Citrulline aspartate

Amino-acidCitrulline salt

What is it

Citrulline aspartate is a 1:1 salt of the amino acid L-citrulline and aspartic acid. It is marketed as a sports performance supplement aimed at endurance, recovery, and reduction of exercise fatigue.

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Exercise performance / fatigue

Limited Evidence

Short-term human studies, mostly with citrulline malate, suggest modest improvements in repetition volume and reductions in muscle soreness. Studies specifically of citrulline aspartate are older and fewer in number.

General fatigue (Stimol indication)

Limited Evidence

Citrulline aspartate has historical use in Europe for asthenia/fatigue. Evidence consists mostly of older, smaller European trials.

How it works

After ingestion, citrulline aspartate dissociates into L-citrulline and L-aspartate. L-citrulline is converted in the kidneys to L-arginine, which is the substrate for nitric oxide (NO) production. Increased NO can dilate blood vessels and improve blood flow to working muscles. Aspartate participates in the urea cycle and the malate-aspartate shuttle that supports mitochondrial energy metabolism. The combination has been used since the 1970s in France under the brand name Stimol for fatigue. Modern sports research has typically focused on citrulline malate (a related form) rather than citrulline aspartate.

Dosage

Typical sports doses range from 3-8 grams of citrulline (or citrulline salts) taken 30-60 minutes before exercise. Stimol historically used 1-3 grams of citrulline aspartate daily. DSLD label data did not include a median dose.

When and how to take it

WHEN: 30-60 minutes before training for performance effects; chronic dosing across the day may also be effective for fatigue reduction. HOW: Mixed in water as a powder or in pre-workout formulas. Tolerance varies; start with a moderate dose and increase if comfortable.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Citrulline aspartate (powder/capsule)

Common in European fatigue formulations.

Well absorbed; raises plasma arginine more efficiently than oral arginine.

Citrulline malate (alternative)

More commonly seen in pre-workout supplements.

Similar pharmacokinetics; more sports research.

Safety

Generally well tolerated. Possible gastrointestinal discomfort (gas, mild diarrhea) at high doses. No serious adverse effects reported in short-term sports trials.

Who should be cautious

Avoid combining with vasodilating medications without medical supervision. Use caution in those with low blood pressure or kidney disease. Safety in pregnancy and lactation is not well studied.

Interactions

May potentiate the effects of nitrate-based medications (nitroglycerin) and PDE5 inhibitors (sildenafil, tadalafil) by increasing NO availability. Discuss with a clinician if you use blood pressure or erectile dysfunction medications.

Food sources

Watermelon (rind and flesh)

Amount
Variable; ~250 mg citrulline per cup
%DV
—

Cucumber, pumpkin (small amounts)

Amount
Variable
%DV
—

Frequently asked questions

Is citrulline aspartate the same as citrulline malate?⌄

Both are citrulline salts but the second molecule differs (aspartate vs malate). Effects on plasma citrulline and arginine are similar. Aspartate is more common in European medical use; malate is more common in sports supplements.

Is citrulline better than arginine?⌄

Yes for raising arginine in the blood. Oral arginine is heavily metabolized in the gut, so citrulline (which is converted to arginine by the kidneys) is a more efficient way to boost circulating arginine.

References

Citrulline aspartate on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Citrulline aspartate (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.