This article explains what L-arginine is and whether the evidence supports its use for treating high blood pressure.
What Is L-Arginine?
L-arginine (also known simply as 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 keep 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 constricted blood vessels. This deficiency can lead to problems, including high blood pressure, erectile dysfunction, and kidney filtering problems.
Studies have noted that a lack of arginine can lead to a decrease in nitric oxide available in the body.
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.
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 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.
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 received 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 among people at risk of developing preeclampsia and those with existing hypertension. It also reduced the risk of preterm birth.
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.
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.
Food sources of L-arginine include:
Soy protein Peanuts Walnuts Fish Cereals and grains
Potential Risks
In the 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 common these side effects might be.
L-arginine can have harmful drug interactions, and it may be unsafe to take it with medications used for treating high blood pressure, blood thinners, or other medications that affect blood vessel dilation.
Summary
Once a relatively rare product, L-arginine supplements have grown in popularity. Companies that produce the supplements claim beneficial effects including 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. Supplements, herbal medicine, and natural remedies are increasingly marketed to people with high blood pressure. Although there is insufficient evidence to support L-arginine supplements for treating high blood pressure, it can be safe for some people.
As with any medication or supplement, be sure to talk to your doctor before taking L-arginine.
