GAT Nitraflex Review

Nitraflex contains some very familiar pre-workout ingredients listed under their not so familiar chemical names. As if that weren’t confusing enough, GAT has further elected to conceal the levels of those ingredients within one big proprietary blend…

GAT Nitraflex


2-Amino-5-(Carbamoylamino)pentanoic Acid (Citrulline)

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 Mallate 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. Nitraflex contains an unknown quantity of Citrulline, though it is likely in the 1-3 gram range.

(S)-2-Amino-5-Guanidinopentanoic Acid (Arginine)

Arginine is a non-essential amino acid that acts as a precursor to Nitric Oxide. Supplement manufactures claim that, because Arginine is a precursor to Nitric Oxide, supplemental Arginine may boost Nitric Oxide levels, resulting in vasodilation. However, recent studies have found that Arginine isn’t all it’s cracked up to be. The human body is complex and, unfortunately for supplement companies, ingesting a precursor to a substance doesn’t necessarily increase the levels of that substance. A 2012 study, published in “Nutrition and Metabolism”, found that acute (one-time) L-Arginine supplementation with 6 grams did not increase plasma (blood) levels of Nitric Oxide in people with normal Asymmetric Dimethylarginine levels. Asymmetric Dimethylarginine is a compound that is chemically related to Arginine and directly interferes with the production of Nitric Oxide.

Furthermore, recent studies have questioned whether Arginine may in fact be counter-productive during exercise. A 2011, placebo controlled study, found that subjects performed worse after receiving 3700mg of Arginine Alpha-Ketoglutarate prior to resistance training. Due to the size of this study, it cannot be considered conclusive, but it certainly should warrant further studies. While most studies have failed to prove that L-Arginine supplementation increases strength, a 2012 double-blind placebo controlled study, found that supplementation with 6 grams of L-Arginine increased muscle blood volume post-workout, but did not increase intra-workout strength. While this may be disappointing for those looking to increase strength through supplementation, Arginine’s real benefits may lie in post-workout recovery, rather than intra-workout performance. More blood in the muscle’s after a workout means more nutrients to the muscle cells. However, this one study does not offset the mostly negative results of multiple separate studies. The exact amount of Arginine in Nitraflex is unknown, though it doesn’t really matter much since Arginine, at any dose, is unreliable. Given that Arginine and Citrulline have never been shown to be synergistic in any way, it doesn’t make sense to include both of them in the formula. Citrulline is simply a superior way of increasing plasma Arginine, so why not just include more Citrulline? :

(E)-5-(4-Hydroxystyryl)benzene-1,3-Diol (Resveratrol)

Resveratrol has gained massive popularity in recent years as an anti-aging supplement, though there is really no evidence which indicates it can extend the lifespan of humans. That being said, it is a relatively potent antioxidant which has implications for overall cardiovascular health. A 2012 study, published in “The Journal of Physiology”, concluded that Resveratrol was able to improve exercise performance via augmenting fatty acid oxidation in rats. Whether this effect holds true in humans remains unclear.

4-[(E)-2-(3,5-Dimethoxyphenyl)ethenyl]phenol (Pterostilbene)

Pterostilbene is a derivative of Resveratrol which appears considerably more potent with respects to its anti-oxidant properties, though very few studies have been conducted thus far. In the context of a pre-workout, Pterostilbene may be intended to enhance the efficacy of caffeine. PurEnergy is a patented combination of caffeine and Pterostilbene which, according to the manufacturer, is superior in terms of absorption and duration of effects. The only study was conducted by Chromadex, the company that manufactures PurEnergy, but the results do seem to back up the claims. Ultimately, it appears the combination of Caffeine and Pterostilbene may allow for more sustained energy than ordinary caffeine. However, Nitraflex does not contain PurEnergy, it merely contains the two components as separate ingredients, so it’s unclear whether the implications are the same.

