L-arginine is a type of amino acid. Amino acids are the building blocks of protein, which is key for the health of your muscles and immune system.
Certain amino acids may serve additional purposes. For instance, L-arginine supports healthy blood pressure levels and helps treat erectile dysfunction. L-arginine is a vasodilator, meaning it can help improve blood circulation and bring more oxygen to muscles throughout the body.
L-arginine is a non-essential amino acid, which means the body naturally produces the substance on its own. The body does this by converting L-citrulline, another amino acid, to L-arginine in the kidneys. L-arginine is also naturally found in protein-rich foods, such as meat, dairy, nuts, and seeds.
But supplementing with L-arginine may bring even more benefits and be helpful in the management of certain health conditions.
Dietary supplements are minimally regulated by the FDA and may or may not be suitable for you. The effects of supplements vary from person to person and depend on many variables, including type, dosage, frequency of use, and interactions with current medications. Please speak with your healthcare provider or pharmacist before starting any supplements.
In the body, L-arginine isconverted into nitric oxide, a molecule that widens blood vessels to improve blood flow. This can help lower blood pressure levels and maintain healthy circulation.
Research has shown L-arginine can reduce systolic and diastolic blood pressure in people with or without high blood pressure.
Some small studies suggest intravenous (IV) L-arginine supplementation, which is treatment delivered directly into the vein through an IV drip, may also help manage high blood pressure. It may also help treat preeclampsia, which is high blood pressure during pregnancy.
There is some evidence taking oral L-arginine supplements early in pregnancy may help prevent the onset of preeclampsia. However, more research is needed to confirm this potential benefit.
May Enhance Exercise Performance
Since L-arginine helps deliver blood, oxygen, and other nutrients to working skeletal muscles, it’s possible the amino acid may improve exercise performance.
L-arginine also helps speed up the removal of materials like lactate and ammonia from the body, which can lead to fatigue during physical activity. Plus, L-arginine aids in the formation of creatine, another amino acid that provides fuel to muscles during high-intensity exercise.
However, studies in this area have produced conflicting results. Some researchers have concluded the evidence is lacking on whether L-arginine supplementation improves athletic performance or recovery.
Angina is a type of chest pain caused by insufficient blood flow to the heart. L-arginine supplementation may help manage symptoms associated with angina and improve exercise tolerance for people with angina.
This benefit may be due to L-arginine’s ability to promote healthy circulation. However, there is not enough evidence to show that the amino acid helps treat narrowed blood vessels that may be related to angina.
Improves Erectile Dysfunction
L-arginine may help boost sexual function, especially when paired with other erectile dysfunction (ED) medications.
Research has shown L-arginine supplements taken in combination with ED medications like PDE5 inhibitors can significantly improve sexual function in people diagnosed with ED.
When L-arginine is converted into nitric oxide, it can help promote blood flow, bring more oxygen throughout the body, and smooth muscle relaxation. All of these factors are essential for erections.
Necrotizing enterocolitis (NEC) is a condition that can affect the digestive systems of premature infants. Research has shownoral L-arginine supplementation significantly reduced the risk of NEC in premature infants when compared to a placebo. However, more studies on larger populations are needed to recommend this as a treatment.
How to Take L-Arginine
Supplemental L-arginine can be given orally in a capsule, topically as a gel or cream, or intravenously in a clinical setting.
L-arginine can also be consumed through several protein-rich food sources. The amino acid is found naturally in the following foods:
- Meat
- Poultry (chicken, eggs)
- Fish
- Nuts and seeds
- Legumes (beans, lentils)
Dosage
Most research suggests L-arginine supplements are well-tolerated in doses of up to 9 grams (g) per day. However, L-arginine supplements have been shown to be safe to take in oral doses ranging from 1.5 to 24 g daily for up to 18 months. You can also follow the dosing instructions provided on the product’s label.
Optimal dosages may vary based on age, certain conditions, and the reason for supplementation. Speak with your healthcare provider to discuss which amount of L-arginine supplementation may be best for you.
Oral L-arginine is considered safe when taken in the appropriate amounts for up to 18 months.
The amino acid may be safe to take during pregnancy when consumed in low doses for a short duration. However, it’s best to speak to a healthcare provider before starting a new supplement while pregnant.
People who are breastfeeding should avoid the use of L-arginine since there is not enough research to know if it’s safe for this population.
Those who have high blood pressure or a higher risk for heart disease should also not take animal-derived L-arginine supplements. Research has shown the supplement could potentially worsen risk factors for these conditions.
Potential Drug Interactions
L-arginine may interact with certain medications, including:
- Antihypertensive medications: Since L-arginine may lower blood pressure, combining the supplement with any blood pressure medication may lead to blood pressure levels that are too low (hypotension).
- Diuretics: Taking L-arginine along with potassium-sparing diuretics could potentially increase the risk of dangerously high potassium levels in the blood (hyperkalemia).
- Blood thinners: When taken with anticoagulant medications, L-arginine may increase the risk of excessive bleeding or bruising.
- Nitrates: The body converts L-arginine into nitric oxide which widens blood vessels, so taking the supplement with nitrate medications—vasodilators often used for angina and other heart conditions—may increase the effect.
- Diabetes drugs: L-arginine may lower blood sugar levels, so combining the supplement with diabetes drugs, including insulin, could increase the risk of too-low levels of glucose in the blood (hypoglycemia).
For the same reasons, L-arginine may also interact with certain supplements or herbs, including those that help lower:
- Blood pressure, such as niacin or stinging nettles
- Clotting risk, such as garlic, ginger, or gingko
- Blood glucose levels, such as cinnamon, chromium, or bitter melon
What to Look For
The U.S. Food and Drug Administration (FDA) does not regulate supplements in the same way they regulate food and drugs. When purchasing a supplement, look for brands that have undergone third-party testing.
These products will have seals of the third-party testing organization on the bottle. For example, the National Sanitation Foundation (NSF) and the U.S. Pharmacopeia (USP) are two groups that assess supplements for purity and quality.
Can You Take Too Much L-Arginine?
There is currently no set upper intake level for L-arginine. Clinical research has examined the use of L-arginine in doses of up to 24 g per day. Taking over 30 g of L-arginine may be potentially unsafe.
If you have questions about a safe dosage of a supplement for you, talk to your healthcare provider.
Side Effects of L-Arginine
Although L-arginine is generally well tolerated, some people may experience adverse reactions to the supplement. The most common side effects of L-arginine supplementation include:
- Abdominal pain
- Abdominal distention or bloating
- Nausea
- Diarrhea
- Low blood pressure
- Headaches
- Flushing
- Insomnia
Speak to a healthcare provider if you experience any adverse reactions from taking L-arginine.
L-arginine is an amino acid the body naturally creates, but it can also be found in protein-rich foods. It’s also possible to supplement with L-arginine. Research suggests L-arginine supplementation may be beneficial in the management of conditions like hypertension and erectile dysfunction.
Although L-arginine is typically well tolerated, side effects like gastrointestinal discomfort and low blood pressure are possible. Always speak to your healthcare provider before integrating a new supplement to determine what form and dosage may be right for you.
