L-Arginine - What is it & How to use

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for L-ARGININE are as follows:

Possibly effective for…

• Chest pain (angina). Taking L-arginine seems to decrease symptoms and improve exercise tolerance and quality of life in people with angina. However, L-arginine does not seem to help widen the blood vessels that are narrowed in angina.
• Erectile dysfunction (ED). Taking 5 grams of L-arginine by mouth daily seems to improve sexual function in men with ED. Taking lower doses might not be effective. However, there is some early evidence that taking L-arginine with maritime pine bark extract and other ingredients, might improve the effectiveness of low-dose L-arginine for ED.
• High blood pressure. There is early evidence that taking L-arginine by mouth can reduce blood pressure in healthy people, people with high blood pressure, and people with slightly high blood pressure with or without diabetes.
• Inflammation and tissue death in the digestive tract in premature infants (necrotizing enterocolitis). Adding L-arginine to formula seems to prevent inflammation of the digestive tract in premature infants. A total of 5 premature infants need to receive arginine to prevent one instance of digestive tract inflammation.
• Nitrate tolerance. Taking L-arginine by mouth seems to prevent nitrate tolerance in people taking nitroglycerin for chest pain (angina pectoris).
• Leg pain associated with poor blood flow (peripheral arterial disease). Research suggests that taking L-arginine by mouth or intravenously (by IV) for up to 8 weeks increases blood flow in people with peripheral arterial disease. However, long-term use (up to 6 months) does not improve walking speed or distance in people with peripheral arterial disease.
• Improving recovery after surgery. Taking L-arginine with ribonucleic acid (RNA) and eicosapentaenoic acid (EPA) before surgery or afterwards seems to help reduce the recovery time, reduce the number of infections, and improve wound healing after surgery.
• High blood pressure during pregnancy (pre-eclampsia). Most research shows that L-arginine can reduce blood pressure in women with this condition. L-arginine might also prevent this condition in pregnant women.

Possibly ineffective for…

• Kidney disease. Most early research suggests that taking L-arginine by mouth or intravenously (by IV) does not improve kidney function in most people with kidney failure or kidney disease. However, taking L-arginine by mouth might improve kidney function and reverse anemia in elderly people with kidney disease-associated anemia.
• Heart attack. Taking L-arginine does not seem to help prevent a heart attack. It also does not seem to be beneficial for treating a heart attack after it has occurs. In fact, there is concern that L-arginine might be harmful for people after a recent heart attack. Do not take L-arginine if you have had a recent heart attack.
• Tuberculosis. Adding arginine to standard treatment for tuberculosis does not seem to help improve symptoms or clear the infection.
• Wound healing. Taking L-arginine does not seem to improve wound healing.