3-Aminopropanoic Acid (Beta-Alanine) (As CarnoSyn®)

Beta Alanine is a non-essential amino acid that, along with Histidine, serves as a precursor to the amino acid Carnosine. Carnosine acts a lactic acid buffer, effectively delaying fatigue in the working muscle. Beta Alanine takes time to accumulate, but if taken over a sustained period of time (a few weeks), can be an extremely effective performance enhancing supplement with a strong safety profile. One study in particular that measured the carnosine levels of sprinters found that individuals with higher muscular Carnosine levels exhibited higher power output in the latter half of a 30m sprint (because they had less lactic acid build-up). Multiple studies have confirmed that Beta Alanine supplementation increases muscular Carnosine, which improves physical performance. In particular, a 2012 study published in “Amino Acids” found that subjects who consumed 1.6 or 3.2 grams of Beta Alanine daily experienced significant increases in muscle carnosine in as little as two weeks, with the higher dose achieving a higher concentration of Carnosine. As with the above mentioned ingredients, it remains unclear exactly how much Beta-Alanine is present in the Nitraflex formula. Given its position in the blend (after Resveratrol and Pterostilbene), it’s not likely that there is a truly effective dose.

1,3,7-Trimethyl-1H-Purine-2,6(3H,7H)-Dione (Caffeine)

Caffeine is the most widely consumed psychoactive substance in the world, and is a well-established ergogenic aid. Caffeine consumption causes an increase in Catecholamines (Adrenaline, Noradrenaline, and Dopamine), which tend to increase focus, concentration, and perceived energy while simultaneously promoting fat oxidation. However, this increase in fat-oxidation tends to fade with prolonged use, so it does not appear as though caffeine is a long-term effective fat burner. While caffeine’s weight loss potential is negligible, it increases focus and perceived energy in most people, which generally leads to more intense workouts. Nitraflex contains 325mg of Caffeine per serving, more than enough to provide the average person with a noticeable jolt of perceived energy. It is likely the hefty doses of Caffeine that prompted GAT to recommend starting with half a serving.

2-(Dimethylamino) Ethanol (DMAE)

DMAE is becoming a popular supplement specifically as a nootropic, because it is a cholinergic compound which may enhance certain aspects of cognition via increasing levels of acetylcholine in the brain. Because of this increase in acetylcholine, potential benefits may include increased exercise capacity but there haven’t been enough human studies to be sure. One study done in 1991 showed that a mixture containing DMAE, ginseng, vitamins, and a few minerals “increased the subjects’ work capacity by improving muscular oxygen utilization”. However, the obvious flaw with these findings is that they did not isolate the variable, and therefore can’t say with any certainty which ingredient was truly responsible for the positive results.

2-Acetylamino-3-(4-Hydroxyphenyl)-Propanoic Acid (N-Acetyl L-Tyrosine)

Tyrosine is a non-essential amino acid which serves as a precursor to the neurotransmitters Dopamine, Norepinephrine, and Epinephrine, the three of which are collectively referred to as ‘catecholamines’. A 1981 study found that subjects who consumed 100mg/kg of Tyrosine experienced a significant increase in urinary catecholamine levels, yet supplemental Tyrosine has failed to produce the performance enhancing effects commonly associated with increased release of catecholamines. This is because Tyrosine does not instantly get converted into noradrenaline, dopamine, or adrenaline. It forms a pool, and when there is a deficit of catecholamines, the pool is drawn from to create more. In other words, Tyrosine may restore levels of dopamine, noradrenaline, and adrenaline when necessary, but does not increase them beyond normal levels. So rather than directly improving physical performance, Tyrosine has demonstrated the ability to improve aspects of cognitive function in the presence of an acute stressor (sleep deprivation, exposure to cold, and possibly exercise).

2-Amino-4-(Ethylcarbamoyl) Butyric Acid (Theanine):

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.

