Arginine is sold without a prescription and is found in ordinary food, so few people think about contraindications. However, for several groups of people, the supplement may be not only useless, but also dangerous. The editors have collected situations in which it is better to refuse arginine or take it only after consulting a doctor.
Cardiovascular diseases
The most important contraindication concerns people who have suffered a myocardial infarction. In the randomized, placebo-controlled VINTAGE MI trial (Schulman et al., 2006), post-infarction patients received arginine or placebo for six months. Arginine did not improve either vascular stiffness or ejection fraction.
Moreover, there were more deaths in the arginine group than in the placebo group, and the study was stopped early for safety reasons. The number of events was small, so it is impossible to prove a causal relationship. However, the authors expressly recommended not to prescribe arginine to patients after a heart attack.
Caution is required in other forms of coronary heart disease, heart failure and rhythm disorders. Although arginine has improved endothelial function in such patients in some small studies, the decision to use arginine should be made by the cardiologist taking into account the entire therapy.
People with low blood pressure (hypotension) are also at risk. Arginine, as a precursor of nitric oxide, can additionally reduce pressure, which is manifested by dizziness, weakness, dimmed vision on standing suddenly.
Medicines with which arginine is risky to combine
Drug interactions are the second major group of restrictions. They are mostly associated with an additive vasodilator effect or an effect on potassium levels. Below are the main groups of drugs, when taking which independent use of arginine is not recommended.
| Group of drugs | Examples | Possible risk |
|---|---|---|
| Organic nitrates | nitroglycerin, isosorbide mononitrate | excessive pressure reduction |
| PDE-5 inhibitors | sildenafil, tadalafil, vardenafil | increased vasodilatation, hypotension |
| Antihypertensive drugs | ACE inhibitors, sartans, calcium channel blockers | additive pressure reduction |
| Potassium-sparing diuretics | spironolactone, amiloride | theoretical risk of hyperkalemia |
| Anticoagulants and antiplatelet medicines | warfarin, clopidogrel | theoretical influence on platelet aggregation; a doctor's assessment is required |
| Drugs that reduce glucose | insulin, oral hypoglycemic agents | possible influence on glycemia, control is required |
It is especially worth emphasizing the combination with PDE-5 inhibitors. Arginine is often touted as a "natural potency enhancer" and sold in combinations that people take along with prescription drugs. For a person with damaged coronary vessels, an excessive drop in pressure can be dangerous.
Nitrates are an even more severe case: even the PDE-5 inhibitors themselves are categorically contraindicated together with nitrates. Adding another NO-dependent risk factor to such a situation is unacceptable without medical control.
Regarding anticoagulants and hypoglycemic drugs, there is little clinical data on serious interactions, but nitric oxide affects both platelets and insulin secretion. Therefore, people on such therapy should inform their doctor about any supplements.
Kidneys, liver and metabolism
In severe kidney and liver diseases, amino acid metabolism and potassium regulation are disturbed. For arginine hydrochloride, the ability to move potassium from cells into the blood is described; it is most documented for intravenous administration, but people with reduced kidney function should be cautious with oral doses as well.
The liver is the main site of the urea cycle, in which arginine is broken down to ornithine and urea. With cirrhosis and liver failure, this process is disturbed, and the load of additional amino acids should be evaluated by a doctor.
There are rare inborn errors of metabolism associated with arginine. For example, with arginase deficiency (hyperargininemia), the level of arginine in the blood is already elevated, and its additional intake is contraindicated. Such conditions are usually diagnosed in childhood, and patients are under the supervision of metabolic specialists.
People with diabetes should remember that arginine can influence the secretion of insulin and glucagon. This is not an absolute contraindication, but a reason to discuss any use with an endocrinologist and monitor glucose.
Special groups
The safety of arginine supplements has not been sufficiently studied for a number of groups, so self-administration should be avoided:
- pregnant and lactating women — arginine is studied in obstetrics for separate medical indications, but this is not a reason for self-administration;
- children and adolescents — the need is covered by the diet, and the described severe cases of intravenous arginine overdose in children remind us of the sensitivity of this group;
- people with frequent recurrences of herpes — the herpes simplex virus needs arginine for in vitro replication, so large doses are advised not to use;
- patients before scheduled surgery — due to the possible effect on blood pressure and platelets, taking supplements should be discussed with the surgeon and anesthesiologist;
- people with bronchial asthma or allergies — care should be taken with excipients and combination formulas.
We will separately mention people with diseases of the gastrointestinal tract - peptic ulcer disease, irritable bowel syndrome, inflammatory bowel diseases. For them, there is a high probability that even moderate doses of arginine will increase their symptoms.
Finally, the risk group should include athletes who simultaneously take several stimulants and vasodilators in pre-workout complexes. The total effect of such mixtures is difficult to predict.
How to make an informed decision
Before you buy arginine, answer a few questions honestly: do you have cardiovascular disease, do you regularly take any medications, do you have episodes of low blood pressure or digestive problems. If the answer to at least one question is "yes", the first step should be to consult a doctor.
During the visit, it is worth mentioning not only arginine, but also the entire composition of the pre-workout or "men's" complex that you plan to take. It is important for the doctor to see the whole picture, including caffeine, yohimbine and other active ingredients.
If the doctor sees no contraindications, it is reasonable to start with the minimum dose, monitor blood pressure during the first days of use and stop when dizziness, palpitations or stomach disorders appear.
It is also worth remembering that the evidence base for the benefits of arginine for healthy, trained people is weak. For people at risk, the benefit/risk balance is even less favorable, so often the best solution is to simply stop taking the supplement.
Editorial conclusions
The most serious limitation is previous myocardial infarction: according to the VINTAGE MI study, arginine showed no benefit and may have been associated with a worse prognosis.
Self-administration is not recommended for hypotension, taking nitrates, PDE-5 inhibitors, antihypertensive drugs, severe kidney and liver diseases, pregnant women and children.
We also recommend reading "L-Arginine Side Effects", "How to Take L-Arginine: Dosage, Timing, Duration" and "L-Arginine Benefits for Athletes: Evidence Base".
References
- Schulman SP, Becker LC, Kass DA, et al. L-arginine therapy in acute myocardial infarction: the Vascular Interaction With Age in Myocardial Infarction (VINTAGE MI) randomized clinical trial. JAMA. 2006;295(1):58â64.
- Shao A, Hathcock JN. Risk assessment for the amino acids taurine, L-glutamine and L-arginine. Regul Toxicol Pharmacol. 2008;50(3):376â399.
- Grimble GK. Adverse gastrointestinal effects of arginine and related amino acids. J Nutr. 2007;137(6 Suppl 2):1693Sâ1701S.
- Böger RH. The pharmacodynamics of L-arginine. J Nutr. 2007;137(6 Suppl 2):1650Sâ1655S.
- Wu G, Morris SM Jr. Arginine metabolism: nitric oxide and beyond. Biochem J. 1998;336(Pt 1):1â17.
