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Best Time to Take L-Arginine: Does Timing Matter?

Reviewed by: Jacek Szymanowski (Certified Nutritionist, S&C specialist, M.Sc.Eng. Biotechnology)

Research surrounding L-Arginine is somewhat conflicting, although it may have a moderate effect on aerobic and anaerobic performance. For acute effects, taking the supplement between 60-90 minutes before exercise is likely ideal, although chronic ingestion would be best for long term effectiveness.

Overall, L-Arginine is unlikely to make a major difference in your training. You may be better off using a high-quality Citrulline supplement.

What’s the best time to take L-Arginine? Arginine may produce some acute effects on aerobic and anaerobic performance when taken in high doses of ~10-11g around 60-90 minutes before exercise. Overall,while these doses are a general recommendation it’s difficult to say how different individuals will respond.

when to take l-arginine

Arginine and Athletic Performance – What We Can Expect

L-Arginine is mainly thought to work based on its role in NO production and how it may increase blood flow and vasodilation. However, there is some conflicting evidence surrounding the use of L-Arginine supplementation. Below we’ll be taking a closer look at L-Arginine’s potential effects on performance.

Enhanced Performance

Several studies show that L-Arginine supplementation has no effect on athletic performance. This includes one study measuring long-term supplementation of 2.8-5.7g/day of arginine for 4 weeks, and another measuring short-term supplementation of 6g/day for 3 days. Both studies found L-Arginine to have no effect on exercise performance. 

However, a more in-depth meta-analysis found that Arginine supplementation had some benefits to both anaerobic and aerobic performance. While this analysis included multiple studies that produced minimal results, there were several that found arginine supplementation to be beneficial. 

Drinking electrolytes during workout

Anaerobic and aerobic benefits were shown acutely with 10-11g taken 60-90 minutes before exercise, as well as equivalent chronic doses after 8 weeks. Aerobic benefits were shown with lower chronic doses of 1-3g/day for 4-7 weeks, although stronger effects may appear with larger daily doses of 10-12g/day.  

Keep in mind that such large doses are likely to cause stomach discomfort, which is a big reason why supplementation with L-Arginine likely isn’t ideal. 

Can Arginine Supplementation Be a Game Changer? 

No, while L-Arginine may have some positive effects on performance, they do appear to be fairly minor. 

Overall, L-Arginine is metabolically complicated because it is subject to extensive elimination by bacteria and different enzymes. As we’ll be covering later on, L-Citrulline is likely more effective at actually raising plasma levels of arginine, because it does not go through this same elimination, but normal systemic metabolism. 

The meta-analysis is not very clear about what the exact improvements were in the included studies. They do claim that anaerobic trials produced “small significant effects,” and that aerobic trials should be taken with caution due to publication basis. 

Still, as long as you’re taking sufficient doses (10-11g for acute effects and 1-12g/day for 4+ weeks for chronic effects), L-Arginine may be somewhat beneficial, specifically for anaerobic performance. However, this is highly unlikely to be a game changer in your training, which is why we don’t strongly recommend this supplement. 

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When to Take L-Arginine for Performance?

L-Arginine’s effects appear to be most prominent when it’s taken chronically. While doses as low as 1-3g were shown to be beneficial for aerobic performance when taken daily for 4-7 weeks, we recommend aiming for a higher dose of 10-12g/day for 8 weeks for optimal effects on both anaerobic and aerobic performance. Just keep in mind these doses are very likely to cause gastrointestinal discomfort, so it may not be worth it. 

preparing creatine drink

When to take L-Arginine for chronic supplementation wasn’t mentioned in the meta-analysis. This is because timing is generally not important when it comes to chronically dosed supplements. 

With this being said, the best time of day to take L-Arginine is likely right before your workouts in order to maximize any additional acute effects, especially if you’re taking a higher dose. So, if you’re trying to decide whether to take L-Arginine before or after your workout, we recommend going before. 

Also, there is no mention in the meta-analysis about ingesting food alongside L-Arginine. This leads us to believe that nutrient timing doesn’t have a major effect on L-Arginine supplementation, and taking L-Arginine on an empty stomach should be fine. Regardless, keep in mind that proper nutrition will likely have a much greater overall impact on your training than nearly all supplements, including L-Arginine.

L-Arginine as a Pre-Workout Supplement

If you’re planning on using L-Arginine as a pre-workout supplement, both timing and dose are important. Overall, you’re likely best off taking 10-12g/day regardless of whether you’re working out to optimize both chronic and acute effects. Still, on days you’re working out, be sure to take it around 60-90 minutes before your workout to optimize acute effects. 

You may also be wondering, “Can I take L-Arginine with pre-workout?” Because L-Arginine is a common ingredient in many pre-workout formulas, it should be fine to take an additional dose alongside your pre-workout of choice.  

L-Citrulline vs L-Arginine

One of the most similar supplements to L-Arginine is L-Citrulline because of how it also appears to increase NO production and L-Arginine bioavailability. 

A meta-analysis on Citrulline Malate (L-Citrulline bonded with Malic Acid) found that acute supplementation with 6-8g led to a small significant increase in total reps performed during weightlifting. It’s worth noting this is roughly equivalent to 4-5g of pure L-Citrulline.

athlete taking vitamins

Another individual study found that chronic supplementation with 6g/day of L-Citrulline was able to increase post-exercise reoxygenation rate, improve endurance, and lead to shorter necessary rest between sets. 

