Fact Checked
Medically reviewed by 
What is L-arginine?
L-arginine is a “conditional” amino acid found in protein foods like red meat, poultry, fish, dairy, whole grains, and beans[1].
What are Amino Acids?
There are 20 different amino acids and they are considered the building blocks of life. They are organic elements that join together to form proteins in the body.
Proteins complete various functions like repair tissue, build muscle, and aid in digestion.
There are technically 3 types:
- Essential
- Non-essential
- Conditional
Essential amino acids are just that – essential! We need to get them through our diet because our body does not make them. The 9 essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Non-essential amino acids, on the other hand, are produced by the body, but levels still need to get replenished through foods depending on the body’s state and fluctuating daily needs. The 11 non-essential amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.
Conditional amino acids are actually non-essential, but can become essential during times of stress and illness or if certain medical conditions or medications affect the body’s ability to naturally meet the body’s needs. The conditional amino acids are arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline, and serine.
Amino acids can be found in every type of food we eat – fruits, vegetables, whole grains, beans, lentils, dairy products, meat, and seafood. Eating a variety of foods every day helps you get all of the amino acids your body needs. Each amino acid is important and plays a specific role in your health, but there are a few amino acids of particular interest, like L-arginine.
Why Choose L-arginine?
L-arginine is attracting more attention because of its role in producing nitric oxide. Nitric oxide signals endothelial cell function that not only controls dilation and constriction of vessels in the heart and throughout the body, but enzymes involved in blood clotting and immune function as well.
Benefits
The top 5 and most scientifically supported benefits of taking L-arginine include:
1. Lowering blood pressure[7] in healthy individuals and those with high blood pressure, as detailed in our Juvenon Blood Flow-7 review article.
2. Treating and potentially preventing pre-eclampsia (high blood pressure and protein in urine) in pregnant women
3. Improving chest pain (angina)
4. Improving erectile dysfunction
5. Increasing blood flow in those with the peripheral arterial disease (PAD – a circulatory issue that reduces blood flow to limbs and causes pain)
Potential Side Effects
L-arginine is typically taken short-term and is generally well-tolerated, but side effects may include bloating, abdominal pain, diarrhea, gout flare-ups, and could induce an allergic response, swelling your airways or worsening asthma symptoms[8].
Considerations & Takeaway
It is challenging to distinguish which benefits of supplementing L-arginine are a result of correcting an already present L-arginine deficiency or are a result of taking additional L-arginine on top of an already sufficient level in the body. There is also some controversy about the safety of taking L-arginine long-term, like discussed in one study here. This particular study found L-arginine can be beneficial or harmful to your body’s cells depending on how long you supplement. The amount of L-arginine supplemented may also make a difference.
Although L-arginine may be beneficial for some individuals, like with any type of supplement, it is important to consult your doctor first prior to starting it to review the need for it and safety of it. Supplementing this amino acid may improve or worsen certain medical conditions and interact with current medications, herbs, or other supplements you are using.
Remember, L-arginine is just ONE of the 20 amino acids! Each amino acid plays a role in your health. Consuming a variety of foods that contain all of the amino acids should be your first step to improving your health before supplementing.
Frequently Asked Questions
Q: How can you supplement L-arginine?
A: L-arginine is most commonly taken by mouth, but can also be inhaled, received through a shot, or applied to the skin.
Q: Are there are any additional benefits to supplementing L-arginine?
A: Besides the top 5 most supported benefits to using L-arginine, there is controversy or a limited amount of scientific evidence supporting other benefits. Some studies have found L-arginine may: improve exercise performance, slow blood clotting, increase potassium levels, and be protective against stomach ulcers.
This amino acid has also shown some promise in shortening hospital stays for surgical patients and reducing the number of hospital-acquired infections. In a few cases, L-arginine has prevented necrotizing enterocolitis in premature infants, which is a nasty disease that damages and can kill intestinal tissue.
Lastly, some research is finding L-arginine can lower blood sugar levels and could be a potential therapeutic aid to help treat various cardiovascular and metabolic disorders like vascular inflammation and Diabetes.[3][4][5]
Q: What are common doses of L-arginine supplementation?
A: Recommended doses will vary per individual and condition. Common doses used in research[8] even vary significantly, for example:
- Blood Pressure: 4-24 grams daily for 2-24 weeks
- Pre-eclampsia: 3-4 grams daily for up to 12 weeks or until delivery OR specific food items with 6-7 grams of arginine starting at 14 weeks pregnant until delivery
- Chest Pain: 2-6 grams – 3x/day for up to 1 month
- Erectile Dysfunction: Up to 5 grams per day, stop date varies
- Peripheral Arterial Disease: 6-24 grams daily up to 8 weeks
Q: Are there potential medication interactions?
A: L-arginine appears to lower blood pressure and could lower blood sugar levels, so taking any medications that already lower either one should be closely monitored. L-arginine may also interact with blood clotting medication and potassium-sparing diuretics by slowing clotting and increasing potassium levels in the body.
Q: Are there potential interactions with herbs or supplements?
A: Yes, L-arginine should be taken with caution if already using any herb or supplement that lowers blood pressure or blood sugar or slows blood clotting.[8]
Q: Where can I buy L-arginine?
A: You can buy L-arginine almost anywhere – from your local grocery store to your local supplement shop like GNC, as well as online through Amazon. Several places sell L-arginine in various amounts and some brands are purer than others depending on manufacturing processes, certifications, and if they additionally complete third-party testing for quality and safety assurance.
9 Sources
Health Insiders uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
[1] L-arginine. Natural Medicines - Mayoclinic https://www.mayoclinic.org/drugs-supplements-l-arginine/art-20364681Accessed Oct. 24, 2017
[2] Amino acids https://medlineplus.gov/ency/article/002222.htm
[3] Characterization of the Role of Nitric Oxide and its Clinical Applications Bradley Levine A. Levine A.B.a Punihaole D.b Levine T.B.a https://www.karger.com/Article/Fulltext/338150
[4] L-arginine | WebMD https://www.webmd.com/vitamins/ai/ingredientmono-875/l-arginine
[5] Pahlavani N, Entezari MH, Nasiri M, Miri A, Rezaie M, Bagheri-Bidakhavidi M, Sadeghi O. The effect of l-arginine supplementation on body composition and performance in male athletes: a double-blinded randomized clinical trial. Eur J Clin Nutr. 2017 Apr;71(4):544-548. doi: 10.1038/ejcn.2016.266. Epub 2017 Jan 25. Erratum in: Eur J Clin Nutr. 2017 Aug;71(8):1028. PMID: 28120856
[6] McRae MP. Therapeutic Benefits of l-Arginine: An Umbrella Review of Meta-analyses. J Chiropr Med. 2016;15(3):184-189. doi:10.1016/j.jcm.2016.06.002
[7] Journal of Advanced Research Volume 1 Anti-aging effects of l-arginine Mohamed Z.Gad doi.org/10.1016/j.jare.2010.05.001 https://www.sciencedirect.com/science/article/pii/S2090123210000573
[8] L-Arginine Overview https://medlineplus.gov/druginfo/natural/875.html
[9] Xiong Y, Fru MF, Yu Y, Montani JP, Ming XF, Yang Z. Long term exposure to L-arginine accelerates endothelial cell senescence through arginase-II and S6K1 signaling. Aging (Albany NY). 2014;6(5):369-379. doi:10.18632/aging.100663
This article changed my life!
This article was informative.
I have a medical question.
Ask a Question
This article contains incorrect information.
This article doesn’t have the information I’m looking for.