Skip to main content

Best L-Arginine Supplements | Benefits, Dosage & Side Effects

Best L-Arginine Supplements | Benefits, Dosage & Side Effects
Claire Muszalski
Registered Dietitian3 years ago
View Claire Muszalski's profile
This is one of the lesser-known supplements, so you might be questioning "what is L-arginine?".

L-arginine is one of the twenty amino acids that make up the proteins in our body. It’s considered a “non-essential amino acid”, meaning our body can make its own without having to obtain it from food.1 It’s common in many protein food sources, like red meat, fish, chicken, dairy products, nuts, and whole grains.1 However, the wide availability of L-arginine in food sources doesn’t mean that our bodies can’t benefit from additional supplementation.

What does L-arginine do?

L-arginine plays a role in immune function, energy, and hormone regulation.2 Its supplementation has long been shown to speed up the healing process for injuries such as burns.3 That’s because L-arginine is associated with increasing white blood cell (lymphocyte) production, which helps the body to fight infection and injury.3

It’s also the precursor for nitric oxide, which is responsible for vasodilation — the relaxing and expanding of blood vessels, which helps to distribute oxygen more efficiently throughout the body.1 It’s this role as a nitric oxide precursor that makes L-arginine such an important amino acid for athletes, by improving cardio efficiency and muscle power.

Nitric oxide impacts performance in several different ways. It helps to stimulate glucose (energy) uptake in the muscles, while also burning fat.3 It enhances the action of both hormones involved in burning fat for energy and insulin, which is responsible for helping your body use the energy you get from food.3

Another important role of L-arginine is its impact on human growth hormone. Typically, growth hormone is released by the body in response to exercise (which helps with muscle-building), but research shows that supplementing L-arginine increases this response.2 Growth hormone is just one of many hormones impacted. Arginine has also been shown to have a positive impact on improving the action of insulin, which helps energy (glucose) get into your cells.3


Types of arginine

L-arginine supplements come in several forms: 

Isolated or free form L-arginine: This type mimics the way L-arginine is found in foods. 

L-arginine HCl: Bound to hydrogen chloride, which is used for many medicines and supplements to maintain a neutral pH and assist with flavour 

L-arginine Alpha Ketoglutarate: Combined with a substance that is part of the energy producing process (alpha ketoglutarate), this form is made specifically for improving performance. 


What is the best L-arginine supplement?

When it comes to choosing the “best” L-arginine supplement, you must consider what’s most important to you. 

If you want to find one that's more affordable, it’s likely to be less concentrated. If you want to find one that’s convenient, a pill or capsule form may be best. If you want to target performance improvement, the best form is AAKG (Arginine Alpha ketoglutarate). Finding a supplement with 2:1 Arginine to Alphaketoglutarate is an ideal ratio to boost your performance in the gym.  


L-arginine benefits

The benefits of L-arginine are related to its impact on nitric oxide production and hormone regulation.

1. Vasodilation

The vasodilation effect of L-arginine supplementation can increase blood flow throughout the body. This leads to better transportation of oxygen to organs and muscles, optimising the way your body responds to your workout demands.4


2. Performance and Recovery

More efficient oxygen and nutrient flow can impact your performance in several ways. Your muscles may take longer to fatigue (with better delivery of oxygen), your power may increase, and you could recover from your workout more quickly.


3. Fat Loss

There have also been studies showing the impact of L-arginine supplements on reducing belly fat.5

Belly fat, also known as visceral fat, is linked to many health problems that are linked to being overweight. A supplement that can target this specific type of stubborn fat could be very beneficial for anyone struggling with reducing their waist size.

Nitric oxide, produced from L-arginine, plays a role in glucose and glycogen uptake and fat burning. Combined with the hormonal controlling properties of L-arginine, nitric oxide can positively impact body composition in the long term.5


4. Anti-Ageing

Due to the various benefits of L-arginine in wound healing, hormonal impact, and body composition, some consider it to be an anti-aging supplement.3 The impacts of L-arginine supplements show both preventive and healing effects of many ailments related to aging.

Learn more about supplements for muscle gain and fat loss here...


Who are L-arginine supplements for?

