Does L-Arginine Lower Blood Pressure?

L-Arginine Supplements Claim to have Beneficial Blood Pressure Effects

As the worldwide supplement market continues to grow and blend with the fields of herbal medicine and natural remedies, an increasing number of products are marketed to people with high blood pressure. L-arginine is a supplement available at many retailers and online shops that claim to have beneficial blood pressure effects.

Blood pressure monitor
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Why Is L-Arginine Growing in Popularity?

Once a relatively rare product, l-arginine supplements have been growing in popularity thanks to the successful marketing efforts of health food chains and the popular press. Companies that produce the supplements claim beneficial effects ranging from increased muscle endurance to reduced blood pressure.

What Is L-Arginine?

On the surface, these claims make sense. L-arginine (also known as simply arginine) is an amino acid that the body uses to produce the chemical nitric oxide, a powerful vasodilator. Nitric oxide plays a large role in regulating the tone of blood vessels. More nitric oxide causes blood vessels to relax and dilate, which lowers blood pressure. A deficiency of nitric oxide can lead to tense blood vessels and cause problems including high blood pressure, erectile dysfunction, and impaired kidney filtering.

Studies on nitric oxide have shown direct links to various processes in the body that rely on arginine. A lack of arginine at any one of many points can lead to a decrease in the amount of nitric oxide available in the body. Since arginine tends to be in short supply anyway, and since it is a non-toxic substance that is easily excreted by the body if there is too much, supplementing arginine levels seems like an easy way to avoid problems associated with low levels of nitric oxide.

Studies Show L-Arginine Lowers Blood Pressure in Animals

Studies done in animals have shown some that arginine supplementation does lead to measurable declines in blood pressure, and these studies are sometimes cited as “evidence” that arginine supplements are a good, “natural” treatment for high blood pressure. However, it is important to note that these studies were done in very specific types of animals and in settings where every other dietary input was strictly controlled. Research into the effects of arginine is actually not designed to test its ability to affect blood pressure, but rather to investigate the functioning of certain chemical and cellular systems in great detail.

No Evidence L-Arginine Lowers Blood Pressure in Humans

There is no evidence that arginine supplementation has any beneficial effects on blood pressure in humans. In fact, it is likely that taking arginine supplements wouldn’t have any effect at all. This is because arginine ingested orally has to pass through the digestive tract, which is not an efficient or useful way to get it to the places where it would be able to affect nitric oxide synthesis. Furthermore, the need for supplementation is dubious since, as an amino acid, arginine is a part of both the animal and plant proteins present in a well-balanced diet.

Unless evidence showing clear benefits is demonstrated, it would be more effective to spend the same amount of money on fresh fruits and vegetables, which do have a clear and well-established impact on overall health.

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  1. Rajapakse NW, Mattson DL. Role of L-arginine in nitric oxide production in health and hypertension. Clin Exp Pharmacol Physiol. 2009;36(3):249-55. doi:10.1111/j.1440-1681.2008.05123.x

  2. Patel A, Layne S, Watts D, Kirchner KA. L-arginine administration normalizes pressure natriuresis in hypertensive Dahl rats. Hypertension. 1993;22(6):863-9. doi:10.1161/01.hyp.22.6.863

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