What Is L-Citrulline?
L-Citrulline is a naturally occurring amino acid found in watermelon and produced by the body. It is best known for increasing nitric oxide (NO) levels, improving blood flow, enhancing exercise performance, and supporting recovery.
It is one of the most effective supplements for pump, endurance, and circulation, and is commonly used in pre-workout formulas — though pure L-citrulline works better than most blends.
How L-Citrulline Works (Science)
✔ Boosts Nitric Oxide (NO) Production
L-citrulline converts into L-arginine, which then boosts nitric oxide — a molecule that widens blood vessels.
Higher NO levels lead to:
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better blood flow
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improved oxygen delivery
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stronger pump
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enhanced nutrient transport
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better endurance
✔ More Effective Than L-Arginine Itself
Surprisingly, L-citrulline increases blood arginine levels more than L-arginine supplements.
This is because L-arginine gets largely broken down in the digestive tract, while L-citrulline bypasses this and converts efficiently.
✔ Reduces Muscle Fatigue
By improving circulation and clearing ammonia/lactate, L-citrulline supports:
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more reps
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more sets
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better performance under fatigue
✔ Supports Cardiovascular Health
Some research shows improved:
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endothelial function
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blood pressure
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circulation
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heart health markers
✔ Increases ATP Production
L-citrulline may support mitochondrial function, contributing to better energy output during training.
Benefits of L-Citrulline
1. Bigger, Longer-Lasting Pumps
One of the most noticeable effects. Improved blood flow leads to:
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fuller muscles
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stronger mind–muscle connection
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enhanced training motivation
2. Better Strength & Endurance
Studies show L-citrulline can increase:
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total reps
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training volume
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time to exhaustion
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overall power output
3. Faster Recovery
Improved blood flow enhances nutrient delivery and waste removal → better recovery.
4. Better Circulation (Daily Use)
Useful for people with:
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cold hands/feet
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poor blood flow
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cardiovascular concerns (always consult your doctor)
5. Sexual Health Support
Because it increases blood flow, L-citrulline may support erectile function by enhancing nitric oxide — similar mechanism as popular medications but much milder.
L-Citrulline vs. Citrulline Malate
Citrulline malate = citrulline + malic acid
Often appears as 2:1 ratio (2g citrulline per 1g malate).
Which is better?
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Pure L-citrulline → best for pumps + NO boost
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Citrulline malate → slightly better endurance due to malate
However, many supplements underdose malate or use fake ratios.
For consistency, pure L-citrulline is more reliable.
Ideal L-Citrulline Dosage
⭐ For performance & pumps:
6–8 grams L-citrulline (taken 30–60 minutes pre-workout)
⭐ For circulation (daily use):
3–6 grams daily
⭐ For sexual health:
2–3 grams daily, split doses
⭐ Best timing
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Pre-workout: 30–60 minutes before training
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Daily circulation: Morning or split doses
Important:
Do not confuse L-citrulline with:
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“Citrulline complex”
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“Citrulline blend”
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Under-dosed pre-workout formulas
Pure citrulline is the most reliable option.
Safety & Side Effects
L-citrulline is extremely safe for most healthy adults.
Possible mild effects:
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stomach fullness
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warm feeling / pump sensation
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increased blood flow (normal)
Avoid combining with:
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nitrates (certain blood pressure meds)
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PDE5 inhibitors (Viagra/Cialis) unless doctor approves, as effects may stack
No known long-term negative effects at standard dosages.
Best Stacks With L-Citrulline
✔ Beta-Alanine (2–4 g daily)
Improves endurance, pairs well pre-workout.
✔ Creatine Monohydrate (3–5 g daily)
Strength + power + volume → great synergy.
✔ L-Tyrosine (500–1000 mg)
Enhances focus during high-intensity training.
✔ Electrolytes (sodium + potassium)
Better pumps + hydration.
✔ Magnesium Glycinate
Supports relaxation, recovery, and better muscle function.
Who Should Use L-Citrulline?
Ideal for:
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Lifters who want stronger pumps
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Athletes needing more endurance
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People wanting better recovery
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Those with circulation issues
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Anyone wanting improved sexual blood flow
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Pre-workout users who want a clean, proven ingredient
Summary
L-citrulline is one of the most effective, science-backed supplements for improving blood flow, boosting pumps, enhancing endurance, and supporting recovery. It is safe, well-tolerated, and highly reliable when taken in the correct dosages.
If you want a no-nonsense, research-backed pre-workout ingredient — L-citrulline should be at the top of your list.
VerifiedSupps Medical Disclaimer
Disclaimer:
This content is for informational and educational purposes only and is not medical advice. Supplements affect everyone differently. Always talk with your doctor or healthcare provider before starting any new supplement, especially if you have a medical condition, are taking medication, or are pregnant or breastfeeding.