Receptor Grade IGF-1 LR3 (1mg)


Size: 1mg
Contents: Receptor Grade IGF-1 LR3 (1mg)
Form: Lyophilized powder
Purity: >99%

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Receptor Grade IGF-1 LR3 Peptide

Receptor Grade IGF-1 LR3 peptide, a polypeptide amino acid also known as Long arginine 3 IGF-1, or LR3-IGF-1, has been suggested to exhibit potential action in lipolysis, protein synthesis, and muscular recovery.(1) Insulin-like Growth factor-1, or IGF-1, is a naturally produced protein composed of 70 amino acids. Structurally similar to insulin, this Receptor Grade IGF-1 LR3 has the potential primarily in regulating cell tissue and body growth and development. There are two synthetic variations of IGF-1; firstly, the synthetic IGF-1, which was developed with the intention of identically mimicking to the natural protein and possibly stimulating similar effects as IGF-1; and second, is Receptor Grade IGF-1 LR3, which is also synthetic in nature, but may exhibit higher efficacy than the natural protein.

Receptor Grade IGF-1 LR3 is a synthetic variant of the naturally occurring IGF-1, which contains an extended N-terminal structure and arginine acid at residue 3. Hence, it is named IGF-1 Long R3.(2) Owing to the altered structure, Receptor Grade IGF-1 LR3 has been suggested to bind poorly with type 1 IGF-1 receptors, potentially increasing blood plasma concentration of the IGF binding proteins.

During the years 1940 to 1950, a growth hormone somatotropin was identified and researched, with scientists eventually positing that it had potential to increase in the sulfate uptake in normal control rat serum. This ‘sulfate factor’ was isolated from the rat serum and named ‘somatomedin.’ An independent study was also conducted to examine the components producing insulin-like activity. During this study, it was suggested that these components were in fact the ‘somatomedins,' resulting in naming these compounds 'insulin-like growth factors'.

Further mutations of the insulin-like growth factors were carried out using gene targeting approaches to potentially increase bioavailability and potency potential. During these mutation studies, Receptor Grade IGF-1 LR3 was synthesized with an additional arginine acid and an extended structure at the N-terminal, producing a protein composed of 80+ amino acids, as opposed to 70 amino acids found in natural IGF-1.(3)


IGF proteins appear to exert potential via binding with IGF-1 receptors, however, researchers posit that these IGF binding proteins, including Receptor Grade IGF-1 LR3 may function either via IGF receptor dependent mechanism or via IGF independent mechanisms.(3)(4)

A study(3) was conducted where an experimental mouse body was created substituting the endogenous IGF-1 with IGF-1 LR3. During this study, it was suggested that upon presenting the Receptor Grade IGF-1 LR3 into this model, the synthetic protein had the potential to quickly clear the serum and distribute into body tissues. At the end of the study, these experimental mice exhibited apparently elevated growth and more strong, robust bones in comparison to the controls. The controls were the normal mice with natural IGF-1 protein levels. Researchers suggest Receptor Grade IGF-1 LR3 has the potential to induce a signaling mechanism in the body, either via autocrine mode (where the tissue cell stimulates itself) or via paracrine mode (where the tissue cell stimulates the nearby cell). The increased potential bioavailability of these autocrine and paracrine IGF-1 LR3 proteins may prove vital to inducing any possible action.

Research and Clinical studies

Receptor Grade IGF-1 LR3 Peptide and IGF-1 Deficiency

There is a 2005 clinical study(6) where the action of rhIGF-1 on subjects with IGF-1 deficiency and growth disorders were studied. RhIGF-1 is the recombinant form of insulin-like growth factor-1, and has researched for its potential in mitigating GH insensitivity. RhIGF-1 is a synthetic form of IGF-1.(11) 45 subjects with natural short stature were enrolled in this controlled study, where rhIGF-1 was presented once daily to all the subjects. The heights of all subjects were measured before and after the study. Researchers suggested that results indicated an average increase in height by 7cm per year in all subjects presented with rhIGF-1. Hence, this study posits that IGF-1 analogs may have a positive potential in growth deficiency.

