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IGF-1 LR3 Results: What Studies Measured and When

What published studies measured for IGF-1 LR3, when those outcomes were measured, and what is still unproven.

Medically reviewed by Juan Pablo Frías, MD · · DisclosureIGF-1 analogUpdated

What studies measured

Each outcome below comes from a published study, with its type and size, strongest design first. Animal and cell results are labelled as such and are not human results.

IGF-1 LR3 outcomes in published studies
OutcomeResultStudy typeSource
Black-market product compositionA black-market injection vial contained a His-tagged IGF-I variant; its effects in humans are not described.Human case reportGrowth hormone & IGF research 2010, PMID 20675162
Regulatory status and evidence for physique claimsThe review notes no regulatory approval for physique- or performance-related indications of these peptides, including the long-acting IGF analogue.ReviewFrontiers in endocrinology 2026, PMID 42395176
Fetal growthOne week of IGF-1 LR3 did not improve growth in growth-restricted fetal sheep.Animal · sheep (not a human result)n = 14American journal of physiology. Endocrinology and metabolism 2025, PMID 39679943
Body composition and cognitionIntranasal LR3-IGF-1 improved body composition (not specified in the abstract) in male 5XFAD mice but did not significantly change cognition.Animal · mouse (not a human result)Journal of Alzheimer's disease 2025, PMID 39610283
Insulin secretionFetal plasma insulin fell with infusion, and insulin during the hyperglycemic clamp was 66% lower than control.Animal · sheep (not a human result)n = 10Journal of developmental origins of health and disease 2023, PMID 37114757
Daily weight gainIn the second 9 days, LR3IGF-I-infused neonatal pigs gained 457 g/d versus 386 g/d for controls.Animal · pig (not a human result)The British journal of nutrition 2002, PMID 12067429
Clearance from wound fluidHalf-life in wound fluid was 563 min for LR3-IGF-I versus 872 min for IGF-I, 861 for IGF-II and 324 for insulin.Animal · rat (not a human result)The American journal of physiology 1999, PMID 10198302
Growth performanceA four-day infusion of 180 micrograms/kg/day LR3IGF-I decreased average daily gain, food intake and plasma IGFBP-3, IGF-I and insulin in pigs.Animal · pig (not a human result)The Journal of endocrinology 1997, PMID 9488001
Endogenous GHMean plasma GH fell by 23% and the area under the GH peaks by 60%.Animal · pig (not a human result)The Journal of endocrinology 1997, PMID 9488001
Overall growthFractional weights of adrenals, gut, kidneys and spleen increased with LR3IGF-I, but overall growth was not stimulated.Animal · guinea pig (not a human result)The Journal of endocrinology 1995, PMID 7561636
Body and gut weightLR3IGF-I (not IGF-I) increased body weight and wet weight of small and large intestine by 20% versus controls; muscle was not measured.Animal · rat (not a human result)Gut 1995, PMID 8549937
Carcass proteinLR3-IGF-I had no positive effect on carcass protein accretion in tumour-bearing rats.Animal · rat (not a human result)The Biochemical journal 1994, PMID 8053901
Growth in diabetic ratsThe IGF-I variants were 2.5-3 times more potent than IGF-I at restoring growth in diabetic rats.Animal · rat (not a human result)The Biochemical journal 1993, PMID 7683875
Muscle protein synthesisAll IGF peptides raised muscle protein-synthesis rates and RNA levels by up to 50%, IGF-I least.Animal · rat (not a human result)The Biochemical journal 1993, PMID 7683875
  • No human trial of IGF-1 LR3 has been published in PubMed as of 2 October 2026. The literature is cell-culture supplement work and animal studies (rat, guinea pig, pig, sheep, mouse). The only human-related paper is a case report of a black-market vial (20675162).
  • Animal results are mixed: LR3IGF-I increased growth in diabetic rats and neonatal pigs but did not stimulate overall growth in guinea pigs, reduced growth and endogenous GH and IGF-I in finisher pigs, did not improve growth in growth-restricted fetal sheep, and increased tumour growth in tumour-bearing rats.
  • Almost all LR3 literature is cell-culture use as a media supplement. No evidence in people exists for muscle growth, bodybuilding or GH-related goals.
  • IGF-1 LR3 is not an approved drug and has no FDA label. No stability study was found.

