STIM-ELITE is a pre-workout by BPI Sports which actually only contains two stimulants, Yohimbine and Caffeine…[Skip to the Bottom Line]
Carnitine is an amino acid which, in addition to forming proteins, is heavily involved with the metabolism of fat for energy. It is required for the proper transport of fatty acids in the mitochondria, where they are oxidized through the process known as “beta-oxidation” for energy. Carnosine deficiency has been shown to hinder the fat burning process (in humans). However, while it has certainly been shown to normalize the fat-burning process in those who are deficient, the implications for healthy individuals are less clear.
A 2002 study, published in “Metabolism”, found that Carnitine supplementation (1g/day) increased fatty acid oxidation rates in humans without Carnitine deficiency. A 2004 study from the same journal found that L-Carnitine supplementation (3g/day) increased fatty acid oxidation in overweight subjects while having no effect on protein synthesis or breakdown. However, a 2005 study, published in the “International Journal for Vitamin and Nutrition Research”, found that Carnitine supplementation failed to influence weight-loss in rats. The results of this study were in-line with an earlier (2002) study in which L-Carnitine supplementation (4g/day) failed to influence fat mass, body mass, or resting lipid utilization in moderately obese women. A more recent (2010) study found that Carnitine supplementation did favorably influence fatty acid utilization in rats, though this study did not measure fat mass post-supplementation.
Ultimately, Carnitine does possess the mechanisms by which it should burn fat (via increased utilization of fatty acids), though supplementation has failed to result in fat-loss in animals and humans. To be fair, the subjects in the above mentioned human study did not pair Carnitine supplementation with high intensity exercise. It is possible, and in fact more likely, that the increased utilization of fatty acids seen with Carnitine supplementation may result in noticeable weight loss when paired with high-intensity exercise, but not with low-intensity exercise or a sedentary state. Since Carnitine’s role is essentially to transport fatty acids to be burned for energy, maintaining optimal Carnitine levels will ensure that the process run smoothly.
Aspartic Acid has been touted as a performance enhancer for decades now, with preliminary research (in rats) suggesting that Aspartic Acid may help remove excess Ammonia during exercise, effectively reducing fatigue. Though some efficacy has been demonstrated, the overall results are mixed and not particularly promising. A 1964 study, published in the “American Journal of Physiology—Legacy Content”, failed to note any significant changes in various performance measures including breathing capacity and metabolic rate in exercising men who received 2 grams of aspartic acid (magnesium and potassium salts) over a 9 week period. A similar failure occurred in a 1983 study from the “International Journal of Sports Medicine” , this study using 6 gram, acute dosages. However, a 1988 study from “Research Quarterly for Exercise and Sport”, found that 10 grams of Aspartic Acid salts effectively increased time to exhaustion (cycling) in male athletes. This study also noted significant decreases in ammonia and lactate, indicating that this was the mechanism of action.
So, while different studies have yielded different results, it does appear that higher doses of Aspartic Acid may convey some anti-fatigue benefits during extended exercise. Unfortunately, Stim-Elite contains nowhere near a high enough dose to convey the above mentioned anti-fatigue benefits, so for now it’s a little unclear why exactly BPI threw Aspartic Acid into the blend.
Caffeine causes an increase in the release of Catecholamines (i.e. Noradrenaline, Adrenaline, Dopamine) which are inherently pro-lipolytic. However, these effects may fade with prolonged use which limits the efficacy of Caffeine as a long-term weight-loss solution. That being said, Caffeine may be at least somewhat synergistic with other stimulants and tends to increase perceived energy, leading to more intense workouts.
GREEN COFFEE BEAN:
A 2010 study from “Food and Chemical Toxicology” noted multiple anti-obesity effects of Chlorogenic Acid administered to mice including increase beta-oxidation. However, Chlorogenic Acid may also have an alternative mechanism of action via inhibition of carbohydrate absorption.
A 2007 study, published in the “Journal of International Medical Research”, found that 12 weeks of Green Coffee (yielding 450-500mg Clorogenic Acid) supplementation resulted in a reduction (6.9%) in glucose absorption in healthy volunteers. Researchers also noted average weight loss of 5.4 kg (almost 12 lbs) over the duration of the study in the group receiving the Green Coffee Extract. These findings conflict with an earlier 2006 study in which Green Coffee Extract (yielding 140mg Chlorogenic Acid) supplementation did not result in weight loss over the same 12 week period. The obvious difference between these two studies is that the dose of the first (positive) study was about 3 times the dose used in the second (negative) study. Finally, a 2012 study found that adults who consumed GCE (containing about 315mg Chlorogenic Acid) daily lost an average of 8kg with the average reduction in body fat being about 4%.
Though GCE has shown mixed results in various studies, efficacy has been demonstrated using higher doses. Unfortunately, Stim-Elite contains an undisclosed amount of Green Coffee Extract that is likely much less than the doses found to be effective for weight-loss.
Raspberry Ketone, a molecular constituent of Raspberries, has become a popular weight-loss additive in dietary supplements. However, the evidence for raspberry ketone as a fat-burning ingredient is extremely limited and there is actually no direct evidence the ingredient is effective in oral, supplemental doses. In vitro studies using very high concentrations have shown positive results, but human studies are non-existent. The only human study that exists grouped RK in with several other popular weight loss ingredients so the effects cannot be attributed to Raspberry Ketone alone. Even in rat studies, RK has failed to show any significant fat-burning effects. At this time there is just no evidence to indicate Raspberry Ketone is an effective fat-burning ingredient at reasonable doses.
The primary active alkaloid of Yohimbe (Pausinystalia Yohimbe) is Yohimbine, which acts as an alpha-2 receptor antagonist, meaning it inhibits the receptor responsible for blocking lipolysis (fat burning). By blocking the action of this receptor Yohimbine essentially allows for more lipolysis to occur. A 2006 study showed that while there were no increases in strength, supplementation induced fat loss in athletes (soccer players). As previously stated, Yohimbine directly acts on alpha-2 receptors, but its fat loss capabilities may also be magnified by its ability to increase the catecholamine neurotransmitters adrenaline and noradrenaline which in turn activate beta-receptors to stimulate lipolysis. However, this increase in catecholamines may fade with prolonged use (more than 2 weeks). That being said, combined with exercise (exercise releases catecholamines itself) or other stimulants (like caffeine), Yohimbine’s fat burning effects can be quite significant.
THE BOTTOM LINE:
Stim Elite actually only contains two stimulants, Caffeine and Yohimbe. Unfortunately, the other ingredients in the formula are either ineffective or, in the case of Green Coffee Extract, under-dosed. Stim-Elite is far from a highly effective fat-burner, although some fat-loss is possible (mostly due to caffeine and yohimbe). At about 85 cents per serving, we can’t recommend Stim Elite as an economical fat-burner, since achieving substantial weight-loss would likely require multiple doses.
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