MusclePharm Iron Pump Review

Iron Pump

Iron Pump is a pre-workout released under the Arnold Series brand by MusclePharm. Although it contains Caffeine, the focus is clearly on the pump aspect…


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Iron Pump is a pre-workout released under the Arnold Series brand by MusclePharm. Although it contains Caffeine, the focus is clearly on the pump aspect…[Skip to the Bottom Line]


Argine Nitrate is simply L-Arginine fused with Nitrate, conveying the benefits of both compounds (to some degree). 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, 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.

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 strength). This may be disappointing for those looking to increase strength through supplementation, but 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 offset the mostly negative results of multiple separate studies.

There is no evidence indicating that Arginine-Nitrate is, in any way, more bioavailable than standard L-Arginine, but given that Nitrate supplementation is actually able to effective enhance performance, the combination may actually be more beneficial than the same dose of L-Arginine alone.


As in our review of Assault, the reason for the inclusion of Glycine is a bit unclear, though MusclePharm states it is because it is the simplest amino acid, “involved in the formation of proteins, peptides, glycogen, and ATP”. While this may be true, there is absolutely no evidence to suggest that Glycine supplementation has any sort of performance enhancement effect in humans or that it effectively restores ATP.


Agmatine remains very under-researched, despite possessing a variety of health/performance implications. Recently, Agmatine has become quite pervasive in pre-workout supplements because of its alleged ability to regulate Nitric Oxide Synthase (NOS), an enzyme that catalyzes the production of NO from Arginine, and either elevate or reduce its presence, depending on the type of NOS. NOS is a widely misunderstood enzyme, mostly due to supplement companies not properly explaining its function and how that function relates to physical performance. It is largely thought that NOS is the enzyme that “breaks down” NO, when it is actually the enzyme that catalyzes the production of NO from Arginine in the first place.

Nitric Oxide generally has a positive connotation in the bodybuilding/athletic community because it is associated with vasodilation, which clearly has performance/health benefits. However, this beneficial effect of NO only pertains to NO in the blood vessels. Elsewhere in the body (like the brain) NO can inflict damage and actually be quite harmful. So ideally, what we really are after is a way to reduce NO in the areas of the body where it can cause harm, while increasing it in blood vessels where it can beneficially influence physical performance.

It’s important to understand that there are several types of NOS, all which are required for the production of NO. Inducible NOS (iNOS) and Neuronal NOS (nNOS) are considered harmful because they elevate NO in immune cells (causing inflammation) and the brain (causing neuronal damage), while Endothelial NOS (eNOS) is considered beneficial as this is the kind which increases Nitric Oxide in the blood vessels, resulting in vasodilation. Agmatine has been demonstrated to up-regulate eNOS (the “good” NOS) while inhibiting the other NOS enzymes (the “bad” NOS). However, as mentioned above, Agmatine remains under-researched because it is a relatively new entrant in the supplement industry. Currently, most of the research has been done in vitro, with absolutely no studies regarding the potential physical performance benefits of Agmatine in humans. Because of the lack of human studies, no optimal dose has been established for Agmatine, though average doses in pre-workout formulas are 500-1000mg.


The active compound in Beet Root is Nitrate, which converts to Nitric Oxide in the body, and thus is said to convey performance benefits. A 2012 study, published in “Journal of the Academy of Nutrition and Dietetics”, found that increased dietary nitrate intake (in the form of Nitrate-rich whole Beet Root) improved running performance in healthy adults. A 2013 study, published in the “European Journal of Applied Physiology”, found that Nitrate supplementation (from Beet Root juice) 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. It’s tough to say exactly how much Nitrate is present in the Iron Pump formula, because we don’t even know how much Beet Root in total there is, let alone what percentage of that is Nitrate. However, given that there is additional Nitrate in the form of Arginine Nitrate, it is certainly possible that Iron Pump contains an effective dose of Nitrates.


