Why does citrulline raise arginine levels better than arginine itself?

Citrulline bypasses liver metabolism and is more efficiently converted into arginine in the bloodstream, resulting in higher plasma arginine levels.

Can I use both citrulline and arginine in the same formula?

Yes, formulations may combine both for synergistic effects, but stability and digestive tolerance must be considered in EU-compliant products.

What is citrulline malate and why is it popular?

Citrulline malate is citrulline bound to malic acid, improving absorption and energy metabolism, making it popular in preworkout supplements.

Which form is better for beginners?

Citrulline malate is often recommended for beginners due to its tolerability and performance benefits, while arginine may be more situational.

Are there EFSA-approved performance claims for NO boosters?

Currently, EFSA has not approved performance claims for citrulline or arginine. Formulations must rely on structure–function descriptions or combine with approved nutrients.

Is arginine nitrate legal in the EU?

Arginine nitrate is considered a Novel Food in the EU and is not authorized for use in supplements unless formally approved.

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Citrulline vs Arginine: What Delivers the Pump?

The “pump” — that vascular, full-muscle sensation athletes seek — isn’t just a cosmetic bonus. It’s tied to nitric oxide (NO) production, improved blood flow, and nutrient delivery during training.
Two amino acids dominate the NO booster market: L-citrulline and L-arginine. While both are precursors to nitric oxide, their absorption, stability, and EU compliance differ significantly.
At BF-EssE, we help brands design preworkout amino acid systems that go beyond hype — delivering real performance benefits with clean-label, EFSA-compliant claims and manufacturing stability.

How They Work: The Nitric Oxide Pathway

Both citrulline and arginine ultimately increase nitric oxide levels, but the body processes them differently.

Arginine → Direct precursor for nitric oxide synthase (NOS) enzymes
Citrulline → Converted to arginine in the kidneys → boosts plasma arginine more effectively than direct arginine supplementation

Fact: Multiple human trials show citrulline supplementation increases blood arginine levels more consistently than arginine itself, due to reduced first-pass liver metabolism.

Citrulline: Advantages & Challenges

Advantages:
- Higher bioavailability compared to oral arginine
- Longer plasma half-life → sustained NO boost
- Better tolerance at high doses (less gastrointestinal discomfort)
- Can be combined with malate (citrulline malate) for added pH buffering in endurance settings
Challenges:
- Hygroscopic in powder form — needs anti-caking solutions for sachets
- Sour taste in malate form — requires flavor balancing in high-dose blends
- Premium ingredient cost vs arginine

Arginine: Advantages & Challenges

Advantages:
- Direct NO precursor — faster initial effect when absorbed
- Widely recognized and understood by consumers
- Lower cost per active gram
- Can be used in nitrate-bound forms (arginine nitrate) for synergistic NO release
Challenges:
- Low oral bioavailability (40–50%) due to arginase breakdown in the liver
- High doses (>6 g) can cause gastrointestinal upset
- More sensitive to oxidation and hygroscopicity in open powder blends

Which One Should Brands Choose?

Citrulline is the go-to for science-backed performance claims and sustained NO levels — ideal for premium, endurance, and advanced preworkouts.
Arginine still holds a place in budget-friendly formulas, or where rapid onset is desired, especially when paired with other NO boosters like nitrates or beetroot.

Many successful formulas stack citrulline + arginine in a staggered-release blend for both immediate and sustained NO support..