L-Citrulline is a well-known pre-workout ingredient believed to increase nitric oxide levels, improve blood flow, and enhance workout performance. But does it live up to the hype? A recent study (1) takes a closer look at the effects of L-Citrulline supplementation on strength, endurance, and muscle oxygenation. Let’s dive into what the researchers found.

How the Study Was Conducted

Researchers aimed to test L-Citrulline’s effectiveness before resistance training. Here’s a breakdown of what they did:

  • Participants: 18 resistance-trained men and women
  • Supplementation: Each participant took 8 grams of L-Citrulline or a placebo one hour before training.
  • Study Design: A crossover approach where participants experienced both the L-Citrulline and placebo conditions.

Once in the gym, the participants completed three key performance tests:

  1. Isometric Mid-Thigh Pull: Measures force output in a static position.
  2. Ballistic Bench Press: Two sets of two reps at 75% of their 1-rep max, measuring explosive power.
  3. Strength-Endurance Bench Press: A 5-rep max at 75% of their 1-rep max, assessing total volume and muscle oxygenation.

Additionally, the researchers tracked subjective factors, including energy levels, focus, fatigue, and muscle pump.

The Surprising Results

Despite L-Citrulline’s claims, the study revealed no significant improvements for participants who took the supplement compared to the placebo group:

  • Force Output: In the mid-thigh pull, results were identical for both groups.
  • Explosive Power: Barbell velocity and power during the bench press showed no improvement.
  • Strength-Endurance: Both groups completed nearly the same number of reps.
  • Muscle Oxygenation: No measurable differences were observed.
  • Subjective Factors: Fatigue levels were slightly higher for women, but this was unrelated to L-Citrulline.

What Does This Mean for Your Workouts?

Based on this study, a single 8-gram dose of L-Citrulline did not improve strength, endurance, or muscle oxygenation during resistance training.

However, this doesn’t completely rule out L-Citrulline as a performance enhancer. More research is needed to determine if:

  1. Higher doses might be more effective.
  2. Long-term supplementation provides cumulative benefits.

For now, if you’re considering L-Citrulline for your workouts, it may not deliver the dramatic results that supplement companies promise.

Final Thoughts

L-Citrulline is a popular ingredient, but this study highlights the importance of evidence-based supplementation. Not every pre-workout claim holds up under scrutiny, and this research serves as a valuable reminder to focus on proven strategies for enhancing resistance training.

References

  1. Gonzalez AM, Yang Y, Mangine GT, Pinzone AG, Ghigiarelli JJ, Sell KM. Acute Effect of L-Citrulline Supplementation on Resistance Exercise Performance and Muscle Oxygenation in Recreationally Resistance Trained Men and Women. Journal of Functional Morphology and Kinesiology. 2023;8(3):88.
  2. Gonzalez AM, Townsend JR, Pinzone AG, Hoffman JR. Supplementation with nitric oxide precursors for strength performance: A review of the current literature. Nutrients. 2023;15(3):660.

Key Takeaways:

  • L-Citrulline did not significantly improve resistance training performance in this study.
  • The supplement showed no measurable effects on force output, endurance, or muscle oxygenation.
  • More research is needed on dosage and long-term use.