L-citrulline is an amino acid named after watermelon, where it was first found. Your body turns it into arginine, which cells use to make nitric oxide, and because it survives digestion better than arginine in some studies, it became a staple of pre-workout formulas. Supplements come in two forms: plain L-citrulline and citrulline malate, which pairs citrulline with malic acid. That second form is where shoppers get confused, because a scoop of malate is only about two-thirds citrulline, and an independent lab test found products labeled 2:1 that held less.
So this ranking rewards what you can check: grams of actual citrulline per serving, the cost of 6 g of citrulline, what testing you can verify, whether the form adds anything, and how far the marketing outruns the research. We read the Supplement Facts panel on every product's current Amazon listing and scored all ten on the same five criteria. For full pre-workout formulas, see our pre-workout ranking.
The short version
- Best overall: BulkSupplements L-Citrulline, plain citrulline at about $0.21 per 6 g.
- Best plain-label powder: Nutricost Pure L-Citrulline, a 3 g scoop with no benefit claims.
- For tested athletes: Kaged Citrulline is on Informed Sport's certified list, which screens batches for banned substances.
- Malate adds nothing measurable. The two trials that compared plain citrulline with citrulline malate found no significant difference.
- Check grams of citrulline. 8 g of a 2:1 malate is about 5.3 g of citrulline, and one lab test found a product labeled 2:1 with only 4.2 g per 8 g.
- The effect is small. The newest meta-analysis, of 30 citrulline malate trials, found a small benefit rated low to very low certainty; separate analyses found no significant difference in maximal strength or endurance.
- No contents certification found. We found no single-ingredient citrulline on NSF's supplement or Certified for Sport listings.
How we ranked them
Citrulline is simple and cheap, so we scored what actually separates products:
- Citrulline per serving and form (25%). Powder giving at least 3 g of citrulline per label serving scores highest, then powder giving 2 to 3 g, then under 2 g, then 1,000 mg pills, then 750 mg capsules, which take 8 for 6 g.
- Cost per 6 g of citrulline (25%), from Amazon prices on October 20 to 21, 2026, counting two-thirds of a 2:1 malate as citrulline. Several trials used 6 g a day of plain citrulline, and 8 g of malate, the most common performance dose, supplies about 5.3 g.
- Verification (20%). We found no single-ingredient citrulline with an NSF contents certification. An Informed Sport listing on the certifier's current list scores next; it screens for banned substances, not label amounts. Then an unnamed or in-house testing claim, then nothing.
- Ingredient form (10%). Plain powder scores highest, then capsules or tablets with excipients, then gelatin capsules, then citrulline malate, because malate showed no added benefit in head-to-head trials and label ratios have measured low.
- Marketing restraint (20%). Products start at 4 of 5, and half a point comes off for each category present: unverifiable superiority or comparison claims, and benefits beyond the human evidence, such as massive pumps, workout results or immune support.
Scores are rounded to one decimal, and ties are ordered by the unrounded score. We also looked at smaller sizes of the same powders, a 1:1 malate (half citrulline), Doctor's Best L-Citrulline and arginine-citrulline blends. No brand paid to be included, and none sent product.
What citrulline research actually shows
Performance: small and uncertain. A 2019 meta-analysis of 12 studies found a small benefit for strength and power (effect size 0.20), but every individual study's confidence interval crossed zero. A 2021 meta-analysis found 6 to 8 g of citrulline malate added about 3 repetitions (6.4 percent) in sets to failure. The newest and largest, a 2026 analysis of 30 trials and 644 people, found a small overall benefit (effect size 0.16), rated low to very low certainty, with no significant difference between dose or timing subgroups. Separate analyses found no significant difference in maximal strength or in endurance and time-to-exhaustion tests.
The famous study is the outlier. A widely quoted 2010 trial reported 52.92 percent more bench press repetitions on 8 g of citrulline malate, but only in the last set, and later trials using the same dose often found no significant difference.
Citrulline versus citrulline malate. Two trials compared the forms directly. In 43 adults, neither 5.3 g of citrulline nor the same citrulline plus 2.7 g of malate beat placebo for strength or repetitions. In 33 trained men over 6 weeks, both improved upper-body repetitions with no apparent difference between them. Malate's proposed energy role comes from an uncontrolled study, and European regulators rejected a citrulline malate claim for faster recovery from fatigue.