Rauwolscine (Rauvolfia Canescens L. [Leaf And Root]):

Rauwolscine (also known as alpha-yohimbine) is what is known as a ‘stereoisomer’ of yohimbine, meaning it is chemically similar in structure. Because of this similarity, Rauwolscine produces similar effects and is also a beta-adrenergic receptor agonist which can induce lipolysis.

Calcium Fructopyranose Borate (CFB):

Calcium Fructopyranose Borate, or CFB, is a combination of Calcium , Fructose, and Boron, that is touted to be a superior delivery form of Boron. Whether this is true or not remains unclear, but as long as it isn’t worse, it doesn’t really matter much. In the context of the Nitraflex formula, Boron is meant to increase (or atleast optimize) Testosterone.

Boron has somewhat of a questionable track record regarding its use as a test-booster. In the early days of bodybuilding, Boron became popular, but then lost popularity (one would think because it doesn’t work). Recently, however, Boron is making a come-back with the same claims attached to it. A 2011 study, published in the “Journal of Trace Minerals in Medicine and Biology”, found that boron supplementation (11.6 mg daily) over a one week period was found to increase testosterone to a statistically significant degree (28%). An earlier study (1993), found that daily supplementation with 2.5 mg of boron over a 7 week period failed to increase testosterone levels. The obvious reason for the discrepancy is that the 2011 study used 4-5 times as much boron as the earlier study. While there does appear to be something here, we would still consider the evidence a bit too inconclusive to be sold on boron as a test booster. However, preliminary evidence suggests high doses (over 10mg) may be effective.


Nitraflex contains nothing new in terms of ingredients. GAT is simply using chemical names, a technique we’ve seen with PharmaFreak as well, to reduce label transparency. The formula contains all the usual pre-workout ingredients such as Citrulline, Beta-Alanine, Arginine, as well as some stimulant compounds (Caffeine, Rauwolscine). We like the inclusion of Theanine, which will help to counteract the jitters associated with excessive caffeine intake, though we can’t be sure if the quantity is truly effective in this case. From an ingredient standpoint, the formula is a solid one, but given the extreme lack of transparency, we can’t be sure that Nitraflex contains effective levels of certain ingredients (particularly Citrulline).

Still not sure which pre-workout is right for you? Check out our Top 10 Pre-Workout Supplements List!

