Agmatine: common claims examined

Agmatine made its way into sports nutrition as a “pump ingredient” in the late 2000s, and since then a lot of marketing claims have accumulated around it. Some of them are based on real laboratory data, but the conclusions from these data are often distorted. The editors have broken down the most common myths and compared them with what research actually shows.

What is agmatine and where do the myths come from

Agmatine is a decarboxylation product of the amino acid L-arginine, i.e. arginine, from which the carboxyl group has been removed by the enzyme arginine decarboxylase. The substance was discovered at the beginning of the 20th century, but the real interest in it arose in 1994, when the Li and Reis group described agmatine as an endogenous brain substance that binds to imidazoline and alpha-2-adrenergic receptors.

In mammalian tissues, agmatine is present in very low concentrations and is broken down by the enzyme agmatinase. With food, we get a certain amount of agmatine from fermented foods - beer, wine, cheese, fermented vegetables, as well as fish, where it is formed under the action of bacteria. There is little well-measured data on typical dietary intake.

The range of targets of agmatine in preclinical models is very wide: imidazoline receptors, alpha-2-adrenoceptors, NMDA-receptors of glutamate, several isoforms of nitric oxide synthase, ion channels. It is this "omnivory" that has become the basis for myths: almost any marketing claim can be supported by a reference to some experimental work on cells or rodents.

The problem is that the effect in a test tube or in a rat after an intra-abdominal injection is not equal to the effect in a person after taking a capsule orally. The number of high-quality clinical studies of agmatine in humans is counted in units, and there are practically no studies specifically on athletes. Therefore, below we separately mark where the human data ends and extrapolation begins.

For orientation, here is a brief summary: which claims are most often found on labels and product descriptions, and how we evaluate them against the available evidence base.

The myth of the "powerful nitric oxide donor"

The most common claim is that agmatine supposedly "enhances NO" and provides a pronounced filling of muscles with blood during training. The marketing logic is simple: agmatine is derived from arginine, arginine is a substrate for nitric oxide synthesis, so agmatine should also increase NO. In fact, biochemistry works differently.

Arginine in the body can go in several ways: through nitric oxide synthase (NOS) to NO and citrulline, through arginase to ornithine and urea, through arginine decarboxylase to agmatine. Agmatine is an end product of a separate pathway, not an "accelerator" of the NO pathway. Moreover, in experimental works, agmatine is described as an inhibitor of some isoforms of NOS, in particular inducible and neuronal.

A well-known argument by supporters is the effect of agmatine on endothelial NOS in some vascular models and animal vasodilation. Such data do exist, but they are obtained by direct administration of the substance, in doses and concentrations that cannot be reproduced by oral administration of several hundred milligrams. The editors did not find any studies that measured blood flow in the working muscles of a person after agmatine.

The "pump" feeling from pre-workout complexes with agmatine is usually explained by other components: citrulline, nitrates, caffeine, carbohydrates, as well as the type of training itself with a high number of repetitions. It is impossible to single out the contribution of agmatine in such mixtures.

Therefore, the statement about agmatine as a "donor of nitric oxide" is biochemically incorrect, and the statement about increased blood flow in human muscles is not confirmed. If the goal is vasodilation, there are ingredients with a much better evidence base for it, primarily citrulline and dietary nitrates.

Myth about anabolic and hormonal effect

In some product descriptions, agmatine is presented as a substance that stimulates the release of growth hormone, luteinizing hormone, and even testosterone. The source of such statements are separate experiments on animals and on isolated tissues of the hypothalamus and pituitary gland, where agmatine affected the secretion of hormones.

However, the effect on hormone secretion in isolated tissue is a very distant link from a real increase in muscle mass. Even for stimuli that increase growth hormone in humans (such as intense exercise or sleep), short-term spikes in growth hormone do not necessarily translate into additional muscle gain.

Controlled studies comparing agmatine with placebo on strength, muscle mass, or testosterone levels in trained individuals have not been published at the time of writing. That is, claims about "anabolic agmatine" do not have even weak clinical evidence.

It is also worth remembering that the effect on alpha-2-adrenoceptors can theoretically have the opposite consequences — for example, reduce sympathetic activity and blood pressure. For an athlete, this is not necessarily a desirable effect before intensive training.

The editor's conclusion here is simple: agmatine is neither an anabolic nor a "testosterone booster." Taking it for this purpose has no scientific basis, and the expectations created by advertising will most likely not come true.

