Insulin-like growth factor type 1—commonly known as IGF-1—is a hormone produced naturally, mostly in the liver, and is involved in the human body’s growth and development. IGF-1 also is found in colostrum—the milk produced by humans and other mammals (including pigs and cows) the first few days after giving birth. IGF-1 levels in humans normally rise from birth until late puberty and then begin to decrease.

IGF-1 also can be made in a laboratory, but synthetic IGF-1 is a drug and is not permitted for use as a dietary supplement. So, like other prescription drugs, it cannot be obtained or used legally without a prescription.

Use of products containing IGF-1, other growth factors, and related hormones is banned by the World Anti-Doping Agency and most professional sports organizations. These substances are also on the DoD Prohibited Dietary Supplement Ingredients list, so Service Members should avoid products with these ingredients. Supplemental use of IGF-1 can cause serious side effects.

Oral sprays, lozenges, and other products with IGF-1 are promoted as dietary supplements, and sometimes IGF-1 is represented as “deer velvet extract” (see the OPSS article on deer velvet). However, not all dietary supplements with “IGF” in their name actually contain IGF-1, so it’s important to read labels carefully.


Updated 07 March 2022


Dobolyi, A., & Lékó, A. H. (2019). The insulin-like growth factor-1 system in the adult mammalian brain and its implications in central maternal adaptation. Frontiers in Neuroendocrinology, 52, 181–194. doi:10.1016/j.yfrne.2018.12.002

Guha, N., Nevitt, S. P., Francis, M., Woodland, J. A., Böhning, D., Sönksen, P. H., & Holt, R. I. G. (2015). The effects of recombinant human insulin-like growth factor-i/insulin-like growth factor binding protein-3 administration on body composition and physical fitness in recreational athletes. Journal of Clinical Endocrinology & Metabolism, 100(8), 3126–3131. doi:10.1210/jc.2015-1996

Hoeflich, A., & Meyer, Z. (2017). Functional analysis of the IGF-system in milk. Best Practice & Research Clinical Endocrinology & Metabolism, 31(4), 409–418. doi:10.1016/j.beem.2017.10.002

Munblit, D., Treneva, M., Peroni, D., Colicino, S., Chow, L., Dissanayeke, S., . . . Warner, J. (2017). Immune components in human milk are associated with early infant immunological health outcomes: A prospective three-country analysis. Nutrients, 9(6), Art. E532. doi:10.3390/nu9060532

Rosenbloom, A. L. (2009). Mecasermin (recombinant human insulin-like growth factor I). Advances in Therapy, 26(1), 40–54. doi:10.1007/s12325-008-0136-5

Tan, L., Wei, T., Yuan, A., He, J., Liu, J., Xu, D., & Yang, Q. (2017). Dietary supplementation of astragalus polysaccharides enhanced immune components and growth factors EGF and IGF-1 in sow colostrum. Journal of Immunology Research, 2017, 1–6. doi:10.1155/2017/9253208

U.S. Anti-Doping Agency. (2014). IGF-1 and the World Anti-Doping Agency Prohibited List. Retrieved 28 May 2019 from

U.S. Food & Drug Administration. (2014). Full prescribing information: Increlex. Retrieved 28 May 2019 from

U.S. Food & Drug Administration. (2017). Report on the Food and Drug Administration’s review of the safety of recombinant bovine somatotropin. Retrieved 28 May 2019 from