Ornithine is an amino acid used alongside Arginine and Citrulline in the Urea Cycle, the process by which Ammonia is metabolized into the harmless substance Urea. Prolonged exercise generally brings about increases in Ammonia, which causes fatigue in the working muscle after enough has built up. As evidenced in a 2010 study published in the European Journal of Clinical Nutrition, supplemental Ornithine, at a dose of 100mg/kg, has failed to influence fatigue in short duration exercise. However, a 2008 study from “Nutrition Research” noted a significant reduction in fatigue during prolonged exercise in healthy volunteers who consumed 2g Ornithine daily for 6 days and 6g prior to testing. Unfortunately, because of the structure of this study, it is unclear whether Ornithine requires “build-up time” or if acute supplementation is effective. Either way, it appears Ornithine will only be noticeably effective during prolonged exercise, when Ammonia would usually cause fatigue. That being said, Iron Pump contains nowhere near the 2-6g range that proved effective in the above mentioned study, and for that reason it’s difficult to say just how effective it is in the context of this particular formula.


Crataegus pinnatifida, also known as Chinese Hawthorn, is a berry which has traditionally (but not clinically) been used as a heart health agent. Unfortunately, most of these claims are without merit and unsubstantiated by what little research there is. Extracts from Chinese Hawthorn have demonstrated some slight-moderate anti-inflammatory properties in vitro, and these properties have been noted in rats as well (though with less potency than the reference drug used). In all honesty, we’re not exactly clear on why MusclePharm chose to include Chinese Hawthorne in the Iron Pump blend, and the company makes no mention of it in any of the product literature.


Choline, once inside the body, is converted into the neurotransmitter acetylcholine which is associated with many functions including (but not limited to) memory, attention, and muscle control. Acetylcholine is the neurotransmitter most closely associated with the “mind-muscle connection” (although this may be something of an over-simplification), and therefore of much interest to athletes and bodybuilders alike. While certain forms of choline may be associated with increased muscular power output (namely Alpha GPC), Choline Bitartrate is generally considered the least bioavailable choline source, though oral doses of 1000-2000mg have still been shown to increase serum choline levels significantly.

Aside from potentially increasing Acetylcholine, Choline Bitartrate may have more direct implications with regards to performance enhancement. A 2012 study published in the “British Journal of Nutrition” found that 1 gram of Choline Bitartrate was able to significantly increase, not only plasma choline levels, but also plasma Betaine levels. Betaine itself is commonly included in pre-workout formulas as it has been shown, in some cases, to increase power output significantly. While Choline Bitartrate has not been studies in regards to performance enhancement, it is just as effective at increasing Betaine as supplemental Betaine, meaning it may very well convey the same performance enhancement benefits at a given dose. An effective dose would be anywhere from 1.25-2.5g, and while it isn’t clear exactly how much Choline Iron Pump contains, it is possible that the amount is towards the lower end of the effective range (based on a 2051mg blend).


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).


Most people are aware that Caffeine is a psycho active stimulant, capable of increasing “energy”, though few understand how it works. Caffeine causes an increase in catecholamine neurotransmitters (noradrenaline, dopamine, etc.), resulting in a state of increased alertness, focus, and perceived energy. It has been studied extensively as an ergogenic aid, and is extremely effective in most people (who haven’t built up a tolerance). Unfortunately, the effects of Caffeine tend to fade somewhat with prolonged use, so we generally recommend those looking to gain the most out of their Caffeine-containing pre-workout should limit their additional Caffeine intake. It’s unclear exactly how much Caffeine is in the Iron Pump formula.


Vinpocetine is an effective vasodilator which has the ability to increase cerebral blood flow (and thus slightly more oxygenation). As a vasodilator, it stands to reason that Vinpocetine also enhances the “pump” dimension of exercise, though it has not been directly tested in humans with regards to performance enhancement. Fortunately, very low doses (10-40mg) of Vinpocetine are all it takes to convey the benefits, so it is likely that Iron Pump contains an effective dose.


Iron Pump is certainly a “pump” based pre-workout, given that the only stimulant in the blend is Caffeine, and the rest of the ingredients are geared toward more physical performance enhancement. The formula is fairly effective in this regards, and while we don’t know the exact doses of any one ingredients, with the exception of Ornithine there is no obvious flaw in terms of dosage. Iron Pump is certainly not for those who seek intense mental stimulation, although depending on Caffeine tolerance it might serve that purpose in certain individuals. At around 70 cents per serving, Iron Pump is priced about average and may be worth a shot for the more pump-oriented lifter.

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