Insufficient evidence to rate effectiveness for…

• AIDS-related wasting. Taking L-arginine by mouth, along with hydroxymethylbutyrate (HMB) and glutamine, for 8 weeks seems to increase body weight and improve immune function in people with HIV/AIDS. However, taking L-arginine by mouth, along with omega-3 fatty acids and a balanced nutritional supplement, for 6 months does not improve body weight or fat mass, energy intake, or immune function in people who are HIV-positive.
• Altitude sickness. Early research suggests that L-arginine does not reduce altitude sickness.
• Anal fissures. There is inconsistent evidence about that effects of L-arginine for treating anal fissures. Applying a topical gel containing L-arginine for at least 12 weeks might heal anal fissures in people who do not respond to traditional care. However, applying L-arginine to the skin does not seem to be better than surgery for anal fissures.
• Breast cancer. Early research shows that taking L-arginine before chemotherapy does not improve the response rate in people with breast cancer.
• Heart failure. Taking L-arginine by mouth, together with conventional treatment, seems to improve kidney function in people with heart failure. However, it might not improve the ability to exercise, quality of life, or blood circulation. L-arginine should not be used in place of conventional treatment.
• Coronary artery bypass graft (CABG) surgery. There is mixed evidence about the effects of L-arginine in protecting the heart during CABG. Some research suggests that giving L-arginine intravenously (by IV) may be helpful in people undergoing CABG. Other research shows that it does not help.
• Clogged blood vessels (coronary artery disease). Early research suggests that taking L-arginine intravenously (by IV) before exercising can improve blood vessel function in people with coronary artery disease. However, it does not improve blood flow to the heart.
• Critical illness (trauma). Research shows that taking L-arginine by mouth with glutamine, nucleotides, and omega-3 fatty acids reduces the recovery time, the need for help with breathing, and risk of infections in people who are critically ill. However, it does not reduce the risk of death.
• Memory loss (dementia). Early research suggests that L-arginine might improve memory loss related to aging.
• Cavities. Early research suggests that using a sugarless mint containing an arginine complex (CaviStat) for one year reduces the number of cavities in molars of children compared with sugarless mints that do not contain arginine.
• Sensitive teeth. Early research suggests that using a toothpaste containing arginine, calcium, and fluoride reduces tooth sensitivity when used twice daily.
• Diabetes. Taking L-arginine by mouth seems to improve blood sugar control in people with existing diabetes. However, it is unclear if arginine helps prevent people with pre-diabetes from developing diabetes.
• Diabetic foot ulcers. Early research shows that applying L-arginine to the feet daily can improve circulation in people with diabetes, which might be helpful in preventing diabetic foot ulcers. However, if there is already an ulcer on the foot, injecting L-arginine under the skin near the ulcer does not seem to shorten healing time or lower the chance of needing an amputation in the future.
• Nerve damage due to diabetes. Early research suggests that taking L-arginine daily for 3 months does not improve nerve damage related to diabetes.
• Muscle problems in the esophagus. Early research suggests that taking L-arginine by mouth or as an infusion can reduces the number and intensity of chest pain attacks in people with chest pain that is not related to the heart.
• Exercise performance. There is inconsistent evidence about the effects of L-arginine on exercise performance. Some evidence shows that taking 6 grams of L-arginine in a drink increases exercise time until becoming tired. Also taking arginine with grape seed extract appears to improve working ability in men and decreases their tiredness. However, taking arginine 6 grams once does not affect strength during exercise.
• Head and neck cancer. Supplementing a feeding tube with L-arginine does not seem to improve immune function, reduce tumor size, or improve healing in people with head and neck cancer.
• Heart transplant. Early research suggests that taking L-arginine by mouth for 6 weeks increases walking distance and improves breathing in people with a heart transplant.
• Infertility. There is inconsistent evidence about the effectiveness of L-arginine for infertility. Some early research suggests that taking 16 grams of L-arginine daily increases egg counts collected in women undergoing IVF. However, it does not seem to improve pregnancy rates. Other research suggests that taking L-arginine does not improve semen quality in men with unexplained infertility.
• Bladder inflammation. Taking L-arginine by mouth seems to reduce pain and some symptoms of bladder inflammation, although improvements may take 3 months to occur. However, L-arginine does not seem to reduce the need to urinate at night or improve the frequency of urination.
• Poor growth of fetus during pregnancy. Early research suggests that taking L-arginine during pregnancy can increase the birthweight of babies who show poor growth while still in their mother’s womb. However, L-arginine does not seem to increase birthweight or reduce the risk of the baby dying if the baby has extremely poor growth while in the womb.
• Mitochondrial encephalomyopathies (a group of disorders that lead to muscle and nervous system problems). There is some interest in using L-arginine to improve symptoms associated with MELAS (myoclonic epilepsy with lactic acidosis and stroke-like episodes) syndrome. Early research suggests that administering L-arginine intravenously (by IV) within one hour of stroke-like symptoms improves headaches, nausea, vomiting, blindness, and the appearance of bright spots in people with this condition.
• Migraine headache. Taking L-arginine by mouth along with the painkiller ibuprofen seems to be effective for treating migraine headache. This combination sometimes starts to work within 30 minutes. However, it is hard to know how much of the pain relief is due to L-arginine, since ibuprofen can relieve migraine pain on its own.
• Obesity. Early research suggests that taking a specific arginine supplement (NOW Foods, Bloomingdale, IL) 3 grams three times daily may decrease waist size and weight in women .
• Ovarian disease (polycystic ovarian syndrome). Early research suggests that taking N-acetyl-cysteine and L-arginine daily for 6 months can improve menstrual function and reduces insulin resistance in people with polycystic ovarian syndrome.
• Pressure ulcers. Taking L-arginine by mouth along with the painkiller ibuprofen seems to be effective for treating migraine headache. This combination sometimes starts to work within 30 minutes. However, it is hard to know how much of the pain relief is due to L-arginine, since ibuprofen can relieve migraine pain on its own.
• Restricted blood flow (restenosis). Some research suggests that giving L-arginine during stent implantation followed by L-arginine supplementation by mouth for 2 weeks after stent implantation does not reduce the risk of restricted blood flow. However, other evidence suggests that administering L-arginine at the site of stent implantation may reduce artery wall thickening.
• Kidney transplant. There is conflicting evidence about the effects of L-arginine for people with kidney transplants. It is unclear if it helps.
• Respiratory infections. Early research suggests that taking L-arginine by mouth for 60 days prevents the recurrence of respiratory infections in children.
• Sickle-cell disease. Early research suggests that taking L-arginine for 5 days might be useful for people with sickle cell disease who have high blood pressure in the lungs.
• Stress. Some early research suggests that taking a combination of L-lysine and L-arginine for up to 10 days reduces stress and anxiety in healthy people and those prone to stress.
• Prevention of the common cold.
• Female sexual problems.

More evidence is needed to rate the effectiveness of L-arginine for these uses.