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 2.5 or 5 grams of L-arginine by mouth daily seems to improve sexual function in men with ED. Taking lower doses might not be effective. But 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. Taking L-arginine with medications for ED might be more effective than taking the medications alone.
- High blood pressure. There is 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.
- A serious intestinal disease in premature infants (necrotizing enterocolitis or NEC). Adding L-arginine to formula seems to prevent inflammation of the digestive tract in premature infants. A total of 6 premature infants need to receive arginine to prevent one instance of digestive tract inflammation.
- Narrowing of blood vessels causes poor blood flow to the limbs (peripheral arterial disease). Research shows 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 these same people.
- A pregnancy complication marked by high blood pressure and protein in the urine (pre-eclampsia). Most research shows that L-arginine can reduce blood pressure in pregnant women with pre-eclampsia. L-arginine also seems to keep pregnant women from developing pre-eclampsia.
- High blood pressure during pregnancy. Taking L-arginine intravenously (by IV) can reduce blood pressure in pregnant women who develop high blood pressure. It’s unclear if taking L-arginine by mouth lowers blood pressure during pregnancy, but it might decrease the need to take blood pressure-lowering drugs.
Possibly ineffective for…
- Long-term kidney disease (chronic kidney disease or CKD). 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 occurred. 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.
- High cholesterol. Most research shows that taking L-arginine doesn’t help to lower cholesterol levels.
- 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…
- Altitude sickness. Early research suggests that L-arginine does not reduce altitude sickness.
- Small tears in the lining of the anus (anal fissures). There is inconsistent evidence about the 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.
- Athletic performance. There is inconsistent evidence about the effects of L-arginine on athletic performance. L-arginine might help people exercise longer, but it does not seem to help make people stronger. Some evidence shows that taking L-arginine increases the time a person can exercise before becoming tired and helps the lungs work more efficiently. However, taking L-arginine does not affect strength during exercise.
- Breast cancer. Early research shows that taking L-arginine before chemotherapy does not improve the response rate in people with breast cancer.
- Heart failure and fluid build up in the body (congestive heart failure or CHF). Taking L-arginine by mouth, together with conventional treatment, seems to improve kidney function in people with heart failure. But it doesn’t seem to improve the ability to exercise. L-arginine should not be used in place of conventional treatment.
- Surgery to improve blood flow to the heart (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.
- Heart disease. Early research suggests that taking L-arginine intravenously (by IV) before exercising can improve blood vessel function in people with heart disease. However, it does not improve blood flow to the heart.
- Cystic fibrosis. Early research shows that breathing in a solution containing L-arginine does not improve lung function any more than breathing in saline.
- Diseases, such as Alzheimer’s disease, that interfere with thinking (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. Also, using a toothpaste containing arginine, calcium, and fluoride reduces cavity production by a small amount compared to toothpaste containing the only fluoride.
- Tooth sensitivity. 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.
- Foot sores in people with diabetes. 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. Taking L-arginine by mouth with other amino acids doesn’t seem to help foot ulcers heal better in most people with diabetes. But it might help people with diabetes who have low levels of protein in the blood or those with poor circulation to the feet.
- Nerve pain in people with diabetes (diabetic neuropathy). Early research suggests that taking L-arginine daily for 3 months does not improve nerve damage related to diabetes.
- Chest pain with no apparent cause (functional chest pain). Early research suggests that taking L-arginine by mouth or as an infusion can reduce the number and intensity of chest pain attacks in people with chest pain that is not related to the heart.
- 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 failure. Early research shows that taking L-arginine by mouth or receiving L-arginine by IV does not seem to improve a person’s ability to exercise, quality of life, or blood circulation. L-arginine should not be used in place of conventional treatment.
- Complications after a 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.
- Involuntary weight loss in people with HIV/AIDS. 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.
- Inability to become pregnant within a year of trying to conceive (infertility). Some early research suggests that taking 16 grams of L-arginine daily increases the number of eggs collected in women undergoing IVF. However, it does not seem to improve pregnancy rates.
- Painful bladder syndrome (interstitial cystitis). 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.
- Infants with a birth weight below the 10th percentile due to inadequate nutrition. Early research suggests that taking L-arginine during pregnancy can increase the birth weight 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.
- Kidney transplant. There is conflicting evidence about the effects of L-arginine on people with kidney transplants. It is unclear if it helps.
- Conditions in a man that prevent him from getting a woman pregnant within a year of trying to conceive (male infertility). Early research shows that taking L-arginine does not improve sperm function or count in men with unexplained infertility. However, taking L-arginine with maritime pine bark extract might help sperm move faster.
- A group of disorders that most often cause muscle weakness (mitochondrial myopathies). There is some interest in using L-arginine to improve symptoms associated with MELAS. Early research suggests that administering L-arginine intravenously (by IV) soon after stroke-like symptoms improves headaches, nausea, vomiting, blindness, and the appearance of bright spots in the eyes. Some research also shows that taking L-arginine every day might reduce the risk of stroke-like symptoms. But not all research agrees.
- Migraine. Taking L-arginine by mouth along with the painkiller ibuprofen seems to be effective for treating migraine headaches. 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.
- A group of inherited disorders that cause muscle weakness and muscle loss (muscular dystrophy). Very early research suggests that taking L-arginine with a drug called metformin might help with muscle control and walking ability in children with Duchenne muscular dystrophy.
- The reduced benefit of nitrate therapy happens when nitrates are used all day (nitrate tolerance). Taking L-arginine by mouth seems to prevent tolerance in people who take nitroglycerin for chest pain.
- Obesity. Early research shows that taking arginine may decrease waist size and weight in women.
