Arginine is a conditionally essential amino acid that serves as a substrate for nitric oxide production, which is essential for regulating blood pressure (BP) and immune function. Arginine also offers benefits for heart health, blood sugar regulation, immunity, athletic performance, and erectile dysfunction. The recommended arginine dose varies based on the condition being treated, but it might not be suitable for people taking specific medications for pre-existing health conditions.
Quick Look
- L-arginine is a conditionally essential amino acid that becomes essential during times of illness and stress.
- Arginine serves as the precursor for nitric oxide (NO) synthesis, which is essential for regulating BP.
- The body requires arginine for immune function, blood glucose regulation, and enhancing athletic performance.
- The recommended arginine dosage depends on the condition being treated.
- L-arginine supplements may interact with certain medications, including blood thinners, antihypertensives, and diuretics.
Table of Contents
What Is Arginine?
L-arginine, usually shortened to arginine, is a conditionally essential amino acid—the body can produce small amounts of arginine endogenously but not in quantities sufficient to support its many functions. During illness and stress, the body’s arginine demands exceed its ability to produce it, so it must come through diet or amino acid supplements.
Although typically thought of in relation to NO production, arginine is one of the most metabolically versatile amino acids, serving as a precursor for the synthesis of several compounds, including:
- Urea
- Nitric oxide
- Polyamines
- Proline
- Glutamate
- Creatine
What Does Arginine Do?
In addition to being a proteinogenic amino acid—it contributes to protein synthesis—arginine also serves as a precursor in NO production; it’s essential for the enzyme nitric oxide synthase (NOS), which is vital for regulating BP via facilitating vasodilation and improved blood circulation.
L-arginine is also essential for stimulating the production of various hormones, including human growth hormone (hGH) and insulin, to help facilitate the entry of glucose into cells. This is one of the primary reasons arginine is used in the fitness industry.
Although proteins are involved in immune responses, the role of arginine in immunity steps away from protein-building and supports the production and behavior of immune cells.
Arginine is a substrate for specific metabolic pathways that influence immune cell biology—specifically, macrophage, dendritic cell, and T-cell immunobiology.
To sum that up, arginine is essential for:
- Healthy immune responses
- Muscle growth and recovery
- Blood glucose regulation
- BP and heart health
- Improving erectile dysfunction (ED)
Key takeaway: L-arginine is a conditionally essential proteinogenic amino acid involved in protein synthesis. It also serves as a precursor to NO synthesis, which is critical for blood pressure regulation and immunity.
Arginine Amino Acid Benefits
Although L-arginine can be produced in the body in small quantities, most people take it through a lone supplement or combined with other amino acids in an essential amino acid supplement. But why?
Here are five arginine benefits you should know about.
Reduces high blood pressure and heart health
Hypertension is a major health concern worldwide, and in 2021, it was the leading cause of nearly 700,000 deaths across the United States. High BP not only reduces the quality of life, but it drastically increases the risk of cardiovascular disease and stroke—the leading causes of death in the US.
While altering diet and lifestyle can often control BP, natural medicines or supplements like arginine may offer benefits. L-arginine is a precursor molecule for nitric oxide synthase, which produces NO.
NO is produced in vascular endothelium and is responsible for relaxing cells in smooth muscle, which is essential for regulating BP. Improving endothelial function has massive benefits for reducing the risk of cardiovascular disease.
Research shows that taking arginine supplements can reduce systolic and diastolic BP, likely via increasing blood NO levels. A 2016 review found that supplementing with L-arginine (IV and oral L-arginine) significantly reduced systolic and diastolic BP in adults with high BP by up to 5.4 mm/Hg and 3.1 mm/Hg, respectively.
Arginine has also shown promise for improving heart health. For people at risk of cardiovascular disease, specifically heart disease, arginine supplements are an effective means to prevent heart attack or stroke. Here’s how:
- Reducing blood pressure
- Improving blood flow
- Reducing cholesterol and triglyceride levels
- Helping relieve congestive heart failure
- Improves symptoms of claudication (cut-off blood flow from the heart to the limbs)
Supports immunity
Immune boosters are all the rage, but who knew something as simple as the amino acid arginine could do wonders for your immune function?
