Rush is a pre-workout released under the EPIQ brand which is under the Iovate Health Sciences umbrella (along with MuscleTech and Hydroxycut). It contains a variety of standard pre-workout ingredients but the emphasis appears to be on Nitrate content…[Skip to the Bottom Line]
Citrulline Nitrate simply refers to Citrulline fused with Nitric Acid. By combining these two compounds, Citrulline Nitrate is able to convey both the benefits of Citrulline and the benefits of Nitrate.
A common claim associated with Nitrate-fused compounds is that the Nitrate portion enhances absorption because Nitrates tend to be highly absorbable (98-100%). However, since there are no studies (not even in animals) assessing the absorption of other compounds fused with Nitrate, we can only assume the benefits of such compounds as Citrulline Nitrate are equivalent to the same amount of those substances on their own.
Citrulline is a precursor to the amino acid Arginine, which is a precursor to Nitric Oxide (NO). A 2009 study, published in the “Journal of Free Radical Research”, found that 6 grams of Citrulline Malate given to male cyclists before a race increased “plasma Arginine availability for NO synthesis and PMNs priming for oxidative burst without oxidative damage”.
You may be wondering: How can Citrulline be more effective at increasing Arginine than Arginine itself? The problem with supplemental Arginine is that it is metabolized in the intestines and liver into other substances such as Ornithine and Urea. The intestines and liver contain relatively high levels of Arginase, the enzyme that converts Arginine to Ornithine and Urea. As a result, very little goes on to be involved with the synthesis of NO because it is being diverted for other purposes. Citrulline, on the other hand, is able to bypass the liver and is metabolized into Arginine elsewhere, where not as much Arginase is present. Thus, more of the Arginine is able to convert into NO.
A 2002 study, published in the “British Journal of Sports Medicine” found that Citrulline supplementation (6g/day for 15 days) significantly increased ATP production during exercise in healthy adult males. A 2011 study, the subjects of which were rats, found that supplemental Citrulline increased muscular contraction efficiency (less ATP was required for the same amount of power), in-line with the findings of the above-mentioned human study. Unfortunately, Rush contains just 450mg of Citrulline, far below the amounts shown to convey the above mentioned benefit.
A 2012 study, published in “Journal of the Academy of Nutrition and Dietetics”, found that increased dietary nitrate intake improved running performance in healthy adults. A 2013 study, published in the “European Journal of Applied Physiology”, found that Nitrate supplementation effectively elevated plasma Nitrate levels which translated to improved performance during high-intensity exercise in athletes. A 2013 Meta-Analysis, which looked specifically at 17 separate studies using doses of 300-600mg Nitrate from various sources, concluded that supplementation is associated with a moderate improvement in time to exhaustion at a given work load.
EPIQ Rush contains 156mg of Nitrate per serving, so it is likely that two servings must be consumed to convey the benefits generally associated with Nitrate supplementation.
Contrary to popular belief, Taurine is not a stimulant but rather an an amino acid with anti-oxidant properties. In a 2011 study, Taurine was shown to significantly decrease oxidative stress in skeletal muscle following exercise. Prior to that, a 2004 study 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 noted a 1.7% improvement in 3k-time trial of runners after supplementing with Taurine, but noted that more research would be required to determine the exact mechanism of action.
It’s unfortunate that Taurine has developed a sort of stigma because of its inclusion in energy drinks. While Taurine does not provide “energy” in the way that caffeine does, several studies have shown its effectiveness as an antioxidant with workout-enhancing properties, and while the exact mechanism of action remains unknown, it appears likely that Taurine may improve exercise performance by reducing some of the cellular oxidative damage that generally leads to fatigue. The usual dose of Taurine used for performance enhancement is about 1 gram though Rush contains much less (likely around 100-200mg).
Aspartic Acid has been touted as a performance enhancer for decades, but unfortunately, more and more studies have shown that it is far from a miracle. Preliminary evidence suggested that aspartic acid may increase the rate of ammonia removal from the blood during exercise which may allow athletes to go on for longer. However, a 1983 study, published in the “International Journal of Sports Medicine”, found that Aspartic Acid has absolutely no effect on parameters of exercise performance in men.
Cordyceps is a mushroom which has a long history of use in Traditional Chinese Medicine for a variety purposes. In the context of the Rush formula, Cordyceps is meant to reduce fatigue. Though human trials are virtually non-existent with regards to this claim, a 2003 study found that Cordyceps increased time to fatigue in swimming rats.
GREEN TEA EXTRACT:
Multiple studies have confirmed Green Tea Extract appears to be able to induce fat-loss. Although this effect was originally thought to be related to caffeine content, more recent research has pointed to a green tea catechin known as Epigallocatechin gallate as the compound primarily responsible for these effects.
