L-citrulline has emerged as a popular natural supplement for enhancing athletic performance, but can it also improve sexual function? The answer is yes—this amino acid shows genuine promise for supporting erectile function and overall sexual health through its effects on blood flow. While not as powerful as pharmaceutical medications, L-citrulline offers a natural, well-tolerated option for those seeking to enhance sexual performance. This comprehensive guide examines the science, explains how it works, and provides practical guidance for safe and effective use.

What is L-Citrulline?

L-citrulline is a non-essential amino acid found naturally in foods like watermelon (hence the name—citrullus is Latin for watermelon). It’s also produced in small amounts by the body during the urea cycle, a process that removes ammonia from the bloodstream.

L-citrulline plays a crucial role in the production of nitric oxide (NO), a compound that dilates blood vessels and improves blood flow throughout the body. This mechanism is particularly relevant for sexual function, as adequate blood flow to genital tissues is essential for arousal and performance in both men and women.

Mechanism of Action in Sexual Function

Increases Nitric Oxide (NO) Production

L-citrulline is converted into L-arginine in the kidneys through a highly efficient process.

L-arginine is then converted into nitric oxide by the enzyme nitric oxide synthase (NOS), which relaxes blood vessels (vasodilation).

This increases blood flow to the genitals, which is crucial for achieving and maintaining an erection in men and for arousal and sensitivity in women.

Why L-Citrulline Over L-Arginine?

Interestingly, L-citrulline supplementation is more effective than taking L-arginine directly. When you consume L-arginine, much of it is broken down in the digestive system before it reaches circulation.

L-citrulline bypasses this first-pass metabolism and is efficiently converted to L-arginine in the kidneys, resulting in higher and more sustained blood levels of L-arginine and subsequently more nitric oxide production.

May Improve Erection Hardness

Better blood flow can result in firmer erections and improved ability to maintain them.

Some users report more sustained or spontaneous erections with regular L-citrulline supplementation.

The improved circulation also supports the health of erectile tissues over time.

Improves Endothelial Function

Healthy endothelium (the inner lining of blood vessels) is critical for good sexual function.

L-citrulline supports endothelial health by reducing oxidative stress and promoting vasodilation, helping to maintain the flexibility and responsiveness of blood vessels.

This is particularly important for men with early-stage cardiovascular issues that manifest as erectile difficulties.

Research and Evidence

1. Erectile Dysfunction (ED)

A 2011 study published in Urology found that:

  • Men with mild ED who took 1.5 grams of L-citrulline daily for 1 month saw improvements in erection hardness and frequency
  • 50% of participants reported a noticeable improvement, suggesting mild to moderate effects
  • The supplement was well-tolerated with no significant side effects

L-citrulline is less effective than Viagra (sildenafil) or other PDE5 inhibitors, but may be beneficial for men with mild ED or for those seeking a natural alternative without side effects.

A 2015 study in American Journal of Cardiology showed that L-citrulline improved erectile function in men with ED who also had cardiovascular risk factors.

2. Synergistic Use with Other Supplements

Combining L-citrulline with other ingredients like Pycnogenol (maritime pine bark extract), Panax ginseng, or pharmaceutical ED medications may enhance effectiveness.

A notable 2008 study found that L-citrulline combined with Pycnogenol restored normal erectile function in 92.5% of men with ED, compared to either supplement alone.

Some pre-workout supplements also include it for vascularity, pumps, and potential libido boost.

3. Athletic Performance Indirect Benefit

By improving blood flow, oxygen delivery, and nutrient transport to muscles, L-citrulline may indirectly enhance sexual performance, especially in men who experience fatigue-related performance issues.

Better stamina and reduced fatigue during physical activity can translate to improved sexual endurance.

4. Blood Pressure and Cardiovascular Health

Multiple studies show L-citrulline can lower blood pressure, particularly in individuals with prehypertension or hypertension.

Since cardiovascular health is closely linked to sexual function—especially erectile function—this cardiovascular benefit supports sexual health indirectly.

Dosage

For general vascular health: 1.5 – 3 grams per day

For erectile dysfunction: 1.5 – 3 grams daily (some protocols use higher doses under supervision)

For athletic and vascular performance: 6 – 8 grams (often used pre-workout)

Timing: Can be taken once daily or split into multiple doses. Some people take it 30-60 minutes before sexual activity, though consistent daily use is more effective.

Forms of L-Citrulline

L-citrulline (free form): Pure amino acid, typically requires higher doses (6-8g for performance)

Citrulline malate: L-citrulline bound to malic acid, may enhance absorption and energy production. Common in athletic supplements.

For sexual health purposes, either form works, though some prefer pure L-citrulline for targeted dosing.

