L-Citrulline / Citrulline Malate
What is it?
L-Citrulline is a non-protein amino acid found naturally in watermelon and produced by the body in the urea cycle. Unlike Arginine, Citrulline has excellent oral bioavailability — it is converted to Arginine in the kidneys, raising plasma arginine levels more efficiently than direct Arginine supplementation. This results in greater nitric oxide production, vasodilation and improved muscular blood flow. Citrulline Malate is the combination of L-Citrulline with malic acid, which adds benefits to energy metabolism via the Krebs cycle.
Main Benefits
- Superior to Arginine for raising plasma nitric oxide
- Improved muscle pump and vasodilation
- Reduced fatigue in repeated sets
- Increased tolerated training volume
- Attenuation of DOMS (delayed onset muscle soreness)
- Citrulline Malate adds support to aerobic energy metabolism
Who it's for
- •Resistance training practitioners seeking greater pump and training volume
- •Endurance athletes needing better oxygen delivery
- •Those doing high-volume training with many sets
- •People who used Arginine and want better results
- •Practitioners of cyclic sports (cycling, swimming, running)
Common Dose
Pure L-Citrulline: 3g to 6g per dose, 30 to 60 min before training. Citrulline Malate (2:1): 6g to 8g per dose. Check the ratio on the label — 8g of Citrulline Malate 2:1 equals approximately 5.3g of pure L-Citrulline.
Available Types
Pure L-Citrulline
Characteristics
- •100% L-Citrulline without additives
- •Smaller dose required (3–6g)
- •Without the malic acid component
- •Exclusive focus on nitric oxide and vasodilation
Pros
- Smaller dose
- More economical per gram of active citrulline
- Ideal for those focused on NO2 and pump
Cons
- Without the additional benefit of malate in energy metabolism
Best for
- Strength and hypertrophy training
- Those seeking pump and vasodilation
- Use in personalized pre-workouts
Citrulline Malate (2:1)
Characteristics
- •Combination of L-Citrulline with malic acid in 2:1 ratio
- •Larger dose required (6–8g)
- •Malic acid supports the Krebs cycle and ATP production
- •Most studied form in sports context
Pros
- Dual benefit: vasodilation + energy support
- Most used form in sports studies
- May reduce DOMS more than pure citrulline
Cons
- Larger dose required
- More expensive per serving
- Slightly acidic taste
Best for
- High-volume training
- Endurance sports
- Those wanting combined pump and energy benefit
Quick Comparison
| Feature | Pure L-Citrulline | Citrulline Malate 2:1 |
|---|---|---|
| Effective dose | 3–6g | 6–8g |
| Citrulline per dose | 3–6g | 4–5.3g |
| Extra benefit | None | Energy support (malate) |
| Sports studies | Good | More abundant |
| Cost per dose | Lower | Higher |
| Best for | Strength and pump | Volume and endurance |
How to Choose
Pure L-Citrulline
Choose if:
- The focus is pump and vasodilation
- You want the smallest possible dose of active citrulline
- You are building a personalized pre-workout
Citrulline Malate (2:1)
Choose if:
- You do high-volume training with many sets
- You practice endurance sports
- You want the combined benefit of pump and energy support
What the Science Says
Citrulline is consistently superior to Arginine for raising plasma arginine levels and nitric oxide production — studies show that 6g of Citrulline Malate raise plasma arginine more than 6g of oral Arginine. Studies with Citrulline Malate show increased repetitions per set, reduced muscle fatigue and lower post-workout DOMS. Malic acid contributes to ATP resynthesis via the Krebs cycle, making the combination especially interesting for high-volume training.
Possible Side Effects
Generally well tolerated. At high doses it may cause mild gastrointestinal discomfort. The Malate version may have a slightly acidic taste. No relevant adverse effects documented at normal use doses.
Final Summary
Citrulline is the best supplement available for pump, vasodilation and increased training volume — superior to Arginine in all practical aspects. Pure L-Citrulline is ideal for strength and pump with a smaller dose. Citrulline Malate is the choice for high-volume training and endurance. Both have excellent scientific evidence and are considered among the most effective pre-workouts available.