Arginine supplementation has been combined with other nutrients to boost immune function. Low arginine levels have been found in some people struggling with various illnesses, trauma, and cancer, suggesting a link between arginine and immunity.
Researchers believe that immune system suppressor cells (MSCs) may be the cause of low arginine levels or an arginine deficiency. But why does this happen? Your immune system protectors—lymphocytes and T-cells—depend on arginine for optimal function.
Enhances exercise performance
Research suggests that arginine supplementation may enhance athletic performance by boosting NO levels, which improves blood flow and oxygen delivery to active muscle tissue.
A 2017 study of 56 male soccer players found that supplementation with 2 grams of L-arginine daily for 45 days improved sports performance compared to players who didn’t take arginine.
Another study found that men who consumed a drink containing 6 grams of arginine an hour before strenuous exercise had significantly elevated blood levels of NO and had increased time to fatigue.
Here are more ways arginine may support exercise performance:
- Increase circulation to injured joints and tissues.
- Some studies suggest it improves walking distance and reduces muscle aches and pains.
- Boosts the production of human growth hormones, prolactin, and several amino acids, such as creatine, L-proline, and L-glutamate.
- Improves glucose tolerance and insulin sensitivity, similar to the results of exercise, to enhance glucose entry into cells.
- May increase time to exhaustion in athletes and increase tolerance to high-intensity activity.
- May promote benefits for bodybuilding, exercise performance, and lean muscle mass gain.
There’s also evidence to suggest that L-arginine supplementation can significantly increase growth hormone levels, which is vital for muscle growth; doses of between 5 and 9 grams have shown benefits.
Another possible mechanism is its role in creatine synthesis—arginine, glycine, and methionine are the three amino acids required for creatine synthesis. Several studies show benefits for increasing muscular strength and muscle fiber size with creatine supplementation.
Lowers blood sugar levels
For people struggling with blood sugar abnormalities—whether diagnosed as diabetic or not—L-arginine supplementation might help to improve glucose metabolism and insulin sensitivity.
Arginine is a precursor for NO production, and NO plays an essential role in cellular function and insulin response in the body. Some studies go as far as to say that L-arginine may have the potential to prevent and/or relieve type 2 diabetes through its ability to restore insulin sensitivity. As such, increasing NO may enhance the function of insulin-secreting cells and promote a healthier and more efficient blood glucose response.
Improves erectile dysfunction in men
No man wants to admit they struggle with ED, but studies suggest that the condition is more common than most people think. Some experts suggest about a third of men struggle with some form of ED, while other research suggests the global prevalence of the condition could be as high as 76.5%.
Although evidence is mixed, arginine’s role in NO production may benefit treating ED. Some research suggests that a large chunk of men who have infertility (up to 92%) can use arginine dietary supplements combined with other dilators, antioxidants, or anti-inflammatories to treat ED.
Most experts recommend 3 to 6 grams of arginine daily (split into two doses) for ED.
Key takeaway: L-arginine supplementation benefits blood pressure and heart health, immune function, athletic performance, and blood sugar. Evidence for the use of arginine in men with ED is mixed.
Arginine Recommended Dosage
Regardless of the condition you want to treat, getting the correct dose of arginine is key to achieving optimal results.
So, how much do you need?
There’s no “general” dose for L-arginine supplements to see widespread results—the recommended arginine dose depends on what condition you’re treating.
Here are some guidelines for arginine dosing:
- Blood pressure: ≥4 grams per day
- ED: 1.5 to 5 grams per day
- Pre-eclampsia: 3 to 4 grams per day for up to 12 weeks
Doses of arginine are often significantly higher in studies and clinical settings, so it’s recommended to stay at or below 9 grams per day to avoid potential GI effects. If unsure of the appropriate dose, speak to your healthcare provider before starting arginine supplementation.