Epigallocatechin gallate (EGCG) is an antioxidant found in green tea, and is a member of the group of antioxidants known as catechins. In addition to these antioxidant properties, EGCG has demonstrated the ability to induce fat–loss when combined with caffeine, more than just caffeine alone. EGCG works synergistically with caffeine in regards to its effect on noradrenaline. Caffeine boosts noradrenaline while EGCG inhibits catechol-o-methyl transferase (COMT), the enzyme responsible for the degredation of noradrenaline. So, caffeine increases noradrenaline, while EGCG prevents its breakdown, the net effect of which is increased levels of noradrenaline (which induces the breakdown of fat).
Although caffeine is generally used along-side EGCG to induce catecholamine release, EGCG can be synergistic with endogenously produced catcholamines (from exercise) as well as other fat burning compounds that release catecholamines.
Though EGCG does have clear fat-loss implications, COMT inhibition may ultimately improve exercise in a synergistic manner with caffeine. When looked at from this angle, fat-loss is essentially a side-effect whereas increased energy and focus would be the primary effect. Generally, between 400-500mg of EGCG must be consumed daily to result in fat-loss. However, Rush contains only 25mg of EGCG per 100mg serving of Green Tea Extract. At this dose, the COMT inhibition effects of Green Tea Extract are likely negligible.
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. Even in rat studies, RK fail to show any significant fat-burning effects. The overall consensus of the scientific community is that raspberry ketone are nothing more than industry hype.
GREEN COFFEE EXTRACT:
A 2010 study from “Food and Chemical Toxicology” found noted multiple anti-obesity effects of Chlorogenic Acid administered to mice including increase beta-oxidations. 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. 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. That being said, Rush contains nowhere near an effective dose of Green Coffee Extract in terms of Chlorogenic Acid content.
Caffeine is a well-established ergogenic aid/cognitive enhancer and is the most commonly consumed psychoactive stimulant in the world. Caffeine causes an increase in catecholamines, resulting in increased alertness, focus, and perceived energy. These neurotransmitters tend to be pro-lipolytic, so it is commonly assumed that caffeine is a fat-burner. While the mechanisms of caffeine are certainly pro-fat-burner, the effects tend to fade with prolonged use, rendering caffeine ineffective as a long-term weight loss solution. However, it is a highly effective ergogenic aid and will certainly enhance performance when taken pre-workout. Rush contains 138mg of Caffeine.
Theanine is a great additive to any pre-workout because of its ability to counter the negative effects of caffeine. Theanine is commonly found in Green Tea and is generally believed to be the agent in the tea that promotes relaxation and counteracts the caffeine that is also present in Green Tea. Multiple studies have confirmed Theanine’s ability to promote “alert relaxation”. For this reason, it is a perfect complement for high levels of caffeine. While we don’t know the exact amount of Theanine present in the Rush formula, we estimate it is around 25mg.
RAW COCONUT WATER:
Coconut Water has become quite popular in the beverage (specifically sports drink) industry because of its natural electrolyte profile. Yes, electrolytes are incredibly important for proper inter-cellular communication, and the need for electrolytes may increase with prolonged exercise. However, it is unclear whether there is any benefit of the “natural” electrolytes found in Coconut Water beyond those conveyed through synthetic electrolyte supplementation. There is likely no difference, but Coconut Water does provide an all-in-one source of electrolytes so it shouldn’t be viewed as a negative either.
Glycerophosphatidylcholine aka Alpha GPC is a precursor to the neurotransmitter acetylcholine. Recently, it has gained a lot of attention in the bodybuilding/weight lifting community because its alleged ability to boost HGH (Human Growth Hormone) secretion with just a single dose. Indeed one study found that after ingesting a dose of 1000mg of Alpha GPC, HGH levels in the blood were significantly higher than the placebo group. In addition, it was noted that supplementation also resulted in increased “hepatic fat oxidation” (in the liver). A 2008 study, published in the “Journal of the International Society of Sports Nutrition”, found that oral supplementation of 600mg of Alpha GPC increased Power Output by an average of 14% in resistance trained males.
Alpha GPC is widely considered the most bioavailable form of choline, although studies comparing the bioavailability of various forms are scarce. Over time, Alpha GPC may increase the levels of acetylcholine in the brain. Increased acetylcholine levels are associated with better concentration, memory, and reaction time. That being said, the dose of Alpha GPC present in the Rush formula is nowhere near an effective dose for increasing Acetylcholine to any significant degree. Given its position on the label, we estimate there is roughly 5-10mg of Alpha GPC, far short of the 600mg demonstrated to increase power output.
THE BOTTOM LINE:
While the ingredient profile of Rush is a solid one, the formula is seriously under-dosed. While adequate doses of Nitrates and Caffeine could possibly be obtained with just 2 servings, several other ingredients are in such small quantities that users could not realistically consume enough servings at once to convey the benefits of these ingredients. At a price of 75 cents per serving, Rush seems appropriately priced, but when taking into the account the less than optimal doses of each individual ingredient, it is actually quite expensive. Ultimately, we cannot recommend this formula for either pre-workout energy or as a thermogenic.
