evidence.
- What side effects do people report with IGF-1 LR3?
- The two confessions on this page do not describe a side effect. Low blood sugar is the risk most often raised in community discussion of IGF-1 LR3; it is not mentioned in these reports. If you have symptoms, talk to a clinician.
- Is IGF-1 LR3 safe?
- It is not approved for human use, and long-term human safety data are limited. Two stories cannot establish safety either way. This page makes no safety claim.
- What doses do people report using?
- They don't, in the reports published here. Neither confession states a number. That is not a dosing recommendation — there is no pattern on this page to recommend.
- How is IGF-1 LR3 different from HGH?
- The two IGF-1 LR3 confessions do not make that comparison. The site's separate topic page, IGF-1 LR3 vs HGH, is where that discussion is collected.
- Is IGF-1 LR3 a peptide?
- Yes. It is a synthetic peptide analogue of insulin-like growth factor 1. Being a peptide is a description of the molecule, not a statement about safety or effect.
- What are the claimed benefits of IGF-1 LR3?
- Online claims centre on muscle growth and recovery. This archive cannot confirm them: of the two published confessions, one describes knee pain easing on a stack that also included NAD+ (#401), and the other describes no specific effect (#210). A claimed benefit is not a reported result.
- Is IGF-1 LR3 legal in Canada or the US?
- It is not an approved drug in either country. In Canada, Health Canada says 'research use only' labelling does not make an unauthorized peptide legal to sell for human use. It is also prohibited in sport under the WADA list. This is not legal advice.
- IGF-1 LR3 vs IGF-1: what is the difference?
- IGF-1 is the hormone the body makes. IGF-1 LR3 is a modified synthetic version with an extra 13-amino-acid extension and one amino-acid substitution, designed to bind less to the proteins that normally carry IGF-1, so it stays active longer.
- Does IGF-1 LR3 increase testosterone?
- There is no evidence that IGF-1 LR3 raises testosterone in people.
- Is IGF-1 LR3 better than HGH?
- There are no human studies comparing them. HGH is an approved prescription drug for specific conditions; IGF-1 LR3 is an unapproved research compound with no human trials.
Anonymous first-hand reports plus sourced context — educational only, not medical advice. Editorial policy & corrections.