L-Arginine is an amino acid found in many foods and is the precursor to one of the most potent vasodilators, called nitric oxide. This opens the blood vessels and increases circulation to the heart muscle as well as to peripheral tissues. Because of this, L-Arginine is often used for congestive heart failure, angina, coronary artery disease and erectile dysfunction. Arginine is also one of the main components of human growth hormone, and so it can be taken before a workout or before bed to boost growth hormone naturally. L-Arginine is widely used for its health benefits, but it is important to remember that there are risks as well.
Low Blood Pressure
L-Arginine is used to open the blood vessels and increase circulation, which is generally a positive thing. It can, however, lead to unusually low blood pressure if it is used in large quantities. Opening the blood vessels means that there is more space in the vessels for the same amount of blood, which leads to a decrease in pressure.
Because of its dramatic effect on blood vessels, L-Arginine can cause headaches as a side effect in some individuals. L-Arginine opens the blood vessels throughout the body, including those within the brain. For some people, that leads to headaches, especially in people prone to tension headaches and migraines.
Increase in Herpes Outbreaks
The herpes virus, type I and II, feeds on L-Arginine and is suppressed by another amino acid, L-Lysine. If the ratio of Arginine to Lysine is tipped in favor of Arginine, outbreaks can be more frequent and more severe. This applies to both oral and genital herpes, so caution should be used if you have have had an outbreak in the past.
Anyone who has suffered through an attack of gout will do almost anything to avoid another one. Gout is a debilitating splinter-like pain in joints, most often the joint in the big toe. It is most notoriously triggered by rich foods and alcohol but can also be triggered by L-Arginine, which is often found in high amounts in many of the causative foods, such as steak and shell fish. If you suffer with gout, introduce L-Arginine slowly, because gout symptoms are more likely at high doses.
Interactions with Medications
Again because of its potent vasodilating effects, L-Arginine can interact with medications that have a similar action. This includes nitroglycerine, which is used predominantly for chest pain, as well as drugs for erectile dysfunction, which are also potent vasodilators. Medications to lower the blood pressure may be enhanced by the use of Arginine, which increases the chances for dangerously low numbers. Conversely, it can reduce the effectiveness of drugs that cause the blood vessels to become more narrow, especially drugs that are designed to reduce blood flow to the brain to ease pain in migraine sufferers. Talk with your doctor to make sure there are no interactions between medications you take and supplements you would like to start.
Some people who have taken L-Arginine have reported feelings of abdominal pain, bloating and diarrhea. The reasons for these symptoms are unknown but may be related to increased blood flow to the digestive organs.
Allergies and Asthma
In rare cases, taking L-Arginine can make asthma and allergy symptoms more severe. If you suffer from asthma, talk with your doctor before starting L-Arginine, and carry your rescue inhaler with you at all times.