The myth of a "natural and therefore safe" substance

The argument “agmatine is in our brains and in food, so it is safe” sounds convincing, but contains a logical fallacy. The endogenous nature of the substance does not guarantee the safety of taking it in doses that are tens or hundreds of times higher than the natural intake. This rule applies to hormones, vitamins, and amino acids.

The study of Keynan et al. (2010) in patients with radiculopathy associated with intervertebral disc herniation provides the most safety data. Participants received agmatine sulfate at a dose of 2.67 g per day for 14 days. The authors noted no serious adverse reactions, and tolerability was comparable to placebo; some participants reported mild gastrointestinal symptoms.

There is also a clinical case report in which one person took high doses of agmatine for five years with no detectable laboratory abnormalities (Gilad and Gilad, 2014). Such observations are interesting, but a single case cannot replace systematic safety studies on large groups.

Several questions remain unanswered, which the editors consider important:

• effect of long-term intake on blood pressure and heart rate, taking into account the effect on alpha-2 and imidazoline receptors;
• interaction with antihypertensive drugs, antidepressants, painkillers and agents affecting NMDA receptors;
• safety during pregnancy, breastfeeding and in adolescents - such data are not available;
• quality of raw materials: the content of the declared substance in additives is independently checked infrequently.

So, the correct formulation is: agmatine was well tolerated in short-term studies, but little is known about long-term safety, interactions, and effects in specific populations. People taking blood pressure medications or psychotropic medications should discuss the supplement with their doctor.

Myths about pain relief, mood and "nootropic" action

The most interesting data on agmatine is not in sports, but in neurology. In the previously mentioned study by Keynan (2010), in the randomized placebo-controlled part, taking agmatine was accompanied by a greater reduction in pain and improvement in quality of life than placebo. However, this is one study with a small sample and a specific group of patients.

This often leads to the false conclusion that agmatine is a universal "athlete pain reliever" that helps with injuries and muscle pain after training. Neuropathic pain with nerve root compression and post-exercise muscle soreness have different mechanisms, so it is incorrect to transfer the results from one condition to another.

A similar situation with mood. In rodents, agmatine has shown antidepressant-like effects in behavioral tests, and a pilot study by Shopsin (2013) described improvements in several depressed patients. However, in pilot studies without a control group, it is impossible to distinguish the effect of the substance from the placebo effect and the natural course of the disease.

Regarding "nootropic" properties - improving memory, concentration, reaction speed - the editors did not find controlled studies in healthy people. The claim that agmatine "improves training focus" is based on extrapolation of data on glutamate receptors in animal models.

A review by Piletz et al. (2013) details the potential clinical applications of agmatine and explicitly states that most of them require confirmation in randomized trials. This is exactly how these directions should be perceived: as hypotheses, and not as proven properties of the supplement.

Editorial conclusions

Agmatine is a biologically active molecule with interesting pharmacology, but most of the claims it is marketed to athletes are not supported in human studies. It is not a donor of nitric oxide, its effect on hormones or muscle mass has not been proven.

Possible analgesia for neuropathic pain remains the most reasonable direction, but even here the evidence base is limited to one randomized study. For sports purposes, these data mean almost nothing.

Short-term use in studies was well tolerated, but long-term safety and drug interactions are poorly studied. The natural origin of the substance does not exempt from caution.

If you are interested in the topic, the editors recommend reading our articles on citrulline malate as the ingredient with the best evidence base for blood flow, dietary nitrates and beetroot juice, and our review of pre-workout ingredients.

References

1. Li G, Regunathan S, Barrow CJ, Eshraghi J, Cooper R, Reis DJ. Agmatine: an endogenous clonidine-displacing substance in the brain. Science. 1994;263(5149):966–969.
2. Piletz JE, Aricioglu F, Cheng JT, et al. Agmatine: clinical applications after 100 years in translation. Drug Discov Today. 2013;18(17–18):880–893.
3. Keynan O, Mirovsky Y, Dekel S, Gilad VH, Gilad GM. Safety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial. Pain Med. 2010;11(3):356–368.
4. Gilad GM, Gilad VH. Long-term (5 years), high daily dosage of dietary agmatine — evidence of safety: a case report. J Med Food. 2014;17(11):1256–1259.
5. Shopsin B. The clinical antidepressant effect of exogenous agmatine is not reversed by parachlorophenylalanine: a pilot study. Acta Neuropsychiatr. 2013;25(2):113–118.
6. Halaris A, Plietz J. Agmatine: metabolic pathway and spectrum of activity in brain. CNS Drugs. 2007;21(11):885–900.