Leucine’s primary mechanism of action is via activation of Mammalian Target of Rapamycin (mTOR) which is a signaling molecule that signals the body to synthesize protein. To put it simply, Leucine activates mTOR which in turn stimulates protein synthesis.
One of the most commonly cites studies was published in the “International Journal of Sports Physiology and Performance” and found that 12 weeks of Leucine supplementation (4g/day) significantly increased 5-rep max in previously untrained (but healthy) male subjects, compared to the placebo group.
Leucine has also been shown, in multiple studies, to preserve muscle mass in individuals with certain diseases characterized by muscular wasting, further establishing Leucine as a potent anti-catabolic agent, and indicating that it is particularly useful for those with inadequate protein intake (during fasting).
Performix has chosen a rather odd dose of Leucine, 3525mg, which is more or less within the effective (clinical) range and may very well induce muscle protein synthesis.
Leucine does appear to be the most critical in regards to muscle protein synthesis, but Isoleucine has its own benefit pertaining to glucose uptake. In rat studies, Isoleucine has been shown to lower blood glucose and increase glucose uptake into muscle cells. While the effect of Isoleucine (in isolation) on muscle glucose uptake has not been studied in humans, BCAAs in general due appear to increase glucose uptake, and based on the rat studies this may be due to Isoleucine more so than the others.
ISO 9:2:2 contains 762.5mg of Isoleucine per serving.
Valine appears to possess the least unique benefit out of the three, but there are claims circulating that Valine may reduce mental exercise-induced fatigue by reducing the amount of Tryptophan available for Serotonin synthesis.
A 2001 study concluded that Valine lowered the amount of exercise-induced 5-HT (Serotonin) in mouse hippocampuses. During exercise Tryptophan is transported to the brain where it is converted into Serotonin. It is hypothesized that Serotonin is responsible for mental fatigue. It has also been established that BCAA directly compete with tryptophan for the same pathway to the brain, and therefore may reduce the amount of Tryptophan available for Serotonin production.
This would explain certain anti-fatigue effects of BCAA supplementation noted in a few studies. However, the claim that Valine is solely responsible for this effect is unsubstantiated by human studies. Given the current literature, it appears more likely that BCAAs in general help to attenuate fatigue.
ISO 9:2:2 contains 762.5mg of Valine per serving.
Citrulline is usually found in pre-workout supplements, as it has been shown in multiple studies to imrove exercise performance. However, Xtend GO contains 1g of Citrulline which is much less than what has been used clinically. In the context of Xtend GO Citrulline may serve a different purpose.
There is preliminary evidence to suggest Citrulline may act in a synergistic manner with Leucine by positively affecting Leucine’s stimulation of mTOR, which is why we like seeing it in amino-based supplements.
Performix does not disclose the exact dose of Citrulline Malate present in the ISO 9:2:2 formula but, based on a 3917mg proprietary blend, we’d estimate maybe 1-2g tops.
Glutamine is a non-essential amino acid (your body can make it) that is involved in a variety of bodily functions, from immune health, to providing a back-up fuel-source for the brain. Aside from its general physiological roles, supplemental Glutamine has shown a lot of promise when it comes to fighting exercise induced immune system suppression.
Our immune systems ultimately benefit from regular exercise, but in the short-term, exercise actually temporarily lowers our immune defenses, thus making us more susceptible to infection during that time-frame. This temporary compromise of the immune system has been proven to correlate with lower levels of glutamine.
For this reason, it is suggested that increased uptake of glutamine may help keep the immune system strong post-exercise. In addition, lower glutamine levels have been recorded in over-trained athletes, suggesting that higher levels of glutamine may help to prevent overtraining.
As with Citrulline, Performix does not disclose the amount of Glutamine in the ISO 9:2:2: formula.
Betaine (also known as Trimethylglycine) is the amino acid Glycine with the addition of three methyl groups attached. Betaine is alleged to increase power output and strength by increasing cellular swelling, a phenomenon well established with Creatine supplementation, which can drastically reduce the damaging effect of outside stimuli (such as exercise) on the working muscle. So far, Betaine has been investigated in several human studies, and has had some pretty encouraging results in most.
Feel free to read this article on Betaine, as it covers all the studies regarding performance enhancement.
It’s not clear how much Betaine is present in one serving of ISO 9:2:2.
Taurine is relatively pervasive as a pre-workout/recovery ingredient at this point because it has consistently been demonstrated to reduce oxidative damage in muscle tissue.
In a 2011 study from “Cell Biochemistry and Function” Taurine was shown to significantly reduce exercise-induced oxidative stress in skeletal muscle.
These findings were consistent with those of an earlier (2004) study, published in “Amino Acids” which showed that Taurine may decrease exercise induced DNA damage, as well as “enhance the capacity of exercise due to its cellular protective properties”.
A recent 2013 study, also from “Amino Acids” noted a 1.7% improvement in 3k-time trial of runnersafter supplementing with Taurine, and these findings were further corroborated in a 2013 study from “Applied Physiology, Nutrition, and Metabolism “ in which Taurine supplementation was able to decrease muscle damage and increase strength (slightly).
Performix does not disclose the precise dose of Taurine present in ISO 9:2:2.
Astragin is a patented combination of Panax Ginseng and Astragalus. Although each of these components has their own set of potential benefits, Performix’s uses Astragin as an absorption enhancer. Astragin has been shown to enhance the absorption of Citrulline in vitro, but not in a living system at this time.
The Bottom Line
ISO 2:1:1 isn’t much different from other BCAA-centric formulas we’ve seen, although it does contain a few other things which ultimately may enhance the recovery/performance aspect of the product. Performix doesn’t explain the reasoning behind the 9:2:2 ratio, but it makes sense given that Leucine is the most potent with regards to stimulating muscle protein synthesis (so no complaints there). Unfortunately, as with most Performix products, multiple servings may be required to acheive effective doses of key ingredients (unless you buy into the whole enhanced absorption thing),
Still don’t know which amino supplement is right for you? Check out our Best Amino Acid Supplements List!
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