- Physical performance in elderly adults. Early research in active elderly women shows that taking L-arginine by mouth doesn’t improve leg strength or performance on tests that measure the ability to complete certain daily activities like standing up from a chair.
- A hormonal disorder that causes enlarged ovaries with cysts (polycystic ovary syndrome or PCOS). 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 the polycystic ovarian syndrome.
- Infection after surgery. Taking L-arginine with other compounds before surgery or after surgery seems to help reduce the number of infections after surgery. But L-arginine probably does not work when taken by itself.
- Re-narrowing of a blood vessel after stent placement or angioplasty (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.
- Infection of the airways. Early research suggests that taking L-arginine by mouth for 60 days prevents the recurrence of respiratory infections in children.
- Schizophrenia. Early research shows that taking L-arginine does not help people with schizophrenia who are already using appropriate treatment.
- Sickle-cell disease. Early research shows that taking L-arginine by mouth or as an injection (by IV) for 5 days might be useful for adults with sickle cell disease who have high blood pressure in the lungs. It might also help to reduce the amount of pain medications needed to control pain in children who are in the hospital because of a sickle cell attack (sickle cell crisis).
- Toxic side effects caused by the drug valproic acid. Giving L-arginine intravenously (by IV) might reduce high levels of ammonia in the blood during treatment with valproic acid in some people.
- Swelling (inflammation) and sores inside the mouth (oral mucositis). Early research shows that taking L-arginine by mouth along with other ingredients does not prevent sores in the mouth during cancer treatment.
- Bedsores (pressure ulcers).
- Child growth.
- Critical illness (trauma).
- Prevention of the common cold.
- Recovery after surgery.
- Sexual problems that prevent satisfaction during sexual activity.
- Skin damage caused by radiation therapy (radiation dermatitis).
- Other conditions.
More evidence is needed to rate the effectiveness for these uses.
Side Effects Of L-Arginine
- When taken by mouth: L-arginine is POSSIBLY SAFE for most people when taken appropriately by mouth, short-term. It can cause some side effects such as abdominal pain, bloating, diarrhea, gout, allergies, worsening of asthma, and low blood pressure.
- When applied to the skin: L-arginine is POSSIBLY SAFE for most people when applied to the skin or used in toothpaste, short-term.
- When inhaled: L-arginine is POSSIBLY SAFE for most people when inhaled, short-term.
- When given as a shot: L-arginine is POSSIBLY SAFE for most people when given as a shot, short-term. It can cause some side effects such as nausea, vomiting, and blood abnormalities.
Warnings & Precautions
- Pregnancy and breast-feeding: L-arginine is POSSIBLY SAFE when taken by mouth appropriately for a short time during pregnancy. Not enough is known about using L-arginine long-term in pregnancy or during breast-feeding. Stay on the safe side and avoid use.
- Children: L-arginine is POSSIBLY SAFE in children when taken by mouth in appropriate doses when used in toothpaste, when given as an injection (by IV), or when inhaled. However, it is POSSIBLY UNSAFE when given as an injection (by IV) in high doses. Doses that are too high can cause serious side effects, including death, in children.
- Allergies or asthma: L-arginine can cause an allergic response or make swelling in the airways worse. If you are prone to allergies or asthma and decide to take L-arginine, use it with caution.
- Cirrhosis: L-arginine should be used with caution in people with cirrhosis.
- Guanidinoacetate methyltransferase deficiency: People with this inherited condition are unable to convert arginine and other similar chemicals into creatine. To prevent complications associated with this condition, these people should not take arginine.
- Herpes: There is a concern that L-arginine might make herpes worse. There is some evidence that L-arginine is needed for the herpes virus to multiply.
- Low blood pressure: L-arginine might lower blood pressure. This could be a problem if you already have low blood pressure.
- Recent heart attack: There is a concern that it might increase the risk of death after a heart attack, especially in older people. If you have had a heart attack recently, don’t take L-arginine.
- Kidney disease: L-arginine has caused high potassium levels when used by people with kidney disease. In some cases, this has resulted in a potentially life-threatening irregular heartbeat.
- Surgery: L-arginine might affect blood pressure. There is a concern that it might interfere with blood pressure control during and after surgery. Stop taking L-arginine at least 2 weeks before a scheduled surgery.
Dosage Of L-Arginine
The following doses have been studied in scientific research:
- For chest pain (angina): 2-6 grams three times per day for up to one month.
- For erectile dysfunction (ED): 2.5-5 grams per day. Taking lower doses might not be effective.
- For high blood pressure: 4-24 grams per day for 2-24 weeks.
- For narrowing of blood vessels that causes poor blood flow to the limbs (peripheral arterial disease): 6-24 grams for up to 8 weeks.
- For a pregnancy complication marked by high blood pressure and protein in the urine (pre-eclampsia): 3 grams per day for up to 3 weeks for the treatment of pre-eclampsia, and 3 grams per day starting at 20 weeks gestation for the prevention of pre-eclampsia. Two bars of a medical food (Heart Bars) with arginine 6.6 grams and antioxidant vitamins per day starting at 14-32 weeks gestation and continuing until delivery for the prevention of pre-eclampsia.
- For high blood pressure during pregnancy: 4 grams per day for 10-12 weeks.
- For narrowing of blood vessels that causes poor blood flow to the limbs (peripheral arterial disease): 16 grams for up to 8 weeks.
- For a pregnancy complication marked by high blood pressure and protein in the urine (pre-eclampsia): 20 grams per day for up to 5 days or one 30 gram dose.
- For high blood pressure during pregnancy: 20 grams per day for up to 5 days.
For a serious intestinal disease in premature infants (necrotizing enterocolitis or NEC): 261 mg/kg added to oral feedings daily for the first 28 days of life.
Consult your doctor or pharmacist.
All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.