Typical timeline

When measurable changes appeared in studies of IGF-1 LR3: not reported in study abstracts (PubMed search, 2 Oct 2026).

Before-and-after photos

We don't publish before-and-after photos. They can't be verified, rarely show dose, diet or other drugs, and only the most dramatic results get posted.

Common questions

How long does IGF-1 LR3 take to work?

The study abstracts we summarised for IGF-1 LR3 do not report when outcomes were measured (PubMed search, 2 Oct 2026).

Do you show IGF-1 LR3 before and after photos?

No. Photos can't be verified, rarely show dose, diet or other drugs, and only the most dramatic ones get posted. We summarize measured outcomes instead.

More on IGF-1 LR3

DosageDoses used in published studies, with the source for each.CalculatorVial, water and dose to syringe units.Side effectsWhat labels and studies report, and what is unknown.PricePrice per mg and per week from dated listings. No vendor links.How to injectSites, syringe types and hygiene, step by step.1 mg vialConcentration and unit tables for the 1 mg size.

Sources

  1. 1Detection of His-tagged Long-R³-IGF-I in a black market product.Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society · 2010PMID 20675162Accessed 2 Oct 2026
  2. 2The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration.Frontiers in endocrinology · 2026PMID 42395176Accessed 2 Oct 2026
  3. 3IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep.American journal of physiology. Endocrinology and metabolism · 2025PMID 39679943Accessed 2 Oct 2026
  4. 4Intranasal long R3 insulin-like growth factor-1 treatment promotes amyloid plaque remodeling in cerebral cortex but fails to preserve cognitive function in male 5XFAD mice.Journal of Alzheimer's disease : JAD · 2025PMID 39610283Accessed 2 Oct 2026
  5. 5Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets.Journal of developmental origins of health and disease · 2023PMID 37114757Accessed 2 Oct 2026
  6. 6Insulin-like growth factor-I and analogues increase growth in artificially-reared neonatal pigs.The British journal of nutrition · 2002PMID 12067429Accessed 2 Oct 2026
  7. 7Clearance of IGFs and insulin from wounds: effect of IGF-binding protein interactions.The American journal of physiology · 1999PMID 10198302Accessed 2 Oct 2026
  8. 8Long [R3] insulin-like growth factor-I reduces growth, plasma growth hormone, IGF binding protein-3 and endogenous IGF-I concentrations in pigs.The Journal of endocrinology · 1997PMID 9488001Accessed 2 Oct 2026
  9. 9Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig.The Journal of endocrinology · 1995PMID 7561636Accessed 2 Oct 2026
  10. 10Administration of insulin-like growth factor-I (IGF-I) peptides for three days stimulates proliferation of the small intestinal epithelium in rats.Gut · 1995PMID 8549937Accessed 2 Oct 2026
  11. 11Effects of insulin and insulin-like growth factors on protein and energy metabolism in tumour-bearing rats.The Biochemical journal · 1994PMID 8053901Accessed 2 Oct 2026
  12. 12Insulin-like growth factor-I and more potent variants restore growth of diabetic rats without inducing all characteristic insulin effects.The Biochemical journal · 1993PMID 7683875Accessed 2 Oct 2026
  13. 13PubMed search: ("Long R3"[tiab] OR (LR3[tiab] AND (IGF[tiab] OR "IGF-1"[tiab] OR "IGF-I"[tiab] OR "insulin-like growth factor"[tiab]))) (109 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  14. 14PubMed search: ("Long R3 IGF-I"[tiab] OR "LR3 IGF-I"[tiab] OR "IGF-I LR3"[tiab] OR "LR3-IGF-I"[tiab] OR "IGF-1 LR3"[tiab] OR "LR3 IGF-1"[tiab] OR "[Long R3]IGF-I"[tiab]) AND (rat[tiab] OR rats[tiab] OR mice[tiab] OR infusion[tiab] OR muscle[tiab] OR pigs[tiab] OR in vivo[tiab]) (38 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  15. 15PubMed search: "long R3 IGF"[tiab] OR "long-R3 IGF"[tiab] OR "LR3-IGF"[tiab] OR "LR3 IGF"[tiab] OR "R3 IGF-I"[tiab] (95 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  16. 16PubMed search: ("LR3"[tiab] AND IGF[tiab]) AND (half-life[tiab] OR pharmacokinetic*[tiab] OR clearance[tiab]) (2 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026

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