The next or perhaps more accurately, the newest generation of performance-enhancing drugs in sport is insulin-like growth factor-1 or IGF-1. The first synthetic version of IGF-1 approved for sale in the United States was Increlex.
To understand Increlex one needs to look at human growth hormone. Human growth hormone is a favorite among athletes and celebrities for its healing powers and anti-aging capabilities. In the liver, hGH converts to insulin-like growth factor-1 promoting growth.
While recombinant human growth hormone been around since the 1980s, synthesized IGF-1 wasn’t approved for use until 2005. In August, 2005, the FDA approved Tercica's IGF-1 drug, Increlex, as replacement therapy for severe primary IGF-1 deficiency.
From the Increlex website:
"For many years, natural growth hormone was the only treatment available for children with short stature. In the 1980s, manmade—or “recombinant”—growth hormone was introduced, but that still did not provide a potential answer for children with severe Primary IGFD since their bodies already produced enough growth hormone. Fortunately, researchers began thinking more about the importance of IGF-1 in the growth process and about new ways to replace this important hormone when it’s missing. The natural outgrowth was manmade IGF-1."
Journalists and scientists have speculated for some time that baseball players and other athletes were likely already using IGF-1. The benefits are even greater than hGH and the side-effects are thought to be less severe (though testing is limited).
In 2002, Lee Sweeney, Professor and Chairman of Physiology at the University of Pennsylvania, and a recognized expert on the subject of the genetic enhancement of skeletal muscle, spoke to CNN with regard to the muscle building and regenerating properties of IGF-1 and touched on athletics.
"I think athletic competition at the world level is going to change. We're going to have competitions essentially with people who have re-engineered their muscles; and all the records in speed and strength events are just going to go by the boards. It's a terrible thing, because it will make a mockery of all the competition of the past."
Much like hGH, IGF-1 has been shown to increase the rate and extent of muscle repair after injury and increase the rate of muscle growth from training. IGF-1 not only aids existing muscle tissue, but it causes an increase in the amount of muscle fibers called hyperplasia.
Hyperplasia is the Holy Grail for athletes, and occurs when muscle fibers actually split, therefore creating more muscle fibers. Hyperplasia combined with extensive training could lead to a super-human breed of athlete.
Increlex is not the only insulin-like growth factor-1 product available in the United States. In December 2005, the FDA also approved IPLEX, Insmed's IGF-1/ IGFBP-3 complex. By delivering the drug in a complex they can get the same effects as far as growth rates but with fewer side-effects.
And there are more IGF-1 drugs on the way. In the last few years, two additional companies Tercica and Insmed compiled enough clinical trial data to seek FDA approval for IGF-1 products. The more drugs available to patients who actually need them, the more easily athletes will be able to get them.
Like Human Growth Hormone, there is no reliable test, either urine or blood, for IGF-1. Performance-enhancing drugs seem to be getting more powerful, less harmful and less detectable simultaneously.