Label ratios. A lab analysis of five UK products labeled 2:1 measured ratios from 1.11:1 to 1.92:1; only one was close to its claim, and the product used in that trial held 4.21 g of citrulline per 8 g instead of about 5.3 g. These were UK products tested about 2017 to 2018, but the lesson stands: with malate, you are trusting the stated ratio.
Blood flow and blood pressure. Citrulline raised blood arginine more than arginine itself in one study, though another found similar rises. Single doses of 6 to 12 g of malate did not change artery widening in one trial, while 8 g improved it in another. Over weeks, pooled trials found a small improvement in artery widening. For resting blood pressure, pooled analyses disagree: one pooling five trials found no significant change, while another pooling eight trials found systolic pressure about 4 mmHg lower, with no significant change in diastolic pressure. One positive plain-citrulline trial, a 1.5 percent faster cycling time trial, was funded by Kyowa Hakko Bio, a citrulline maker, and three of its four authors worked there; other positive vascular trials had Kyowa or Kirin (its parent company) ties. More in our nitric oxide supplements ranking.
Erections. One small single-blind study in 24 men with mild erection problems reported improvement on 1.5 g a day, in a fixed order rather than randomized. Erection problems can signal heart disease, so see a doctor rather than self-treat.
The 10 best L-citrulline supplements
Tap any product to jump straight to its full review.
BulkSupplements L-Citrulline Powder (1 kg)
Best for: The most citrulline for the money
The top pick because it delivers the most citrulline for the money: plain L-citrulline, 3 g per teaspoon, nothing added, at about $0.21 for 6 g. Its testing badge names no lab, and a gallery panel promises workout results, while pooled trials show only small, low-certainty effects.
- Plain L-citrulline, so every gram is citrulline
- About $0.21 for 6 g, the lowest cost here
- 3 g per teaspoon, nothing added
- More than 4,600 Amazon ratings averaging 4.7 stars
- Its "third party tested" badge names no lab
- A gallery panel pitches workout results, where pooled trials show small, low-certainty effects
- A 1 kg bag is a lot of powder for occasional use
Nutricost Pure L-Citrulline Powder (600 g)
Best for: Plain citrulline with a claim-free listing
A near tie with BulkSupplements: a 3 g scoop of plain L-citrulline with no malate and nothing added, and a listing with no benefit claims at all, at about $0.30 for 6 g. Its "third party tested" line names no lab, and its NSF mention refers to the factory, not the product.
- Plain L-citrulline with no malate and nothing added
- A 3 g scoop and a listing with no benefit claims
- About $0.30 for 6 g
- More than 3,600 Amazon ratings averaging 4.7 stars
- "Third party tested" names no lab and shows no results
- Its NSF mention refers to the factory, not this product
Bucked Up Essentials L-Citrulline Powder
Best for: Trying citrulline in a small tub
The same 3 g scoop of plain citrulline in a smaller, cheaper tub than the top two, with a listing free of benefit claims, at about $0.36 for 6 g. Its testing claim names no lab, and its warning tells anyone being treated for, or at risk of, any medical condition not to use it.
- 3 g of plain L-citrulline per scoop, nothing added
- A smaller 300 g tub at $17.95 if you want to try it
- A listing with no benefit claims
- "Third party tested" names no lab
- About $0.36 for 6 g, more than the larger bags
- Its warning says not to use it if you are being treated for, or are at risk of, any medical condition, which rules out many buyers
Kaged Citrulline (Unflavored)
Best for: Athletes who need banned-substance testing
The pick for drug-tested athletes: plain fermented L-citrulline on Informed Sport's certified list, which screens batches for banned substances. Informed Sport does not check label amounts, and the listing overstates its case: it says malate has half the citrulline (a 2:1 malate is about two-thirds) and promises massive pumps. A 2 g scoop means three scoops for 6 g, about $0.48.
- Listed by Informed Sport, which tests batches for banned substances; it is on the certifier's October 2026 list, so check your batch number on Informed Sport's site
- Plain fermented L-citrulline with nothing added
- 4.7 stars across nearly 500 Amazon ratings
- Informed Sport screens for banned substances; it does not check the label amount
- Says citrulline malate has "half the citrulline content"; a 2:1 malate is about two-thirds citrulline
- Promises "massive, sleeve-splitting muscle pumps", which trials have not shown
- A 2 g scoop, so 6 g takes three scoops, about $0.48
BulkSupplements L-Citrulline DL-Malate 2:1 (1 kg)
Best for: Buyers who prefer citrulline malate
The best value if you prefer citrulline malate: the label spells out 2 g of citrulline and 1 g of malate per teaspoon, about $0.28 per 6 g of citrulline. Malate added no measurable benefit in head-to-head trials, the usual 8 g dose is nearly three teaspoons, and the testing claim names no lab.