Receptor Grade IGF-1 LR3 and Metabolic Activity

Studies(7) have suggested that IGF binding proteins, including Receptor Grade IGF-1 LR3, have the potential to induce glucose uptake and thereby glucose metabolism through the possible activation of signaling mechanisms. Since peptides like Receptor Grade IGF-1 LR3, which have been suggested to exhibit poor binding potential toward IGF-1 receptors, they have been reported by some researchers to exert apparently similar effects of glucose metabolism, therefore possibly independent of the protein binding to IGF-1 receptors. As a result of the glucose uptake, IGF-1 LR3 exhibited some potential to induce an overall decrease in the blood sugar levels. This decrease in sugar levels may stimulate adipose tissue lysis of glycogen and triglycerides.

Receptor Grade IGF-1 LR3 and Muscle

This study(8) was conducted on female mice to examine the action of Receptor Grade IGF-1 LR3 on reducing myostatin. Myostatin is a muscle protein that primarily prevents muscle cell differentiation and growth. Reducing the action of myostatin may potentially increase lean muscle mass and reduce the fat mass. In this study(8) it was suggested that different IGF-1 analogs, including IGF-1 LR3, have the potential to counteract with the negative action of myostatin protein, possibly helping to prevent apoptosis and protecting muscle cells. Since Receptor Grade IGF-1 LR3 has an apparently longer half life than IGF-1 (according to the researchers), the potential action of Receptor Grade IGF-1 LR3 was considered.

Receptor Grade IGF-1 LR3 peptide is available for research and laboratory purposes only. Please review and adhere to our Terms and Conditions before ordering.


  1. Growth hormone, athletic performance, and aging. Harvard Health Publishing, Harvard Medical School.
  2. Tomas, F. M., Knowles, S. E., Owens, P. C., Chandler, C. S., Francis, G. L., Read, L. C., & Ballard, F. J. (1992). Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats. The Biochemical journal, 282 ( Pt 1)(Pt 1), 91–97.
  3. Yakar, S et al., 40 YEARS OF IGF1: Insulin-like growth factors: actions on the skeleton (Jul 2018). Journal of Molecular Endocrinology, vol. 61 Issue 1.
  4. Mohan S, Baylink DJ. IGF-binding proteins are multifunctional and act via IGF-dependent and -independent mechanisms. J Endocrinol. 2002 Oct;175(1):19-31.
  5. Anderson, L. J., Tamayose, J. M., & Garcia, J. M. (2018). Use of growth hormone, IGF-I, and insulin for anabolic purpose: Pharmacological basis, methods of detection, and adverse effects. Molecular and cellular endocrinology, 464, 65–74.
  6. IGF1 Deficiency, Recombinant Human Insulin-Like Growth Factor (rhIGF-1) Treatment of Short Stature Associated with IGF-1 Deficiency.
  7. Assefa, B., Mahmoud, A. M., Pfeiffer, A., Birkenfeld, A. L., Spranger, J., & Arafat, A. M. (2017). Insulin-Like Growth Factor (IGF) Binding Protein-2, Independently of IGF-1, Induces GLUT-4 Translocation and Glucose Uptake in 3T3-L1 Adipocytes. Oxidative medicine and cellular longevity, 2017
  8. Naisi Li, Qiyuan Yang, Ryan G. Walker, Thomas B. Thompson, Min Du, Buel D. Rodgers, Myostatin Attenuation In Vivo Reduces Adiposity, but Activates Adipogenesis, Endocrinology, Volume 157, Issue 1, 1 January 2016, Pages 282–291.
  9. William E. Sonntag, Anna Csiszar, Raphael de Cabo, Luigi Ferrucci, Zoltan Ungvari, Diverse Roles of Growth Hormone and Insulin-Like Growth Factor-1 in Mammalian Aging: Progress and Controversies, The Journals of Gerontology: Series A, Volume 67A, Issue 6, June 2012, Pages 587–598,
  10. Mario Thevis (13 December 2010). Mass Spectrometry in Sports Drug Testing: Characterization of Prohibited Substances and Doping Control Analytical Assays. John Wiley & Sons. pp. 252.
  11. Rosenbloom AL. Mecasermin (recombinant human insulin-like growth factor I). Ad Ther. 2009 Jan; 26(1):40-54.

Dr. Marinov

Dr. Marinov (MD, Ph.D.) is a researcher and chief assistant professor in Preventative Medicine & Public Health. Prior to his professorship, Dr. Marinov practiced preventative, evidence-based medicine with an emphasis on Nutrition and Dietetics. He is widely published in international peer-reviewed scientific journals and specializes in peptide therapy research.

Certificate of Analysis

High Performance Liquid Chromatography

Mass Spectrometry

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