Metabolic Category
THE MUSCLE MAXIMIZER
Long R3 Insulin-like Growth Factor-1; LR3 IGF-1
IGF-LR3 is a modified version of IGF-1 with a much longer half-life. The modifications make it more potent and longer-lasting than natural IGF-1. It activates muscle satellite cells, promotes protein synthesis, and has powerful anabolic effects, which makes it popular among bodybuilders and those seeking muscle growth.
Dose and schedule recommendations shown below come from The Peptide App Clinical Team. Research links are provided so readers can inspect the supporting evidence directly. Review the sources.
No. This profile records IGF-LR3 as not FDA approved and for research use only.
Review the regulatory and source details on this page for the current context.
Dose: 20-50 mcg daily.
Schedule: daily. Cycle: 4-6 weeks on, 4 weeks off. This is clinical-team guidance for reference and does not replace individualized instructions from a licensed clinician.
This guide links to 1 curated or current research sources.
Open the research section to inspect the source titles, publication details, study types, and available abstracts directly.
Review the IGF-LR3 research sourcesReported side effects of IGF-LR3 include Hypoglycemia, Injection site irritation, Jaw/hand numbness, and Joint pain.
They are reported or occasional reactions, not a prediction of what any one person will experience.
IGF-LR3 has an editorial safety grade of C (Moderate Safety).
Potent anabolic with potential for hypoglycemia and other effects. Safety depends on dose, sourcing, health history and medical supervision, so this page does not call it safe for personal use.
Strongly activates IGF-1 receptors for growth signaling
Stimulates protein synthesis and satellite cell activation
Modified structure resists binding proteins, lasting much longer
The Long R3 form of IGF-1 has two defining structural changes: a 13-amino-acid extension at the beginning of the chain and an arginine substitution at position 3 of the original IGF-1 sequence. Researchers have used this modified molecule to investigate how IGF proteins fold and form disulfide bonds. The name describes those structural changes, not a treatment schedule.
[Long-[Arg3]IGF-I folding study, 1999](https://pubmed.ncbi.nlm.nih.gov/9951525/)
Bodybuilders seeking muscle growth · Athletes wanting enhanced recovery · Those with muscle-wasting conditions · People wanting fat loss with muscle preservation
In-stock prices from 1 vendor, checked Oct 14, 2026.
Market evidence
We found certificates from some of the IGF-LR3 vendors we track. Based on the certificates our crawler found; vendors may publish more than we index. Research on this page describes the molecule. Vendor certificates concern particular market samples or batches; they do not change the research evidence or establish clinical safety, sterility, or suitability for use.
Certificate assessment
3 evaluated certificates
3 graded · 0 not graded · 0 in the A range.
Each result belongs to the named vendor’s certificate. Grades assess the document and its reported tests, not the vendor’s whole catalog or the safety of a product.
Automated checks can make mistakes. Open “Why this result?” for the reason and any review notice, and check the linked COA’s lot against your product. How grading works
3 evaluated records
Document grade
C10: No endotoxin (bacterial toxin) test is reported, and an injectable needs one, so the grade stops at D.
Document check: flag.
Lab record: not confirmed.
Graded Oct 14, 2026 · Grader 0.4.9 · Policy 2026-10-07.2
IGF26-01-001 vial 2
Document grade
B8: Key details are missing from the certificate: lot number and analysis or report date.
Document check: flag.
Lab record: not confirmed.
Graded Oct 14, 2026 · Grader 0.4.9 · Policy 2026-10-07.2
EXT-IGR3-00002
Document grade
Review required
C10: No endotoxin (bacterial toxin) test is reported, and an injectable needs one, so the grade stops at D.
Document check: flag.
Lab record: not confirmed.
Graded Oct 14, 2026 · Grader 0.4.9 · Policy 2026-10-07.2
AF87555243
| COA grade | Printed lab | Certificate | |||
|---|---|---|---|---|---|
| Skye Peptides Lot: IGF26-01-001 vial 2 | Document grade Why this result?C10: No endotoxin (bacterial toxin) test is reported, and an injectable needs one, so the grade stops at D. Document check: flag. Lab record: not confirmed. Graded Oct 14, 2026 · Grader 0.4.9 · Policy 2026-10-07.2 | MZ Biolabs | Mar 3, 2026 | 99.11%99.0–99.49% | View COA |
| Wholesale Peptide Lot: EXT-IGR3-00002 | Document grade Why this result?B8: Key details are missing from the certificate: lot number and analysis or report date. Document check: flag. Lab record: not confirmed. Graded Oct 14, 2026 · Grader 0.4.9 · Policy 2026-10-07.2 | SR BIO LABS | Jun 22, 2025 | 99.08%99.0–99.49% | View COA |
| Peptide Pros Lot: AF87555243 | Document grade Review required Why this result?C10: No endotoxin (bacterial toxin) test is reported, and an injectable needs one, so the grade stops at D. Document check: flag. Lab record: not confirmed. Graded Oct 14, 2026 · Grader 0.4.9 · Policy 2026-10-07.2 | MZ Biolabs | Oct 19, 2022Older record | 99.7%99.5%+ | View COA |
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