Safety and Side Effects

L-citrulline is generally safe and well-tolerated, but consider:

Mild Side Effects

Stomach upset: Usually mild and can be minimized by taking with food

Heartburn: Occasional in some users

Changes in blood pressure: Generally beneficial (lowering), but monitor if you have blood pressure concerns

Interactions and Precautions

Blood pressure medications: May enhance the effects of blood pressure-lowering medications. Monitor BP and consult your doctor.

PDE5 inhibitors (Viagra, Cialis, Levitra): May enhance effects. While not typically dangerous, use caution and consult a healthcare provider.

Nitrates: Do not combine with nitrate medications used for angina, as this can cause dangerous blood pressure drops.

Always consult a healthcare provider if you have:

  • Heart conditions or cardiovascular disease
  • Low blood pressure (hypotension)
  • Recent stroke or heart attack
  • Taking ED medications or nitrates

No Serious Side Effects Reported

Unlike some supplements, L-citrulline has an excellent safety profile with no serious adverse effects reported in clinical trials at recommended doses.

Natural Sources

Watermelon is the richest natural source of L-citrulline, particularly in the white rind.

But you’d need to consume large amounts (several pounds) to match supplement dosages—impractical for most people.

Other sources include cucumbers, pumpkins, melons, and gourds, but in much smaller amounts.

Additional Health Benefits

Beyond sexual health, L-citrulline offers:

Exercise performance: Reduces fatigue, improves endurance, and enhances muscle recovery

Blood pressure: Lowers blood pressure in people with prehypertension or hypertension

Cardiovascular health: Supports healthy blood vessel function and circulation

Muscle protein synthesis: May support muscle growth and recovery

Immune function: Plays a role in immune system support

These broader health benefits make L-citrulline a worthwhile supplement even beyond sexual enhancement.

Comparing L-Citrulline to Other Options

vs. L-Arginine

L-citrulline is superior for raising L-arginine and nitric oxide levels due to better absorption and bioavailability.

vs. Viagra/PDE5 Inhibitors

Pharmaceutical ED drugs are much more potent and work quickly (within 30-60 minutes).

L-citrulline is milder, works more gradually, has fewer side effects, and supports overall vascular health.

Best for mild ED or as a preventive/supportive measure rather than treatment for severe ED.

vs. Other Natural Supplements

Works well in combination with Pycnogenol, ginseng, maca, or horny goat weed for enhanced effects.

Who Should Consider L-Citrulline?

  • Men with mild erectile dysfunction
  • Those seeking a natural alternative to pharmaceutical ED medications
  • Individuals with cardiovascular risk factors affecting sexual function
  • Anyone looking to support vascular health and blood flow
  • Men experiencing performance anxiety or fatigue-related sexual issues
  • Athletes wanting improved performance both in and out of the gym

Summary

Benefit: Improved blood flow through [increase](/2025-07-05-do-eggs-increase-sexual-power/)d nitric oxide production Evidence: Strong scientific support

Benefit: Mild improvement in erectile dysfunction Evidence: Moderate to strong evidence in mild ED

Benefit: Increased stamina and performance Evidence: Indirect support from athletic performance studies

Benefit: Libido/desire enhancement Evidence: Anecdotal and indirect

Supporting a Comprehensive Approach

While L-citrulline can improve sexual power, particularly for men with mild erectile dysfunction or reduced blood flow, it works best as part of a holistic approach:

  • Healthy diet rich in fruits, vegetables, whole grains, and lean proteins
  • Regular exercise (especially cardiovascular and strength training)
  • Adequate sleep (7-9 hours per night)
  • Stress management through mindfulness, meditation, or therapy
  • Avoid smoking and limit alcohol consumption
  • Maintain healthy weight and metabolic health

Bottom Line

L-citrulline may improve sexual power, particularly for men with mild erectile dysfunction or reduced blood flow. It’s not a cure-all, but it can be part of a natural approach to better sexual health—especially when combined with healthy lifestyle practices including diet, exercise, sleep, and stress management.

The supplement’s excellent safety profile, affordability, and additional cardiovascular benefits make it an attractive option for those seeking natural support for sexual function. For best results, use consistently over time rather than expecting immediate dramatic effects, and consider combining with other evidence-based natural approaches for optimal sexual health.

Frequently Asked Questions (FAQ)

Q: Is this information scientifically verified?

A: Yes, the information presented is based on scientific research and medical studies. However, individual results may vary.

Q: Should I consult a doctor before trying these remedies?

A: Yes, it’s always recommended to consult with a healthcare professional, especially if you have pre-existing conditions or are taking medications.

Q: How long before I see results?

A: Results typically vary from 2-12 weeks depending on the method and individual factors. Consistency is key.

Conclusion

This article provides evidence-based information to help you make informed decisions. Remember that individual results may vary, and professional medical advice is always recommended for serious conditions.

Disclaimer: This article is for informational purposes only. Please consult with a qualified healthcare provider for medical advice.