Encyclopedia entry · GH Secretagogues
IGF-1 LR3
Long-R3 Insulin-like Growth Factor 1
IGF-1 LR3 is a synthetic analogue of Insulin-like Growth Factor 1 with two modifications: a 13-amino-acid N-terminal extension (the Long peptide tag), and a substitution at position 3 (Glu to Arg). These changes dramatically reduce binding to IGF-binding proteins (IGFBPs), extending in-vivo half-life from minutes to roughly 20 to 30 hours.
What the molecule is
- · Synthetic IGF-1 variant with arginine substitution at position 3 and N-terminal extension.
- · Reduced affinity for IGFBPs (Insulin-like Growth Factor Binding Proteins) extends half-life.
- · Mitogenic and anabolic in laboratory cell-culture and animal-model work.
- · Distinct from clinical IGF-1 (Mecasermin), which is the unmodified hormone used in paediatric IGF deficiency.
What the literature shows
- · Originally engineered for laboratory cell-culture growth-supplement use.
- · Animal-model evidence for muscle protein synthesis and hypertrophy.
- · Insulin-like hypoglycaemia effects reported in animal work.
- · No phase III human trials. Not licensed by any Western regulator.
UK regulatory status
- · Not a controlled drug under the Misuse of Drugs Act 1971.
- · Not scheduled under the Psychoactive Substances Act 2016.
- · No UK marketing authorisation as a medicine.
- · Research-tier in all Western jurisdictions.
Where UK researchers source IGF-1 LR3
See CoA Trust Index →Ranked by CoA Trust tier (strong, partial, weak). Editorial commentary on retailers that list IGF-1 LR3 or compounds in the same category. We earn a referral fee when readers click through and convert.
Researchers wanting named-stack bundles (Wolverine, KLOW, Glow) and CoAs that can be QR-verified to a named third-party lab.
Research peptide retailer · Wolverine Stack £29.99, BPC-157 single from £14.99
Nottingham-based research peptide retailer (Bio Research Ltd, since 2024). Bundles and stacks are the hero SKU (Wolverine BPC-157 + TB-500, Tesamorelin + Ipamorelin 3:1, KLOW, Glow). Janoshik third-party CoAs published per batch with QR-code verification. 10-vial bulk packs alongside singles. Wholesale tier above 11 vials.
Best for per-batch CoA library
Research peptide retailer · BPC-157 5mg £13.99, TB-500 5mg £36
Long-established UK research peptide supplier. 12 years trading, 15,000+ customers. Operates a public CoA subdomain (coa.purepeptidesuk.com) with downloadable per-batch certificates linked from every PDP. Dual-tier purity (Standard vs Premium with endotoxin LAL + heavy-metal testing on Premium).
Researchers who want transparent third-party HPLC batch documents and a less hyped brand voice.
Research peptide retailer · Per peptide, varies
UK research peptide retailer with third-party HPLC plus transparent batch documentation. Plays the credibility lane alongside Pure Peptides UK and Tide Labs.
Researchers who weight UKAS lab accreditation specifically and want the loudest external-verification claim in the segment.
Research peptide retailer · Per peptide, varies
UK research peptide retailer leaning on UKAS-verified HPLC as the sole-in-UK trust claim. Narrower catalogue than UKPeptides or Pure Peptides UK but the lab-verification angle is the loudest in the segment.
Best for classic peptides catalogue
Research peptide retailer · Per peptide, varies
Long-trading UK research peptide retailer (2012). Heavy on classic compounds (BPC-157, TB-500, GHK-Cu, CJC-1295, Ipamorelin, MOTS-c). No GLP-1, no cosmetic line. CoA gated via on-site contact form (request lab report per product). On-site CusRev reviews 5.0 average, not Trustpilot. Reconstitution calculator on-site.
Buyers who want personal owner-accountability via WhatsApp and prefer CoAs visible in product images rather than gated. Strong stack catalogue.
Research peptide retailer · BPC-157 from £18.99, Wolverine Stack discounted
Family-run Newcastle research peptide retailer (Rian, Victoria, Leah Redman). Owner-fronted WhatsApp on every page. CoAs photographed into the product gallery (COA in image) rather than gated. Heavy on named-stack bundles (Wolverine, Hulk, Ultimate Bundle). Crisp live chat sitewide. Personal accountability is the trust play.
Where to learn more
- · PubMed search: "IGF-1 LR3" and "Long R3 IGF-1".
- · Francis GL et al. original development papers.
- · Our function hub: GH Secretagogues.
PeptideClear does not sell, dispense, prescribe, or recommend IGF-1 LR3 for any specific person. This page is editorial commentary on the published preclinical and clinical research literature and the UK retail landscape.
Read our full methodology and how we are funded.
Ready to buy
Buy IGF-1-LR3 in the UK
UK retailers compared by price, Trust Index, and CoA practice. Editorial commentary only. Research use only.