Last updated October 21, 2026. Approval line checked October 21, 2026. No compounding source date is assigned.
FDA status
Not approved
Not approved. This record is not an FDA-approved drug product. Approval, where it exists, is specific to a drug product, indication, and route.
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Evidence tier
Animal Only. The tier is the highest indexed study type. It is not a safety rating and it is not an FDA approval. Confidence score 2/5. 890 PubMed citations indexed.
Products sold as "research use only" are not approved for human use. FDA warning.
Long R3 analog of IGF-1 with extended half-life (~20 hrs) that bypasses normal IGF binding proteins to activate IGF-1R-mediated PI3K/Akt/mTOR growth signaling.
What the literature studies
Muscle Hypertrophy & Growth Factor Signaling
Evidence tier
Animal Only
Compounding record
Status not verified
Status not verified. No product-specific FDA primary source is recorded for this entry. FDA approval and compounding eligibility are not verified. Research information is not evidence of FDA approval. Approval, where applicable, is specific to a drug product, indication and route. Research information is not evidence of FDA approval. Approval, where applicable, is specific to a drug product, indication and route.
Regulatory source not verified; no checked date is assigned.
potential for hypoglycemia, tumor promotion risk, and acromegaly-like effects at high.
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Educational only. Not medical advice. This page does not give doses or sourcing. See the medical and editorial disclaimer.
IGF-1 LR3 (Long Arg3 IGF-I) is a research IGF-1 analog used in lab and veterinary literature; it is not the FDA-approved drug Increlex (mecasermin), and gray-market bodybuilding vials are unapproved with unverified contents.
Long R3 IGF-I is an IGF-1 analog with an arginine substitution at position 3 and an N-terminal extension designed to reduce IGF-binding-protein interaction in experimental systems [R2][R3]. It is distinct from recombinant human IGF-1 (mecasermin).
IGF-1 LR3 is not FDA-approved. The FDA-approved IGF-1 product is Increlex (mecasermin) for growth failure in children with severe primary IGF-1 deficiency (and related labeled uses) - a different molecule and labeled drug [R1]. WADA and anti-doping literature treat IGF analogs as prohibited substances; black-market products labeled Long-R3-IGF-I have been analytically detected [R3]. peptidex.ai does not sell or link to sellers.
No FDA-approved clinical program establishes IGF-1 LR3 for muscle growth, injury recovery, or anti-aging in healthy adults. Human therapeutic evidence for IGF-1 as a class centers on mecasermin in labeled pediatric IGF-1 deficiency - not LR3 [R1].
Long-R3-IGF-I has been used in cell culture and animal physiology studies (e.g., intestinal/gut and growth-axis experiments) [R2]. Animal and in-vitro results are not evidence of safe human performance use.
IGF-axis stimulation can affect glucose metabolism and theoretically neoplasia risk; product-specific human safety for LR3 is not established. Gray-market injectables: identity, potency, and sterility unverified [R3].
No FDA approval of IGF-1 LR3 identified. Increlex remains the US approved rhIGF-1 product for its labeled pediatric indications [R1].
Last checked 2026-10-27
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