L-Citrulline · L-Citrulline
Arginine precursor that actually works better than arginine. Meta-analyses show small blood-pressure reductions.
Short answer
Solid mechanism, modest but replicated effects. The non-stimulant pump supplement with actual data.
Product and dose overview
L-Citrulline (L-Citrulline) is a cardiovascular / performance with evidence grade C, meaning it is backed by mixed or small human trials. We track 0 products containing L-Citrulline. The top-ranked product scores 0 out of 10 on our composite scale (dose, evidence, price, testing, transparency). Prices range up to $0.00 per month.
What it is
An amino acid from watermelon that your kidneys convert into arginine, which then makes nitric oxide — the molecule that relaxes blood vessels.
Why people take it
Supplementing arginine directly mostly fails because the liver breaks it down. Citrulline sidesteps that. Meta-analyses of trials show it lowers blood pressure by a few points, and athletes use it for modest endurance and soreness benefits.
Our verdict
Solid mechanism, modest but replicated effects. The non-stimulant pump supplement with actual data.
Structure & class
Non-protein amino acid, converted by kidneys to L-arginine, substrate for endothelial nitric oxide synthase (eNOS).
Mechanism & clinical data
Barkhidarian et al. 2019 meta-analysis of 8 RCTs: citrulline (≥3 g/day) significantly reduced systolic and diastolic blood pressure, effects larger in hypertensive participants. Exercise trials show reduced muscle soreness (~40% at 48h in some trials) and small endurance gains at 6-8 g citrulline malate.
Pharmacokinetics
Peak plasma arginine 1-2 hours post-dose; vascular effects last several hours.
Dose & forms
What to watch out for
Citrulline malate 2:1 delivers about two-thirds citrulline by weight — a 6 g dose is really 4 g. Pre-workout products routinely underdose at 1-2 g.
Where this dose comes from
The trial dose above is our editorial pick from the published human trials for this ingredient. We choose the dose that the best-available studies used on the endpoint most relevant to longevity. The range shows the lowest and highest doses tested in published trials. The landmark studies below are the papers we read to set it. You can click through and check our work.
When new trials publish, our automated sweeps flag them. If a new study materially changes the dose, we update it through editorial review and record the old dose, new dose, and the triggering study in every affected product's recommendation history. The dose is never changed automatically.
Regulatory status
Timeline
Regulatory events, evidence grade changes, and key research milestones for L-Citrulline, most recent first. Studies link to the paper; regulatory entries name and link the responsible authority.
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EU Court sharpens the bar for botanical health claimsA Court of Justice of the European Union ruling in April 2025 further tightened the requirements for how botanical ingredients (herbs, plant extracts) can be marketed with health claims in the EU, effectively removing much of the flexibility of the on-hold list.
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EU report identifies 117 supplement substances as potential health risksThe HoA Working Group on Food Supplements (26 European countries) published its first report evaluating 117 substances used in food supplements. Of these, 65 were assessed as likely novel foods, 6 were already regulated, 34 had insufficient data, and 12 were prioritized for Article 8 restriction under Regulation (EC) No 1925/2006. The 12 priority substances include ashwagandha, curcumin, melatonin, piperine, St. John's wort, coumarin, p-synephrine, maca, holy basil, Melaleuca, black cohosh, and L-tryptophan. The report drew on 1,500 RASFF alerts reviewed between 2017 and mid-2022.
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Barkhidarian et al. 2019 (Avicenna J Phytomed)Meta-analysis of 8 RCTs: citrulline supplementation significantly reduced systolic (-4.1 mmHg) and diastolic (-2.1 mmHg) blood pressure, especially at ≥6 g/day.
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EU Health Claims Regulation adoptedRegulation (EC) No 1924/2006 laid down harmonised rules for nutrition and health claims made on foods, including supplements. Only claims listed in the EU Register of authorised claims can be used. Rejected botanical claims are held in a separate on-hold list.
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EU introduces the Novel Food RegulationRegulation (EC) No 258/97 required any food or food ingredient without a history of consumption in the EU before 15 May 1997 to be authorised before being placed on the market. This is the framework that captures NMN, spermidine as a supplement ingredient, urolithin A, and many other longevity actives.
Landmark studies
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Barkhidarian et al. 2019 (Avicenna J Phytomed)
Meta-analysis of 8 RCTs: citrulline supplementation significantly reduced systolic (-4.1 mmHg) and diastolic (-2.1 mmHg) blood pressure, especially at ≥6 g/day.
Read study →
Found in these products
All products in our catalog that contain L-Citrulline, ranked by our overall score. Ranking is editorial, never paid.
No products in our catalog contain this yet.
Buying guides and comparisons
Related ingredients
See all in Cardiovascular / Performance →Molecules in the same class, plus the actives most often formulated alongside L-Citrulline in our catalogue.
See L-Citrulline in context: the mechanism it acts through, the biomarker it moves, the products that dose it, and the trials that tested it.
View L-Citrulline on the Longevity Map →Frequently asked questions
What is L-Citrulline?
An amino acid from watermelon that your kidneys convert into arginine, which then makes nitric oxide — the molecule that relaxes blood vessels.
What dose of L-Citrulline should I take?
The trial dose in published human studies is 3000 mg per day, with a range of 1500 to 8000 mg per day. Always consult a qualified clinician before starting any supplement.
Is L-Citrulline safe?
Citrulline malate 2:1 delivers about two-thirds citrulline by weight — a 6 g dose is really 4 g. Pre-workout products routinely underdose at 1-2 g.
What is the best L-Citrulline supplement?
We track 0 products containing L-Citrulline. The top-ranked product scores 0 out of 10 on our composite scale, which evaluates dose, evidence, price, third-party testing, and transparency. See the comparison table above. Scores are editorial judgments, not a scientific standard.
What is the evidence grade for L-Citrulline?
L-Citrulline has evidence grade C, meaning it is backed by mixed or small human trials. Grade A means replicated human RCTs with hard endpoints. Grade B means human RCTs with biomarker outcomes. Grade C means mixed or small human trials. See our evidence grading methodology.
Data verification
Evidence grades are reviewed when new human RCTs are published. Product counts update automatically as new products are added. Dose ranges reflect published trial data, not brand recommendations. Read how we verify.