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 IGF-1 products is banned by the United States Anti-Doping Agency, World Anti-Doping Agency, and most professional sports organizations. IGF-1 is also on the OPSS list of DoD-prohibited substances, so Military Service Members should avoid products with this ingredient. IGF-1 falls within the class of “peptide hormones,” and supplemental use can have 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 3 June 2019