L-Arginine: Benefits, Side Effects & Dosage

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What is L-Arginine?

L-arginine is one of many amino acids the body needs to function properly. The body produces amino acids on its own. However, essential amino acids can only come from the foods we eat. High sources of L-arginine include red meat, poultry, fish, eggs and dairy products (x). L-arginine is also created in laboratory settings and used to make supplements that benefit heart health, exercise performance, mental capabilities and much more.

Benefits of L-Arginine

As a supplement, L-arginine plays a role in building protein, which the body uses to build muscle, heal wounds and rebuild tissue (x). It helps rid the body of waste and ammonia, which causes the release of insulin. Though it may not prevent the development of type 2 diabetes, it may increase insulin sensitivity and assist with blood sugar control (x).

Helps Body Function Properly

When produced in the body, L-arginine converts into nitric oxide (NO). Nitric oxide helps blood vessels relax and improves circulation. In other words, L-arginine may improve the flow of blood through the heart (x). That being said, it may also improve the symptoms of coronary artery disease. However, L-arginine supplements are not recommended as a treatment for heart disease.

Increases Strength

When used as a supplement, L-arginine may increase strength, increase endurance and contribute to the development of muscle mass. When L-arginine is converted into nitric oxide, it plays an important role in allowing blood, nutrients and oxygen to travel to every part of your body efficiently (x). L-arginine not only improves athletic performance, but also shortens recovery time after surgery and promotes weight loss. In fact, studies have shown L-arginine actually increases metabolism and may help you reach your weight loss goals (x).

Additional Health Benefits

Enhances Athletic Performance

The reason L-arginine is so popular among bodybuilders, runners, cyclists and other athletes is because it improves athletic performance. For starters, it is a precursor to nitric oxide and functions as a vasodilator, which opens up veins and arteries so that blood can flow more freely through the body. Additionally, nitric oxide can increase the activity of AMPK, a protein that controls energy balance (x).

Another important benefit of taking L-arginine is its ability to stimulate the production of certain hormones, like human growth hormone (HGH) and insulin. Increasing growth hormone levels may help you heal. In fact, taking arginine during intense exercise appears to reliably increase growth hormone (x). This is one of the reasons it is believed to enhance physical performance, stamina and strength.

Weight Loss

Arginine can promote weight loss by burning excess fat and improving muscle mass. Many studies suggest that arginine reduces fat mass by increasing insulin activity, which manipulates hormones involved in fat metabolism (x). Arginine aids in the formation of nitric oxide, which may increase the activity of fat burning and also prevent weight gain by regulating hormones involved in fat metabolism (x,x, x).

Furthermore, L-arginine is also linked to its effects on exercise tolerance. Those who exercise to lose weight will also benefit from being able to work out for longer and thus burn more calories.

Improves Heart Health

Nitric oxide improves circulation and dilates blood vessels. Without enough nitric oxide, your risk of heart disease increases. It’s what keeps your blood pressure level within a normal range because it signals the blood vessels to relax, expand and let blood through. In fact, as we age, our ability to produce enough nitric oxide within the lining of the arteries decreases. On the positive side, though, obtaining more L-arginine can enhance nitric oxide capabilities and improve heart health (x).

Boosts Immune Function

L-arginine positively affects the central nervous and immune system functions. More importantly, nitric oxide acts as a neurotransmitter and protective agent against outside threats. It is also helpful at detoxifying the body and lowering the presence of ammonia within the blood (x).


One benefit of L-arginine is fighting disease-causing inflammation and improving immune function (x). L-arginine has been found to have substantial free radical-scavenging abilities (x). It is commonly used in combination with antioxidants like vitamin C and omega-3 fish oil supplements, helping slow the aging process and preventing many chronic diseases (x).

L-Arginine Benefits

Food Sources of L-Arginine

Everyone produces some L-arginine on their own, but how much depends on factors like your age, inflammation level, heart health, gender, diet quality and various genetic qualities. Some of the reasons one might not produce optimal levels of L-arginine include eating a plant-based or vegan diet low in complete protein sources, having poor digestive health that makes metabolizing protein difficult, high levels of oxidative stress, smoking and other genetic factors (x, x).

It’s easy to get the daily recommended intake of L-arginine if you include these healthy foods in your diet (x):

  • Turkey
  • Pork loin
  • Chicken
  • Pumpkin, sunflower and sesame seeds
  • Soybeans
  • Peanuts
  • Dairy products
  • Chickpeas
  • Almonds
  • Eggs
  • Wild-caught fish
  • Walnuts

L-Arginine Side Effects & Dosage

There is no recommended dosage for L-arginine by the Food and Drug Administration because the human body usually makes enough on its own (x).

Some athletes and bodybuilders choose to take L-arginine. The standard pre-workout dose for L-arginine is 3-6 grams (x).

To maintain elevated arginine levels throughout the day, arginine can be taken up to three times a day with a combined dose total of 15-18 grams. It is not recommended to take more than 30 grams a day of L-arginine (x, x).

Taking more than 10 grams of arginine at once can result in gastrointestinal distress and diarrhea, and taking more than 30 grams a day can worsen those side effects (x).

The Bottom Line

L-arginine is an amino acid that helps build protein in our body. Our bodies make it, but we still need to obtain it from the foods we eat, like red meat, poultry, fish, eggs and dairy products.

Research has shown L-arginine may benefit heart health, fight the effects of aging, boost exercise performance, improve immunity and help with weight loss. To naturally help your body make and use more L-arginine and nitric oxide, the focus should be on eating a diet based on whole foods, especially sources of animal protein, which provide a full range of amino acids (x).

By: Abby Urnovitz

About the author

Ryan Quigley

Graduate of Longwood University in Virginia. Part-time sports journalist covering the Vegas Golden Knights.

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