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Want to take your athletic performance to the next level? Here's why athletes and fitness buffs are turning to L-arginine for that extra edge
Summary
1How can L-arginine help with endurance?
Before we get into it, it’s important to note that research to support L-arginine as a performance enhancer is still limited with conflicting results…
2What does the research say?
Several of the below studies have investigated whether L-arginine could significantly improve endurance…
3Should you take L-arginine for endurance?
Your decision to add L-arginine supplements to your daily routine depends on your goals and fitness level…
Many people turn to supplements to help them go that extra mile. One such supplement that’s gaining popularity in terms of athletic performance is L-arginine – an amino acid – one of the molecules that make up the proteins in your body.1-3
But could L-arginine really improve endurance, and should you consider adding L-arginine supplements to your daily routine? Let’s dig deeper and find out.
How can L-arginine help with endurance?
Before we get into it, it’s important to note that research to support L-arginine as a performance enhancer is still limited with conflicting results.4
L-arginine’s main claim to fame lies in its ability to help produce NO (nitric oxide).5 However, it’s worth noting that supplementing L-arginine doesn’t necessarily mean more NO.
Some researchers believe that in supporting NO production, L-arginine may positively impact endurance in the following ways:1,4,6
- may improve blood flow: NO relaxes blood vessels and improves circulation, a process known as vasodilation. Vasodilation allows blood to flow more freely, delivering oxygen and nutrients to your muscles during exercise
- may enhance oxygen delivery: by improving circulation, more oxygen gets to working muscles
- may improve waste removal: increased blood flow may also help remove waste products, such as lactic acid, from your muscles, allowing you to push harder for longer
- could aid in energy production: L-arginine helps produce creatine, a compound essential for energy production during high-intensity activities
What does the research say?
Several of the below studies have investigated whether L-arginine could significantly improve endurance.
However, these studies have resulted in mixed outcomes, finding that the possible benefits of L-arginine on endurance depend on factors such as an individual’s fitness levels or the type of exercise. Let’s look at some of the evidence.
One study involving overweight men found that L-arginine significantly reduced the strain from high-intensity interval exercise. It lowered the individual’s heart rate, improved their breathing and helped their body use oxygen more efficiently. These findings suggest that L-arginine could help make tough exercise sessions more manageable and increase endurance.8 However, this study was relatively small so these results aren’t guaranteed.7
On the flip side, a week of L-arginine supplementation didn’t improve performance in moderately trained swimmers tackling 200m time trials. These results show that short-term use may not work for everyone, particularly for athletes already used to middle-distance challenges.8
It’s worth noting that this study was only carried out with a small number of male swimmers, so the results aren’t transferable to everyone.8
In one small study, 56 male soccer players who took L-arginine for 45 days saw an increase in their VO2 max, a measure of aerobic capacity. This improved oxygen efficiency could translate to better endurance, helping the players to push their limits.9
Although these results were positive, they can’t be applied to the general population as the test only focused on male athletes.9
However, the story isn’t as straightforward for elite athletes. A study involving elite cross-country skiers showed no significant impact on endurance or sprint performance, even when L-arginine was combined with nitrate supplements.10
This study focused on male athletes only, so again, the results can’t be applied to the general population.10
Don’t count on L-arginine if you’re aiming to boost your strength or power through weightlifting. Research suggests it doesn’t make a difference for resistance exercises such as bench presses. Its benefits appear to be more endurance-focused than supporting raw strength.11
However, studies are limited. Endurance results are inconclusive and the results for strength are clearer.
While L-arginine could improve your endurance levels – especially by making oxygen work harder for you – its benefits aren’t universal. Results seem more noticeable in individuals building their fitness than in elite athletes. As most people aren’t elite athletes, the findings aren’t transferable to the general population.
Should you take L-arginine for endurance?
Your decision to add L-arginine supplements to your daily routine depends on your goals and fitness level. If you aim to improve endurance through cardiovascular exercises, such as running or cycling, you could try L-arginine. It may help increase your stamina and delay fatigue.1
However, it’s important to remember that L-arginine isn’t a magic bullet. As with all supplements, its effectiveness may vary from person to person, and its benefit might be less noticeable for experienced athletes who have reached a high level of cardiovascular efficiency.10
If you’re new to endurance sports or want to shake up your routine, L-arginine may provide that extra push you need. Ultimately, more studies are necessary to determine when L-arginine works best, who it works for in terms of gender and age and at what dosage.