Supplement Facts

  1. Bendahan, D., et al. “Citrulline/malate promotes aerobic energy production in human exercising muscle.” British journal of sports medicine 36.4 (2002): 282-289.
  2. 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.
  3. Giannesini, Benoît, et al. “Citrulline malate supplementation increases muscle efficiency in rat skeletal muscle.” European journal of pharmacology 667.1 (2011): 100-104.
  4. 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.
  5. Arciero, PAUL J., et al. “Effects of caffeine ingestion on NE kinetics, fat oxidation, and energy expenditure in younger and older men.” American Journal of Physiology-Endocrinology And Metabolism 268.6 (1995): E1192-E1198.
  6. Astrup, A., et al. “Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers.” The American journal of clinical nutrition 51.5 (1990): 759-767.
  7. Zhang Alvares, Thiago S., et al. “L-Arginine as a Potential Ergogenic Aidin Healthy Subjects.” Sports Medicine 41.3 (2011): 233-248.
  8. Dolinsky, Vernon W., et al. “Improvements in skeletal muscle strength and cardiac function induced by resveratrol contribute to enhanced exercise performance in rats.” The Journal of Physiology (2012): jphysiol-2012.
  9. Ferrando, A. A., and N. R. Green. “The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders.”International journal of sport nutrition 3.2 (1993): 140.
  10. Nielsen, Forrest H., et al. “Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women.” The FASEB journal 1.5 (1987): 394-397.
  11. Zhang Wax, Benjamin, et al. “Acute L-arginine alpha ketoglutarate supplementation fails to improve muscular performance in resistance trained and untrained men.”Journal of the International Society of Sports Nutrition 9.1 (2012): 17.
  12. Sale, Craig, Bryan Saunders, and Roger C. Harris. “Effect of beta-alanine supplementation on muscle carnosine concentrations and exercise performance.” Amino acids 39.2 (2010): 321-333.
  13. Stellingwerff, Trent, et al. “Effect of two β-alanine dosing protocols on muscle carnosine synthesis and washout.” Amino Acids 42.6 (2012): 2461-2472.
  14. Wilson, Jacob M., et al. “Beta-alanine supplementation improves aerobic and anaerobic indices of performance.” Strength & Conditioning Journal 32.1 (2010): 71-78.
  15. Sutton, Erin E., M. R. Coill, and Patricia A. Deuster. “Ingestion of tyrosine: effects on endurance, muscle strength, and anaerobic performance.” International journal of sport nutrition and exercise metabolism 15.2 (2005): 173.
  16. Costill, D. L., Gl P. Dalsky, and W. J. Fink. “Effects of caffeine ingestion on metabolism and exercise performance.” Medicine and science in sports 10.3 (1977): 155-158.
  17. Graham, T. E., and L. L. Spriet. “Metabolic, catecholamine, and exercise performance responses to various doses of caffeine.” Journal of Applied Physiology 78.3 (1995): 867-874.
  18. Graham, Terry E. “Caffeine and exercise.” Sports medicine 31.11 (2001): 785-807.
  19. Suzuki, Yasuhiro, Osamu Ito, Naoki Mukai, Hideyuki Takahashi, and Kaoru Takamatsu. “High Level of Skeletal Muscle Carnosine Contributes to the Latter Half of Exercise Performance during 30-s Maximal Cycle Ergometer Sprinting.” The Japanese Journal of Physiology 52.2 (2002): 199-205.
  20. Hickner, Robert C., Charles J. Tanner, Chris A. Evans, Paige D. Clark, Amy Haddock, Chris Fortune, Heather Geddis, William Waugh, and Michael Mccammon. “L-Citrulline Reduces Time to Exhaustion and Insulin Response to a Graded Exercise Test.” Medicine & Science in Sports & Exercise 38.4 (2006): 660-66.
  21. Agharanya, Julius C., Raphael Alonso, and Richard J. Wurtman. “Changes in catecholamine excretion after short-term tyrosine ingestion in normally fed human subjects.” The American journal of clinical nutrition 34.1 (1981): 82-87.
  22. Shurtleff, David, et al. “Tyrosine reverses a cold-induced working memory deficit in humans.” Pharmacology Biochemistry and Behavior 47.4 (1994): 935-941.
  23. Fernstrom, John D., and Madelyn H. Fernstrom. “Tyrosine, phenylalanine, and catecholamine synthesis and function in the brain.” The Journal of nutrition137.6 (2007): 1539S-1547S.
  24. Yeghiayan, Sylva K., et al. “Tyrosine improves behavioral and neurochemical deficits caused by cold exposure.” Physiology & behavior 72.3 (2001): 311-316.
  25. Banderet, Louis E., and Harris R. Lieberman. “Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humans.” Brain research bulletin 22.4 (1989): 759-762.
  26. Meeusen, Romain, Phil Watson, and Jiri Dvorak. “The brain and fatigue: New opportunities for nutritional interventions?.” Journal of sports sciences 24.07 (2006): 773-782.
  27. Kobayashi, Kanari, Yukiko Nagato, Nobuyuki Aoi, Lekh Raj Juneja, Mujo Kim, Takehiko Yamamoto, and Sukeo Sugimoto. “Effects of L-Theanine on the Release of .ALPHA.-Brain Waves in Human Volunteers.” Journal of the Agricultural Chemical Society of Japan 72.2 (1998): 153-57.
  28. Kimura, Kenta, Makoto Ozeki, Lekh Raj Juneja, and Hideki Ohira. “L-Theanine Reduces Psychological and Physiological Stress Responses.” Biological Psychology 74.1 (2007): 39-45. exists to educate the supplement community and seperate the science from the hype.

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