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What Is IGF-1 (Insulin-like Growth Factor 1)?

IGF-1 is a Banned Performance-Enhancing Drug


Updated June 18, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

IGF-1 (Insulin-like growth factor 1) is a naturally-occurring polypeptide protein hormone, similar to insulin, that is primarily produced by the liver. IGF-1 plays an important role in stimulating growth during childhood and helps build and repair muscle tissue in adults.

During the 1990's, researchers began studying the benefits of IGF-1 supplementation, which reportedly included improvements in muscle hypertrophy, tissue repair and recovery times, among others. Soon, a variety of manufacturers were marketing products containing IGF-1 and labeled as nutrition supplements.

IGF-1 is considered a performance-enhancing drug and is included on the 'Banned Substance Lists' of the majority of organized and professional sports organizations, including the National Football League, the International Olympic Committee and the World Anti-Doping Agency.

Deer Antler Spray and IGF-1

Deer antler spray, which contains IGF-1, made media headlines in 2011 after reports surfaced that Ray Lewis, a linebacker for the Baltimore Ravens, was connected with the product.

The Ultimate Spray and IGF-1

Another spray that contains IGF-1, called "The Ultimate Spray," has also made headlines for being used by several NFL players as an alternative to steroids.

These products are unregulated, and neither their safety nor effectiveness is known. In addition, taking IGF-1 in sufficient quantities carries many known risks, including cardiac, neuromuscular, and endocrine/metabolic problems.


The World Anti-Doping Agency, The 2011 Prohibited List International Standard [pdf]

NFL Players Association, [http://www.nflplayers.com/About-us/Rules--Regulations/Player-Policies/Banned-Substances] Banned Substance List, 2011.

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