Does L-Arginine Lower Blood Pressure?

L-Arginine Supplements Claim to have Beneficial Blood Pressure Effects

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Supplements, herbal medicine, and natural remedies are increasingly marketed to people with high blood pressure. For example, L-arginine is a supplement available at many retailers and online shops that claim to have beneficial blood pressure effects.

This article explains what L-arginine is and whether the evidence supports its use for treating high blood pressure.

Blood pressure monitor
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What Is L-Arginine?

L-arginine (also known as simply arginine) is an amino acid that the body uses to produce the chemical nitric oxide. This chemical is a potent vasodilator, which means it helps blood vessels open.

Nitric oxide plays a significant role in the health of blood vessels.

  • More nitric oxide causes blood vessels to relax and dilate. This process lowers blood pressure.
  • Too little nitric oxide can result in tense blood vessels. This deficiency can lead to problems including high blood pressure, erectile dysfunction, and kidney filtering problems.

Studies on nitric oxide have noted how it impacts various processes in the body that rely on arginine. Specifically, a lack of arginine can lead to a decrease in nitric oxide available in the body.

Arginine is a non-toxic substance that the body can easily excrete. Therefore, supplementing with arginine seems like an easy way to avoid problems associated with low nitric oxide levels.

Evidence in Animals

Early studies done in animals showed that arginine supplementation does lead to measurable declines in blood pressure. Therefore, proponents sometimes cite these studies 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 rats and in settings where researchers strictly controlled their diet. Therefore, these findings may not necessarily translate to humans.

Research into the effects of arginine was not designed to test its impact on blood pressure. Instead, researchers investigated the function of specific chemical and cellular systems in great detail.

Evidence in Humans

A 2016 umbrella review of meta-analyses found that L-arginine reduces systolic and diastolic blood pressure in adults with hypertension. In addition, it found that it reduced diastolic blood pressure in pregnant people with gestational hypertension.

Even so, the authors advise approaching the results with caution because of the variability of the studies.

In addition, some studies have indicated that L-arginine lowers the risk of developing preeclampsia during pregnancy. Preeclampsia is a pregnancy complication marked by high blood pressure.

  • In one study, researchers gave 50 participants a placebo and 50 L-arginine. The placebo group had significantly more preeclampsia cases than the L-arginine group.
  • A systematic review of randomized trials found that L-arginine reduced the risk of developing preeclampsia. L-arginine reduced this risk for people at risk of developing preeclampsia and for those with existing hypertension. It also reduced the risk of preterm birth.

While these results are promising, the authors urge caution. That's because the sample sizes were small, and the impact of supplementation on maternal and infant health is unknown.

An important thing to keep in mind is that arginine has to pass through the digestive tract when you take it orally. This pathway is an inefficient way to get it to the places where it could produce nitric oxide.

Furthermore, as an amino acid, arginine is a part of animal and plant proteins, so it is usually plentiful in a well-balanced diet.

Food sources of L-arginine include:

  • Soy protein
  • Peanuts
  • Walnuts
  • Fish
  • Cereals and grains

Unless researchers find evidence showing clear benefits, investing in a healthy diet that includes animal and plant proteins would be more effective. These whole foods have a clear and well-established impact on overall health.

Potential Risks

In the umbrella review mentioned above, some participants noted gastrointestinal side effects from taking a daily L-arginine supplement. These side effects included diarrhea and nausea. However, the sample size was small. So, it is unclear how prolific these side effects might be.

Summary

Once a relatively rare product, L-arginine supplements have grown in popularity. Companies that produce the supplements claim beneficial effects ranging from increased muscle endurance to reduced blood pressure. However, there is insufficient evidence to support these claims.

A Word From Verywell

If you have high blood pressure, you might be looking for holistic ways to lower your blood pressure. Although there is insufficient evidence to support L-arginine supplements for treating high blood pressure, it probably won't hurt either.

As with any medication or supplement, be sure to talk to your doctor about your unique situation before taking L-arginine.

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2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  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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