IGF-1 or Insulin-like Growth Factor 1

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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. It is also called somatomedin.

During the 1990s, 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 most 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. In 2013, the Alabama Attorney General restrained SWATS Edge Performance Chips LLC from selling IGF-1 deer antler spray and tablets. Samples tested by the Sports Medicine Research and Testing Laboratory in Salt Lake City found the IGF-1 in the products was not from deer and was likely from cows or humans. The complaint cites scientific studies that show increased risks of colorectal, breast and prostate cancer in people with high IGF-1 levels, as well as "damage to eyes, enlarged hearts, hypoglycemia, and hyperglycemia."

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.

The sources of the IGF-1 may be animal or human despite being marketed as coming from deer. The concentrations purported may not be accurate. The method of delivery is also questionable since IGF-1 might not be absorbed into the body topically and if taken in a pill it might be broken down in the stomach or intestines and not absorbed. It is generally given as injections in treating children with disorders it can address. However, perhaps a worse situation exists if the products actually do increase IGF-1 levels in the body, as that carries many health risks.

These products are unregulated, and neither their safety nor effectiveness is known.

Health Risks of Increased IGF-1 Levels

If the performance enhancement products actually contain IGF-1 and you can absorb it into your body, it has many actions beyond what is desired for building muscles and recovering from injuries. Taking IGF-1 in sufficient quantities carries many known risks, including cardiac, neuromuscular, and endocrine/metabolic problems.

A summary of epidemiological evidence says that the anabolic signals of IGF-1 can promote tumor development in two ways, by inhibiting cell death and stimulating cell proliferation. Both of these actions can give tumor cells more of a chance to live, reproduce, and invade other tissues. Risks for cancers of the colon, pancreas, endometrium, breast, and prostate increase as you have more circulating IGF-1 in your system.

Natural levels and activity of IGF-1 are influenced by how much food is eaten, whether a diet is high in animal protein, and your physical activity levels.

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  1. National Institutes of Health. Office of Dietary Supplements. Dietary Supplements for Exercise and Athletic Performance. Updated October 17, 2019.

  2. Kaaks R. Nutrition, insulin, IGF-1 metabolism and cancer risk: a summary of epidemiological evidence. Novartis Found Symp. 2004;262:247-260.