- Ziegenfuss, T. Landis, J. Hofheins, J. “Acute supplementation with alpha-glycerylphosphorylcholine augments growth hormone response to, and peak force production during, resistance exercise”Journal of the International Society of Sports Nutrition 2008, 5(Suppl 1):P15
- Kawamura, Takashi, et al. “Glycerophosphocholine enhances growth hormone secretion and fat oxidation in young adults.” Nutrition 28.11 (2012): 1122-1126.
- Maughan, R. J., and D. J. M. Sadler. “The effects of oral administration of salts of aspartic acid on the metabolic response to prolonged exhausting exercise in man.” International journal of sports medicine 4.02 (1983): 119-123.
- Sureda, Antoni, et al. “Effects of L-citrulline oral supplementation on polymorphonuclear neutrophils oxidative burst and nitric oxide production after exercise.” Free radical research 43.9 (2009): 828-835.
- Bendahan, D., et al. “Citrulline/malate promotes aerobic energy production in human exercising muscle.” British journal of sports medicine 36.4 (2002): 282-289.
- Gleeson, M., and N. C. Bishop. “Elite athlete immunology: importance of nutrition.” International journal of sports medicine 21.Sup. 1 (2000): 44-50.
- Jones, Andrew M. “Nitrate Supplementation and Exercise Performance.”
- Silva, Luciano A., et al. “Taurine supplementation decreases oxidative stress in skeletal muscle after eccentric exercise.” Cell biochemistry and function 29.1 (2011): 43-49.
- Zhang, M., et al. “Role of taurine supplementation to prevent exercise-induced oxidative stress in healthy young men.” Amino acids 26.2 (2004): 203-207.
- Bailey, Stephen J., et al. “Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans.” Journal of Applied Physiology 107.4 (2009): 1144-1155.
- Lansley, Katherine E., et al. “Acute dietary nitrate supplementation improves cycling time trial performance.” Med Sci Sports Exerc 43.6 (2011): 1125-1131
- Koh, Jong-Ho, et al. “Antifatigue and antistress effect of the hot-water fraction from mycelia of Cordyceps sinensis.” Biological and Pharmaceutical Bulletin26.5 (2003): 691-694
- Saffari, Yasi, and S. M. Sadrzadeh. “Green tea metabolite EGCG protects membranes against oxidative damage in vitro.” Life sciences 74.12 (2004): 1513-1518.
- Hill, Alison M., et al. “Can EGCG reduce abdominal fat in obese subjects?.”Journal of the American College of Nutrition 26.4 (2007): 396S-402S.
- Vinson, Joe A., Bryan R. Burnham, and Mysore V. Nagendran. “Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects.”Diabetes, metabolic syndrome and obesity: targets and therapy 5 (2012): 21.
- Dellalibera, S. S. Ą., B. Lemaire, and S. Lafay. “„Svetol*, green coffee extract, induces weight loss and increases the lean to fat mass ratio in volunteers with overweight problem.”.” Phytotherapie 4.4 (2006): 194-197.
- Ho, Lap, et al. “Dietary supplementation with decaffeinated green coffee improves diet-induced insulin resistance and brain energy metabolism in mice.”Nutritional neuroscience 15.1 (2012): 37-45.
- Thielecke, Frank, et al. “Epigallocatechin-3-gallate and postprandial fat oxidation in overweight/obese male volunteers: a pilot study.” European journal of clinical nutrition 64.7 (2010): 704-713.
- Lu, Hong, Xiaofeng Meng, and Chung S. Yang. “Enzymology of methylation of tea catechins and inhibition of catechol-O-methyltransferase by (−)-epigallocatechin gallate.” Drug metabolism and disposition 31.5 (2003): 572-579.
- Keränen, Tapani, et al. “Inhibition of soluble catechol-O-methyltransferase and single-dose pharmacokinetics after oral and intravenous administration of entacapone.” European journal of clinical pharmacology 46.2 (1994): 151-157.
- Brown, A. L., et al. “Health effects of green tea catechins in overweight and obese men: a randomised controlled cross-over trial.” British Journal of Nutrition106.12 (2011): 1880-1889.
- Wang, Lili, Xianjun Meng, and Fengqing Zhang. “Raspberry ketone protects rats fed high-fat diets against nonalcoholic steatohepatitis.” Journal of medicinal food 15.5 (2012): 495-503.
- Park, Kyoung Sik. “Raspberry ketone increases both lipolysis and fatty acid oxidation in 3T3-L1 adipocytes.” Planta medica 76.15 (2010): 1654.
- Morimoto, Chie, et al. “Anti-obese action of raspberry ketone.” Life sciences77.2 (2005): 194-204.