Side Effects and Warnings

Arginine has been well tolerated by most people in studies lasting for up to six months, although there is a possibility of serious adverse effects in some individuals.

Stomach discomfort, including nausea, stomach cramps or an increased number of stools, may occur. People with asthma may experience a worsening of symptoms if arginine is inhaled, which may be related to allergy. Headache has also been reported.

Other potential side effects include low blood pressure and changes in numerous chemicals and electrolytes in the blood. Examples include high potassium, high chloride, low sodium, low phosphate, high blood urea nitrogen and high creatinine levels. People with liver or kidney disease may be especially sensitive to these complications and should avoid using arginine except under medical supervision. After injections of arginine, low back pain, flushing, headache, numbness, restless legs, venous irritation and death of surrounding tissues have been reported.

In theory, arginine may increase the risk of bleeding. Patients using anticoagulants (blood thinners) or antiplatelet drugs, or with underlying bleeding disorders, should speak with a qualified healthcare provider before using arginine and should be monitored.

Arginine may increase blood sugar levels. Caution is advised in patients taking prescription drugs to control sugar levels.