What are Arginine Side Effects?

Sandy Baker

Arginine, an essential amino acid normally produced in the body, may have side effects when supplementation is necessary. These side effects can include an allergic reaction, which can cause shortness of breath, itching, and rash; nausea and stomach pain; and changes in blood chemicals. In addition, people with liver and kidney diseases or diabetes may suffer reactions specific to their conditions. Most people tolerate arginine supplements well, however; in clinical trials lasting up to six months, few people had significant side effects.

Headaches are a commonly reported side effect of arginine.
Headaches are a commonly reported side effect of arginine.

The most significant arginine side effect is an allergic reaction. This can occur in any supplement form, but occurs more frequently when it is given by injection. Signs of an allergic reaction to the supplement include shortness of breath, itching, burning, and rash. Those who have a known allergy to the substance should not use it in supplemental form.

L-arginine may have severe side effects for asthmatics who use inhalers.
L-arginine may have severe side effects for asthmatics who use inhalers.

L-arginine, as this amino acid is called in its supplement form, may have other side effects as well. L-arginine side effects include nausea, cramping in the abdomen, stomach pain, and increased stools. These arginine side effects may be more severe for those who use an inhaled supplement and who have asthma. Abdominal pain and diarrhea may be moderate to severe. In some people, gout develops.

Nausea may occur while taking arginine.
Nausea may occur while taking arginine.

Some of the advanced symptoms of L-arginine side effects occur when the substance in injected into the body. Individuals may experience flushing, headaches, and lower back pain. In some individuals, restless legs and venous irritation may occur, which is an inflammation at the source of the injection. In some cases, injections can lead to death of the tissues surrounding the injection site.

An allergic reaction to arginine can cause stomach pain.
An allergic reaction to arginine can cause stomach pain.

Other arginine side effects occur within the blood, including changes in blood chemicals and electrolytes. Low blood pressure can be a sign of this side effect. In some people, high potassium, low sodium, high blood urea nitrogen, and high chloride levels may occur. High creatine levels may also be a side effect.

Arginine side effects may be more significant in those who have liver or kidney diseases. In these individuals, the use of arginine supplementation should be conducted only with doctor approval and guidance. High levels of arginine consumption can lead to strain on the liver and kidneys.

For those who have diabetes or blood sugar concerns, arginine side effects may be significant. Arginine can increase blood sugar levels in some individuals. This spike in blood sugar can be especially dangerous to those already taking medications to control blood sugar.

Anytime side effects are serious or get progressively worse, the patient should contact a doctor. Although arginine side effects are minor or nonexistent in most people, for other people these symptoms can be life threatening. Supplement users should follow recommended dosing instructions to reduce the risk of side effects.

Diarrhea is one possible side effect of arginine.
Diarrhea is one possible side effect of arginine.

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Discussion Comments


I'm a diabetic. I was taking arginine but had to quit because my blood sugar increased. Diabetics should avoid this supplement altogether. Some sources claim that arginine can reduce blood sugar but that's not true.


L-arginine does have side effects but I think that most of them are related to the dose. Most of us forget that l-arginine is also found in food and it's possible to get too much of it and experience toxicity.

When there are side effects like headaches, it could be a sign of toxicity. That's why I have lowered my l-arginine dosage and I take a break from my supplement for a few days every week.


I'm always hearing great things about l-arginine and I know that l-arginine has many benefits. But it has not worked out for me because of the gastrointestinal side effects.

When I first started taking it, I experienced upset stomach and nausea. I was taking the supplement on an empty stomach, so I started taking it after meals and that seemed to resolve these issues. But after using the supplement for several more days, I developed diarrhea. I took a break from l-arginine for a while and tried it once again to see if the diarrhea was due to something else. But no, it gave me diarrhea again. I just can't take it, my body doesn't tolerate it well.

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