L-Citrulline for Pump and Performance: Updated Research

L-Citrulline for Pump and Performance: Updated Research

Ask any strength training enthusiast what creates a good pump, and you will likely hear "arginine." But science says something surprising: L-citrulline is actually a better way to raise plasma arginine levels than supplementing arginine directly. This paradox has reshaped pre-workout formulations worldwide.

Why Citrulline, Not Arginine?

Schwedhelm et al. (2008) demonstrated clearly in their study: orally administered L-citrulline raises plasma L-arginine levels more effectively than the same amount of L-arginine. The reason is pharmacokinetic:

• L-arginine is largely degraded in the digestive tract and liver (first-pass effect) before reaching systemic circulation
• L-citrulline passes through the digestive tract virtually intact and is converted to L-arginine in the kidneys
• Result: more arginine actually reaches tissues where it is needed

This is why modern pre-workout products have largely replaced arginine with citrulline.

The Nitric Oxide Pathway

L-citrulline's primary effect is based on increasing nitric oxide (NO) production:

1. L-citrulline → converted in kidneys → L-arginine
2. L-arginine → NO synthase enzyme → nitric oxide (NO)
3. NO → smooth muscle relaxation in blood vessels → vasodilation (blood vessel widening)

Vasodilation means:

• Greater blood flow to muscles
• Better nutrient and oxygen delivery
• More efficient waste product removal
• That tangible "pump" feeling during training

Pérez-Guisado & Jakeman 2010: Reps to Failure

One of the most influential citrulline studies was conducted by Pérez-Guisado and Jakeman (2010):

• 41 men received either 8g citrulline malate or placebo before bench press
• Result: the citrulline malate group performed significantly more reps to failure
• The effect increased with set number — the difference in sets 3–8 was greater than in sets 1–2
• 73% of subjects reported less muscle soreness 24–48 hours post-workout with citrulline

This study showed citrulline malate does not just improve first-set performance but helps maintain performance across multiple sets — highly relevant in strength training.

Glenn et al. 2017: Cycling Performance

Glenn et al. (2017) examined citrulline's effects on high-intensity cycling:

• Subjects received 8g L-citrulline or placebo
• Result: improved high-intensity cycling performance
• Especially improved efforts lasting 1–6 minutes
• The effect was consistent with NO-mediated vasodilation

This study expanded citrulline's evidence base from strength training into endurance disciplines.

Dosing

L-Citrulline vs Citrulline Malate

An important distinction:

• L-citrulline — pure citrulline. Effective dose: 3–6g
• Citrulline malate — citrulline + malic acid. Typically 2:1 ratio. Effective dose: 6–8g (contains ~4–5.3g citrulline)

Most studies have used citrulline malate, but pure L-citrulline is equally effective at a lower dose.

Practical guide

• Pre-workout: 6–8g citrulline malate OR 3–5g pure L-citrulline, 30–60 minutes before training
• Timing matters: citrulline needs time to absorb — 30–60 minutes pre-workout is optimal
• Empty stomach: better absorption, but take with light food if you experience GI sensitivity
• Daily intake: some research suggests consistent daily intake is more effective than training-day-only use

Combining With Other Supplements

L-citrulline is often a core component of pre-workout formulas. It combines well with:

• Beta-alanine — citrulline improves blood flow, beta-alanine buffers acidity → complementary effects
• Caffeine — cognitive and energetic support + vasodilation
• Creatine monohydrate — ATP and blood flow combo synergy

Find L-citrulline products and pre-workout supplements at MaxFit.ee.

Safety and Side Effects

L-citrulline is generally well tolerated:

• GI discomfort is rare and usually related to large doses
• Drug interactions are poorly documented, but those on blood pressure medication should consult a doctor (NO's effect on blood pressure)
• Insufficient data for pregnant and breastfeeding women — avoid

Summary

• L-citrulline raises plasma arginine more effectively than arginine itself (Schwedhelm et al. 2008)
• Increases nitric oxide (NO) production → vasodilation → better blood flow to muscles
• Pérez-Guisado & Jakeman (2010): 8g citrulline malate improved reps to failure
• Glenn et al. (2017): improved high-intensity cycling performance
• Dose: 6–8g citrulline malate or 3–5g pure L-citrulline, 30–60 min before training
• Combines well with beta-alanine, caffeine, and creatine

References

• Schwedhelm, E., Maas, R., Freese, R., Jung, D., Lukacs, Z., Jambrecina, A., Spickler, W., Schulze, F., & Böger, R. H. (2008). Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine. British Journal of Clinical Pharmacology, 65(1), 51–59.
• Pérez-Guisado, J., & Jakeman, P. M. (2010). Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. Journal of Strength and Conditioning Research, 24(5), 1215–1222.
• Glenn, J. M., Gray, M., Wethington, L. N., Stone, M. S., Stewart, R. W., & Moyen, N. E. (2017). Acute citrulline malate supplementation improves upper- and lower-body submaximal weightlifting exercise performance in resistance-trained females. European Journal of Nutrition, 56(2), 775–784.
• Bailey, S. J., Blackwell, J. R., Lord, T., Vanhatalo, A., Winyard, P. G., & Jones, A. M. (2015). L-citrulline supplementation improves O2 uptake kinetics and high-intensity exercise performance in humans. Journal of Applied Physiology, 119(4), 385–395.

Dietary supplements are not a substitute for a varied, balanced diet and healthy lifestyle.

Browse our L-citrulline selection and pre-workout supplements at MaxFit.ee