Dosage and safety
Experts consider L-arginine generally safe and well tolerated, especially when consumed through foods such as fish, chicken, nuts and tofu.4 Many people get about 4–6g of L-arginine each day by eating L-arginine–rich foods.12
Taking high doses of L-arginine may cause side effects such as nausea, vomiting and diarrhoea, so it’s always best to follow the recommended dosage on the product label.6
It’s also important to consult a healthcare professional before taking L-arginine, especially if you have any health conditions or are taking any medication, to avoid potential complications.4
The final say
L-arginine could boost endurance, thanks to its potential role in improving blood flow. Although research shows mixed results, the effectiveness of L-arginine may vary depending on your current fitness levels and the type of exercise.4
If you’re a beginner or seeking to improve your cardiovascular performance, L-arginine could offer an edge.7,9 However, if you’re at the top of your game, you might not see any improvements from using L-arginine.10
Remember, supplementation should complement – not replace – proper training and nutrition. With the right approach, L-arginine could be a valuable tool for pushing through your endurance limits.
Want to know more about L-arginine? Check out our L-arginine guide.
The advice in this article is for information only and should not replace medical care. Please check with your GP, dietitian or healthcare professional before trying any supplements, treatments or remedies. Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.
While we strive for accuracy and balance, please be aware that this article may discuss products available for purchase through Holland & Barrett. Consult a healthcare professional before making any health-related decisions.
- Viribay A, et al. Effects of arginine supplementation on athletic performance based on energy metabolism: A systematic review and meta-analysis. Nutrients. 2020;12(5):1300. https://doi.org/10.3390/nu12051300
- Lopez MJ, Mohiuddin SS. Biochemistry, essential amino acids. Treasure Island (FL): StatPearls Publishing; 2024. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557845/
- National Human Genome Research Institute. Amino acids [Internet]. [cited 2024 Sept 17]. Available from: https://www.genome.gov/genetics-glossary/Amino-Acids/
- Office of Dietary Supplements. Dietary supplements for exercise and athletic performance: Fact sheet for health professionals [Internet]. [cited 2024 Sept 17]. Available from: https://ods.od.nih.gov/factsheets/ExerciseAndAthleticPerformance-HealthProfessional/
- Wu G, et al. Role of L-arginine in nitric oxide synthesis and health in humans. Adv Exp Med Biol. 2021;1332:167–87. https://doi.org/10.1007/978-3-030-74180-8_10
- Examine. Arginine [Internet]. [cited 2024 Sept 17]. Available from: https://examine.com/supplements/arginine/
- Daraei A, et al. L-Arginine improves endurance to high-intensity interval exercises in overweight men. Int J Sport Nutr Exerc Metab. 2021;31(1):46–54. https://doi.org/10.1123/ijsnem.2020-0054
- Esen O, et al. One-week L-arginine supplementation had no effect on 200m freestyle swimming time trial in moderately-trained male swimmers. J Diet Suppl. 2023:20(5);777–87. https://doi.org/10.1080/19390211.2022.2119321
- Pahlavani N, et al. 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;71(4):544–8. https://doi.org/10.1038/ejcn.2016.266
- Sandbakk SB, et al. Effects of acute supplementation of L-arginine and nitrate on endurance and sprint performance in elite athletes. Nitric Oxide. 2015;48:10–5. https://doi.org/10.1016/j.niox.2014.10.006
- Meirelles CM, Matsuura C. Acute supplementation of L-arginine affects neither strength performance nor nitric oxide production. J Sports Med Phys Fitness. 2018;58(3). https://doi.org/10.23736/S0022-4707.16.06680-9
- Mirmiran P, et al. Dietary L-arginine intakes and the risk of metabolic syndrome: A 6-year follow-up in Tehran lipid and glucose study. Prev Nutr Food Sci. 2017;22(4):263–70. https://doi.org/10.3746/pnf.2017.22.4.263
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