L-arginine supplements can benefit almost everyone, based on their health and fitness goals. Aging potential  

Due to its ability to improve the delivery of oxygen and nutrients to your muscles, it can be useful for all forms of sport and exercise. Runners and cyclists can benefit from the increased oxygen delivery in cardio-based training, and body builders can benefit from the oxygen and nutrient delivery to their muscles.6

One study showed greater benefits for beginner or intermediate athletes supplementing with L-arginine than advanced, highly trained athletes  making this a worthwhile supplement for beginners.7

As previously discussed, those who are struggling with belly fat may also benefit from L-arginine supplementation, along with healthy lifestyle changes to diet and exercise.5 Coupled with the impact of L-arginine on hormones like insulin and growth hormone, there’s potential to prevent weight-related health concerns.


L-arginine dosage and side effects

The primary study that showed the increase of growth hormone release in response to L-arginine supplementation used a dose of 5-9 grams. 

A study showing performance-enhancing benefits from supplementation used 1-3grams per day.2,6 The women in the study that supported L-arginine’s potential to reduce belly fat took 3 grams, 3 times per day.5 There were few side effects mentioned in any studies in these low range dosages. 

Intravenous (IV) administration of L-arginine in high doses was linked to some digestive side effects.

Take home message

L-arginine is an amino acid that’s commonly found in food but has powerful impacts on several health outcomes, including exercise performance, body fat, and blood flow. 

If you believe that you could benefit from better oxygen delivery to your muscles, or struggle with recovery between workouts, an arginine supplement may be worth considering as part of your daily regimen. While L-Arginine supplements come in several forms (pills, powders), the best arginine supplements for performance are those with alpha ketoglutarate, and those that offer a 2:1 ratio of arginine. 


What are the benefits of L-arginine?

The main benefits of L-arginine include vasodilation leading to better oxygen transportation, increased performance and recovery, improved fat loss and potential anti-aging properties. 

What is L-arginine?

L-arginine is one of 20 amino acids found in the body. It is considered a ‘non essential’ amino acid, meaning our bodies can make it without supplementation. 

How does L-arginine work?

L-arginine is a precursor for nitric oxide, which is responsible for vasodilation. L-arginine also helps hormone regulation and helps increase white blood cell production.

What dosage of L-arginine should I take?

Research has been carried out with a range of dosages. A study which showed increases in growth hormone release used a daily dose of 5-9 gram, whilst studies which showed performance-enhancing benefits used 1-3 grams per day.

Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you're concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

1. L-arginine. (2017, October 24). Retrieved from

2. Kanaley, J. A. (2008). Growth hormone, arginine and exercise. Current Opinion in Clinical Nutrition & Metabolic Care11(1), 50-54.

3. Gad, M. Z. (2010). Anti-aging effects of L-arginine. Journal of Advanced Research1(3), 169-177.

4. Morris, C. R., Morris Jr, S. M., Hagar, W., van Warmerdam, J., Claster, S., Kepka-Lenhart, D., … & Vichinsky, E. P. (2003). Arginine therapy: a new treatment for pulmonary hypertension in sickle cell disease?. American Journal of Respiratory and Critical Care Medicine168(1), 63-69.

5. Hurt, R. T., Ebbert, J. O., Schroeder, D. R., Croghan, I. T., Bauer, B. A., McClave, S. A., … & McClain, C. J. (2014). L-arginine for the treatment of centrally obese subjects: a pilot study. Journal of dietary supplements11(1), 40-52.

6. Camic, CL, Housh, TJ, Zuniga, JM, Hendrix, CR, Mielke, M, Johnson, GO, and Schmidt, RJ. Effects of arginine-based supplements on the physical working capacity at the fatigue threshold. J Strength Cond Res24(5): 1306-1312, 2010

7. Besco, R., Sureda, A., Tur, J. A., & Pons, A. (2012). The effect of nitric-oxide-related supplements on human performance. Sports medicine42(2), 99-117.

Claire Muszalski
Registered Dietitian
View Claire Muszalski's profile

Claire is a Registered Dietitian through the Academy of Nutrition and Dietetics and a board-certified Health and Wellness Coach through the International Consortium for Health and Wellness Coaching. She has a Bachelor of Science in Biology and a Master’s degree in Clinical Dietetics and Nutrition from the University of Pittsburgh.

Talking and writing about food and fitness is at the heart of Claire’s ethos as she loves to use her experience to help others meet their health and wellness goals.

Claire is also a certified indoor cycling instructor and loves the mental and physical boost she gets from regular runs and yoga classes. When she’s not keeping fit herself, she’s cheering on her hometown’s sports teams in Pittsburgh, or cooking for her family in the kitchen.

Find out more about Claire’s experience here.