In stock


1 mg per vial
Purchase this product now and earn 80 Points!

This product is prepared for LABORATORY RESEARCH USE ONLY and may not be used for other purposes.


Free & Fast




Physical Appearance Fine White Lyophilized Powder
Stability Lyophilized protein is to be stored at -20°C. It is recommended to aliquot the reconstituted (dissolved) protein into several discrete vials in order to avoid repeated freezing and thawing. Reconstituted protein can be stored at 4°C


CAS 143045-27-6


Insulin Like Growth Factor (IGF)-1 LR3 is an 83 amino acid residue analogue of native IGF-1, which has been documented as an agent for inducing hyperplasia and stimulating cellular proliferation1. By modifying the original IGF-1 polypeptide – a 70 amino acid residue sequence – with a 13 amino acid b-terminus extension and a substitution of Arg for Glu at position 3 (hence the synonym Long Arg3)2, IGF-1 LR3 introduces enhancements to IGF-1’s biological activity while improving its structural stability, and therefore, residence time, in vivo.

Animal studies have demonstrated the ability of IGF-1 LR3 to bind directly to natural IGF receptors and stimulate new tissue formation, while inhibiting apoptosis (programmed cell death) in existing tissues3. Especially at muscle cell sites, IGF-1 species are noted to enhance amino acid recruitment, augment the synthesis of new proteins while minimizing the digestion of intracellular protein as a fuel source. Instead, fat deposits are used as energy sources while IGF-1 species are biochemically active4.

Product Comparison

IGF-1 is a key factor in mediating the growth-promoting effects of growth hormone (GH) 5. This particular IGF-1 species was developed in order to avoid interaction with IGFBPs (Insulin Like Growth Factor Binding Proteins), which are known to hinder the activity of native IGF-1 over time6. By avoiding this interplay, IGF-1 LR3 is capable of achieving a very long half-life, which leads to its utility as a long-acting, extremely active facilitator of GH-stimulated anabolic activity.

Compared to IGF-1 DES, IGF-1 LR3 is considered to be less active as a stimulant of acute hyperplasia. This said, IGF-1 LR3 with its sustained in vivo activity is able to induce hypertrophic activity over long periods of time, whereas native IGF-1 and IGF-1 DES lack this functionality7.

IGF-1 LR3 and IGF-1 DES have both been demonstrated as more active biological agents relative to native IGF-1 when it comes to stimulating new cell growth in animal trials.

Studies investigating the effects of concurrent IGF-1 species and GH (or GH secretagogue) administration have identified their synergy5 in promoting the development of lean body mass and reduction of fat stores in test subjects.


Insulin Like Growth Factor-1 LR3; IGF-1 Long R3; IGF-1 Long Arg3;

Somatomedin C analogue; Itropin

Peer-Reviewed Sources:

  1. Musarò, A., McCullagh, K., Paul, A., Houghton, L., Dobrowolny, G., Molinaro, M., & Rosenthal, N. (2001). Localized Igf-1 transgene expression sustains hypertrophy and regeneration in senescent skeletal muscle. Nature genetics, 27(2), 195-200. ↩︎
  2. Wangsa-Wirawan, N. D., Colby, C. B., O’Neill, B. K., & Middelberg, A. P. J. (2000). The Characteristics of Protein Inclusion Bodies: Physicochemical Properties of an Insulin-like Growth Factor Analog-Long-R3-IGF-1. ↩︎
  3. Tavakkol, A., Elder, J. T., Griffiths, C. E., Cooper, K. D., Talwar, H., Fisher, G. J., & Voorhees, J. J. (1992). Expression of growth hormone receptor, insulin-like growth factor 1 (IGF-1) and IGF-1 receptor mRNA and proteins in human skin. Journal of Investigative Dermatology, 99(3), 343-349. ↩︎
  4. LeRoith, D., & Yakar, S. (2007). Mechanisms of disease: metabolic effects of growth hormone and insulin-like growth factor 1. Nature Clinical Practice Endocrinology & Metabolism, 3(3), 302-310. ↩︎
  5. Berryman, D. E., Christiansen, J. S., Johannsson, G., Thorner, M. O., & Kopchick, J. J. (2008). Role of the GH/IGF-1 axis in lifespan and healthspan: lessons from animal models. Growth Hormone & IGF Research, 18(6), 455-471. ↩︎
  6. Francis, G. L., Ross, M., Ballard, F. J., Milner, S. J., Senn, C., McNeil, K. A., & Wells, J. R. E. (1992). Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency. Journal of molecular endocrinology, 8(3), 213-223. ↩︎
  7. Ding, H. U., Gao, X. L., Hirschberg, R., Vadgama, J. V., & Kopple, J. D. (1996). Impaired actions of insulin-like growth factor 1 on protein Synthesis and degradation in skeletal muscle of rats with chronic renal failure. Evidence for a postreceptor defect. Journal of Clinical Investigation, 97(4), 1064. ↩︎

All literature, information, and data, provided on this website are for informational and educational purposes only.

Accurate research is our priority.

Same Day Shipping
We offer same day shipping on all orders of in stock items placed before 12:00pm EST.
Dedicated Service
Our team is readily available to assist with all of your customer service requests.
Free Shipping
We've got you covered! Free shipping is available on any order over $50.
Earn Rewards
Earn points every time you buy from us and use them towards future orders!
Extreme Peptide vial with logo and indicators