Safety and Side Effects
Most studies show that L-arginine supplementation is safe and well-tolerated by most adults, regardless of supplementation length. But just because it’s a “natural supplement” produced in the body doesn’t mean this amino acid has no side effects.
While not common, some users may experience side effects from taking arginine supplements, especially in large doses, including:
- Bloating
- Abdominal pain or discomfort
- Nausea
- Diarrhea
That said, some studies show doses of up to 30 grams daily for short-term use were well tolerated without adverse effects.
However, some populations are not suited for arginine supplements. For example, people with asthma, liver cirrhosis, kidney disease, low BP, and guanidinoacetate methyltransferase deficiency should avoid arginine use.
Arginine interactions
L-arginine supplements may interact with certain medications, including:
- Blood pressure medications
- Erectile dysfunction medications
- Blood-thinners
- Antidiabetic medication
- Medications that enhance blood flow
- Diuretics
Arginine dietary supplements may also interact with natural supplements, some of which include:
- Supplements that lower blood pressure: CoQ10, cat’s claw, fish oil, Lycium, stinging nettle, theanine
- Supplements that lower blood glucose: Fenugreek, Panax ginseng, Siberian ginseng, guar gum
- Natural blood thinners: Clove, angelica, garlic, ginkgo biloba, Panax ginseng, turmeric
- Xylitol
If you’re taking medications or natural supplements, speak with your healthcare professional before starting arginine supplements.
Food Sources of Arginine
As with any other amino acid, arginine is widely available in foods if you’re not keen on supplementation.
As we said earlier, the human body naturally produces small amounts of arginine, but how much depends on various factors, including:
- Age
- Health status
- Cardiovascular health
- Gender
- Diet
- Genetics
There are several reasons arginine synthesis may be stunted in some people. The most common include:
- Low-protein diet
- Poor digestive health
- High oxidative stress levels (inflammation)
- Smoking
- Genetics
In such cases, supplementing or eating an arginine-rich diet becomes essential.
Protein-rich foods—and complete proteins derived from animal-based products—contain some of the highest arginine concentrations. Some of the best food sources of arginine are:
- Eggs
- Dairy products (choose organic and raw when possible)
- Grass-fed red meat
- Poultry
- Organ meats
- Wild-caught fish and seafood
- Pumpkin seeds
- Sesame seeds
- Sunflower seeds
- Seaweed (and other sea vegetables)
- Spirulina
- Almonds
- Walnuts
- Brazil nuts
Final Thoughts
Arginine is a conditionally essential amino acid naturally produced in small quantities in the body but becomes essential under certain conditions, such as stress and illness.
Research has shown L-arginine supplements offer benefits for cardiovascular health, immunity, exercise performance, blood sugar, and ED.
Arginine supplements are popular, but you can naturally increase arginine and NO levels by consuming high-arginine foods, such as meat, fish, and eggs, that provide arginine and the full range of essential amino acids.
Frequently Asked Questions
Is it safe to take arginine every day?
Yes, research has shown that L-arginine supplements are safe and well-tolerated by most people when taken daily for long-term use. However, the safety of L-arginine supplements depends on the condition being treated and any underlying health concerns.
Does L-arginine increase testosterone?
Some evidence suggests L-arginine supplements can enhance muscle growth and encourage fat loss via boosting creatine and growth hormone synthesis. Still, there’s little research suggesting it has a direct or indirect effect on testosterone levels.
Should I take L-citrulline or L-arginine?
L-citrulline and L-arginine are often lumped together because they are involved in similar bodily functions, namely increasing NO production. Still, some research suggests citrulline may be more effective at increasing NO levels in the bloodstream.
Which foods have the highest amounts of arginine?
High-protein foods like red meat, poultry (chicken and turkey), eggs, and dairy products contain the highest arginine levels. For example, one cup of cooked chicken contains 2.8 grams of arginine, while one pound of cooked ground beef contains 4.2 grams.
Can arginine help you sleep?
There’s little research on the direct effects of arginine on sleep, but its ability to increase blood circulation by promoting vasodilation (widen blood vessels) may offer relaxing effects conducive to sleep.
