Based on the success of creatine, other substances have been introduced to the commercial market in the hopes of becoming the "new creatine." One such supplement was HMB, a metabolite of the amino acid, leucine. Initial studies of HMB, almost exclusively published by University of Iowa scientists who had discovered and applied for a use patent on HMB, found that HMB appeared to offer anti-catabolic effects in muscle that resulted in increased muscle strength and recovery. These studies,however, all involved untrained college students. When later studies were done using more experienced subjects, HMB flopped miserably. It didn't work any better than a placebo in increasing muscle strength and recovery. Since then, HMB has been shown to be useful for those new to weight-training and for older people. But initial ads for HMB declared that it"worked like Deca!" a reference to Deca-Durabolin, an injectable anabolic steroid.
About a decade ago, University of Florida scientists developed an amino acid-based product that was again hailed as the next great bodybuilding supplement. This supplement consisted of glycine, an amino acid;arginine, another amino acid, and alpha-ketoisocaproic acid, which is a step above HMB in the metabolism of the essential amino acid, leucine. The new substance went by the acronym 'GAKIC." Two studies examined the ergogenic effects of GAKIC during high intensity exercise, with one study involving maximal isokinetic leg extensions, and the other five repeated wind sprints of 10 seconds each on a stationary cycle. The study that focused on leg extensions found a 28% increase in muscle force production, with a 12% increase in total muscle work capacity when compared to a placebo. The stationary cycling study likewise also showed a significant increase in power output in subjects who ingested GAKIC compared to those who ingested a placebo. The two studies had one thing in common besides testing the effect of GAKIC: All the subjects in both studies were untrained college students. In this sense, the findings were similar to those of early HMB studies.
As to how GAKIC produced its ergogenic effect, the prevailing theory was that the components of GAKIC had the ability to rapidly detoxify the accumulation of ammonia in working muscles. Ammonia is produced during intense exercise by the breakdown of purine nucleotides, such as those contained in ATP, as well as the breakdown of amino acids. A large increase of ammonia in working muscle is associated with fatigue onset. So it makes sense that reducing ammonia increases during intense exercise should make muscles more efficient.
But a new study again tested GAKIC, but this time the study used 10 trained, experienced cyclists. The cyclists ingested 11.2 grams of GAKIC or a placebo in a controlled, double-blind and randomized manner, 45 minutes before engaging in 10 sprints of 10 seconds each, separated by 50 second rest intervals on a stationary bike. This design was almost identical to one of the two initial GAKIC studies that showed an ergogenic effect.The updated results showed no differences in mean or peak power, or fatigue between those who ingested GAKIC compared to those who ingested a placebo.As such, this study duplicated the previous findings about HMB: it may work in those with no training experience, but fails to do anything at all in more experienced trainees.
And similarly to HMB, GAKIC is not cheap. The list price for a product called "GAKIC Hardcore" sold by Iovate or MuscleTech is $79.99, but the typical online price is $51.95, still rather expensive for a product that doesn't work for anyone with training experience. MuscleTech quickly secured the exclusive right to sell GAKIC from the University of Florida scientists who developed it and held the use patent soon after the initial two studies were published about GAKIC. I was sent the product right after it became available. The first thing I noticed was that it seemed to work for only about four days, then nothing. I tried it again, twice more with a week separation between usage, and the same thing happened. I now believe that my first impression of efficacy for four days was, in fact, a placebo effect. I believed it would decrease fatigue during my training, and it did--for four days.
If there is a lesson to be learned about GAKIC it's this: don't be swayed by the publication of only two studies into buying any product. Also be aware that what works for untrained college students, or anyone else who is not experienced, may not produce the same results in those with more training experience. And for Heaven's sake, although GAKIC at least featured human subjects, don't fall prey to buying an expensive supplement that has only either in vitro (isolated cell studies) or animal studies to "prove" its efficacy. These don't mean a thing in relation to human usage, and more often than not, often don't pan out when tested in intact human bodies.
Beis L, et al Failure of glycine-arginine-a-ketoisocaproic acid to improve high intensity exercise performance in trained cyclists.Int J Sports Nut Exercise Metabol 2010: in press.
©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited
