IGF-1 DES (reported as des(1-3)IGF-I in scientific studies) is a truncated version of naturally occurring IGF-1. The 70 amino acid form of activated IGF-1 is essential for normal human growth and development and acts via IGF-1 receptors to exert an anabolic effect to build muscle, which is why IGF-1 is important in bodybuilding . Low IGF-1 levels are linked to poor growth and a number of metabolic disorders . Multiple tissues inside the body produce IGF-1 and its site of synthesis affects its function. The majority of IGF-1 is made by the liver and is transported to other tissues in the bloodstream, where it acts as an endocrine hormone . Importantly, IGF-1 is a central growth hormone that controls the anabolic growth promoting effect of growth hormone. It also has a growth hormone independent growth-stimulating effect, which is optimised when combined with growth hormone . IGF-1 DES has been specially formulated to lack three amino acids from the end of natural IGF-1, which increases its potency to around ten-fold higher when compared to regular IGF-1 . This increase in potency is due to the fact that IGF-1 DES does not bind to IGF-binding proteins like IGF-1 . Usually, IGF-binding proteins immediately block the growth-promoting activities of IGF-1, but they are unable to bind and block IGF-1 DES. This means that the peptide is free to promote muscle and bone growth and repair and smooth muscle survival [7, 8]. IGF-I DES has been shown to stimulate body growth in a range of tissues in multiple animal studies . Animal studies have also shown that carcass fat was reduced alongside muscle gains . In diabetic animals the modified peptide demonstrated effects throughout the alimentary tract and led to improvements in nutrient uptake . Although no human clinical trials using IGF-1 DES have been carried out, studies have uncovered that the peptide is naturally found in the human brain and brain cell studies have shown that it can protect against brain damage and that it promotes brain growth [11, 12]. IGF-1 DES has a short half-life and is degraded within 5 minutes of administration in humans . The short half-life means that IGF-1 DES 1 mg should be dosed intramuscularly. Up to 100 mcg can be dosed per day and this should be split between either two or four muscles pre-workout. A standard IGF-1 cycle should last four weeks and should be stacked with an anabolic androgenic steroid for optimal results. Side effects of IGF-1 DES may include headaches and nausea since the peptide can induce a hypoglycaemic state. High levels of this hormone have also been shown to promote organ enlargement, so never exceed the recommended dose of 100 mcg per day. References 1. Shavlakadze, T., et al., Reconciling data from transgenic mice that overexpress IGF-I specifically in skeletal muscle. Growth Horm IGF Res, 2005. 15(1): p. 4-18. 2. Cohen, J., et al., Managing the Child with Severe Primary Insulin-Like Growth Factor-1 Deficiency (IGFD): IGFD Diagnosis and Management. Drugs in R&D, 2014. 14(1): p. 25-29. 3. Mauras, N., Growth hormone, IGF-I and growth. New views of old concepts. Modern endocrinology and diabetes series, volume 4. Trends in Endocrinology & Metabolism, 1997. 8(6): p. 256-257. 4. Laron, Z., Insulin-like growth factor 1 (IGF-1): a growth hormone. Molecular Pathology, 2001. 54(5): p. 311-316. 5. Gillespie, C., et al., Enhanced potency of truncated insulin-like growth factor-I (des(1-3)IGF-I) relative to IGF-I in lit/lit mice. J Endocrinol, 1990. 127(3): p. 401-5. 6. Ross, M., et al., Insulin-like growth factor (IGF)-binding proteins inhibit the biological activities of IGF-1 and IGF-2 but not des-(1-3)-IGF-1. Biochemical Journal, 1989. 258(1): p. 267-272. 7. Sunters, A., et al., Mechano-transduction in osteoblastic cells involves strain-regulated estrogen receptor alpha-mediated control of insulin-like growth factor (IGF) I receptor sensitivity to Ambient IGF, leading to phosphatidylinositol 3-kinase/AKT-dependent Wnt/LRP5 receptor-independent activation of beta-catenin signaling. J Biol Chem, 2010. 285(12): p. 8743-5 8. 8.Patel, V.A., et al., Defect in insulin-like growth factor-1 survival mechanism in atherosclerotic plaque-derived vascular smooth muscle cells is mediated by reduced surface binding and signaling. Circ Res, 2001. 88(9): p. 895-902. 9. Ballard, F.J., et al., Des(1-3)IGF-I: a truncated form of insulin-like growth factor-I. Int J Biochem Cell Biol, 1996. 28(10): p. 1085-7. 10. Tomas, F.M., et al., Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats. Biochemical Journal, 1992. 282(Pt 1): p. 91-97. 11. Sara, V.R., et al., Characterization of somatomedins from human fetal brain: identification of a variant form of insulin-like growth factor I. Proceedings of the National Academy of Sciences of the United States of America, 1986. 83(13): p. 4904-4907. 12. Werther, G.A., et al., The role of the insulin-like growth factor system in the developing brain. Horm Res, 1998. 49 Suppl 1: p. 37-40. 13. Pan, W. and A.J. Kastin, Interactions of IGF-1 with the blood-brain barrier in vivo and in situ. Neuroendocrinology, 2000. 72(3): p. 171-8.