While 3g/day appears to be the minimum required amount for noticeable effects, we generally recommend chronic doses closer to 6-10g/day for optimal effects, which would be roughly 9-15g of Citrulline Malate.

For acute supplementation, you will likely want to stay within a similar range, with 3g being the bare minimum, and 6-10g likely producing more significant effects. However, as with L-Arginine, we mainly recommend taking L-Citrulline as a chronic supplement for optimal effectiveness. 

Overall, while L-Arginine does appear to have some minor benefits for anaerobic and aerobic performance, we believe L-Citrulline to be the more effective supplement for its effects on recovery and endurance. L-Citrulline is also less likely to cause gastrointestinal side effects like L-Arginine.

Below is a table offering a quick comparison of both supplements.

L-CitrullineL-Arginine
Acute Dose– 3-10g+ (9-15g of Citrulline Malate)– 10-11g for Anaerobic Effects
Chronic Dose– 3-10g+/day (9-15g of Citrulline Malate)– 1-3g/day for 4+ weeks for Aerobic effects
– 10-12g/day for 8+ weeks for Anaerobic effects
Potential Effects– Increased Endurance
– Improved Recovery
– May increase anaerobic performance
– May ncrease aerobic performance

Our Recommendation – L-Citrulline by Kaged

L-Citrulline by Kaged

l-citrulline kaged
  • Form: Powder
  • Suitable for Vegans: No
  • Servings per Container (3g): 67
  • Price per Serving: ~$0.37
  • Company Founded: 2015
  • Recommended by AthletesAndrea SomerColt NicholsKris Gethin

While L-Citrulline is included in many pre-workout formulas, it is often dosed too low to produce any meaningful effects. If you’re interested in using L-Citrulline, it may be easier to supplement it individually using a high-quality single-ingredient formula like that from Kaged

Each serving of this supplement contains 2g of L-Citrulline, which is likely not enough to produce any significant effects. You’re likely best off taking 3+ servings a day for a total of 6-10g of L-Citrulline, which will be enough to produce beneficial acute and chronic effects. At 200g per package, this will still last you ~20-33 days with daily use. 

kaged citrulline
Photo by @kaged

As mentioned, this is a high-quality single ingredients supplement, meaning it contains no unnecessary preservatives, sweeteners, or dyes. It is also third-party tested by Informed Sport, making this a great choice for any competitive athletes, and those who are concerned about contaminants in their supplements. 

Each 2g serving of Kaged’s L-Citrulline will cost you ~$0.25, which means a 6-10g serving will cost ~$0.75-$1.25. 

Conclusion

Overall, the best time to take L-Arginine for aerobic and anaerobic performance is once a day, around 60-90 minutes before your workout at a dose of 10-12g. 

With this being said, we believe the similar supplement L-Citrulline will likely be more beneficial for your training. If you’re interested in using L-Citrulline, we recommend checking out Kaged’s product.

Have you ever used either L-Citrulline or L-Arginine? Let us know your thoughts in the comments below!

Also read:

References:

  1. T. Abel, et. al, “Influence of Chronic Supplementation of Arginine Aspartate in Endurance Athletes on Performance and Substrate Metabolism” Int J Sports Med; 26(5): 344-349 (2005).
  2. Tsung-Han Liu, et. al, “No effect of short-term arginine supplementation on nitric oxide production, metabolism and performance in intermittent exercise in athletes” The Journal of Nutritional Biochemistry, Volume 20, Issue 6, 462-468 (2009).
  3. Aitor Viribay, et. al, “Effects of Arginine Supplementation on Athletic Performance Based on Energy Metabolism: A Systematic Review and Meta-Analysis” Nutrients, 12(5), 1300; (2020).
  4. Fredrik Tonstad Varvik, et. al, “Acute Effect of Citrulline Malate on Repetition Performance During Strength Training: A Systematic Review and Meta-Analysis” Int J Sport Nutr Exerc Metab. Jul 1;31(4):350-358. (2021).
  5. L. Wehrman, et. al “EFFECTS OF L-CITRULLINE SUPPLEMENTATION ON LOCALIZED BLOOD FLOW AND POST-EXERCISE MUSCLE REOXYGENATION RATE” International Journal of Exercise Science: Conference Proceedings: Vol. 8: Iss. 11, Article 10. (2023).
  6. Photos made by Torokhtiy Media Team.

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Camila Parente Santos

Author: Camila Parente Santos
Sports Nutritionist

Experience: 7 years

Camila has worked as a Nutritionist for 7 years. In addition to being a nutritionist, she is an amateur weightlifting athlete for 2 years. Camila has experience at Flamengo’s football base and in a food supplement company and currently provides services at a clinic. At the moment she is coursing a postgraduate study in Sports Nutrition.

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Jacek Szymanowski

Reviewed by: Jacek Szymanowski

Certified Nutritionist,
M.Sc.Eng. Biotechnology
Performance architect
,
Strength and Conditioning Specialist

Experience: 20 years

With over 30 years of fighting experience, specialization in nutrition coaching for athletes, and expertise in metabolic health and dietary strategies, Jacek offers a comprehensive approach to optimizing your performance and well-being. Backed by a Master of Science degree in Biotechnology, Jacek remains at the forefront of scientific advancements, ensuring that his coaching is always evidence-based and up-to-date.

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