- The cheapest citrulline malate here per gram of citrulline, about $0.28 for 6 g
- The label lists the split: 2 g citrulline and 1 g malate per teaspoon
- More than 9,000 Amazon ratings averaging 4.6 stars
- The usual 8 g trial dose of malate means nearly three teaspoons
- Malate added no measurable benefit in the two trials that compared it with plain citrulline
- Its "third party tested" badge names no lab, and the same workout-results panel appears
Nutricost L-Citrulline Malate 2:1 (600 g)
Best for: A plain-label 2:1 malate
A 3 g scoop of 2:1 citrulline malate with a plain listing, about 2 g of citrulline per scoop at the stated ratio. The panel lists only the total citrulline malate, the Amazon ingredient field lists flow agents the label panel does not, and it costs about $0.45 per 6 g of citrulline.
- A 3 g scoop of 2:1 citrulline malate with a plain listing
- Lots of ratings: more than 4,200, averaging 4.6 stars
- The panel lists 3 g of citrulline malate, not the citrulline amount; at 2:1 that is about 2 g
- The Amazon ingredient field lists calcium silicate and silica, while the label panel lists none
- About $0.45 for 6 g of citrulline, more than Nutricost's own plain L-citrulline at $0.30
- "Third party tested" names no lab
PrimaForce L-Citrulline Malate 2:1 (500 g)
Best for: Small doses of malate
Plain citrulline malate with nothing added, but its 2 g scoop holds only about 1.3 g of citrulline, so the usual 8 g dose is four scoops. About $0.49 per 6 g of citrulline, with an unnamed testing claim.
- Citrulline malate with nothing added
- Nearly 1,900 Amazon ratings averaging 4.6 stars
- A 2 g scoop gives only about 1.3 g of citrulline; the usual 8 g dose is four scoops
- "Always third party tested" names no lab
- About $0.49 for 6 g of citrulline
- Says it uses "only the highest quality ingredients", which cannot be checked
NOW Sports L-Citrulline 1,200 mg (120 tablets)
Best for: People who want a pill
The largest pill here, 1,200 mg per tablet, with a label that warns people on blood pressure medicine or nitrates to check with a doctor. Pills are expensive for citrulline: 6 g would take five tablets, more than the label's two, at about $0.91. It also claims healing and immune benefits trials have not shown.
- 1,200 mg tablets, the largest pill dose here
- The label warns people on blood pressure medicine or nitrates to check with a doctor first
- More than 3,500 Amazon ratings averaging 4.5 stars
- About $0.91 for 6 g, and 6 g would take five tablets, more than the label's two
- "Steroid tested" names no program or lab
- Claims citrulline supports healing and a healthy immune system, which trials have not shown
Nutricost L-Citrulline 750 mg (180 capsules)
Best for: The cheapest capsule
The cheapest capsule per gram, about $0.80 for 6 g, with a plain listing. The 750 mg gelatin capsules mean 8 a day for 6 g, four times the label serving, and the testing claim names no lab.
- The cheapest capsule per gram here, about $0.80 for 6 g
- A plain listing with no benefit claims
- More than 9,000 Amazon ratings averaging 4.6 stars
- 750 mg capsules, so 6 g would take 8 a day; the label directs 2
- Gelatin capsules, so not for vegetarians
- "Third party tested" names no lab
NOW L-Citrulline 750 mg (180 capsules)
Best for: A vegan capsule
Vegan 750 mg capsules from a long-established brand, with a blood pressure and nitrate warning on the label. It is the most expensive way to get citrulline here, about $1.11 for 6 g, and it claims healing and immune benefits trials have not shown.
- Vegan capsules; directions allow up to 4 a day, 3 g
- The label warns people on blood pressure medicine or nitrates to check with a doctor first
- About $1.11 for 6 g, the most expensive here
- 750 mg capsules, so 6 g would take 8
- Claims citrulline supports healing and a healthy immune system, which trials have not shown
- NOW says testing is done in its own labs, not by an independent program
The full lineup, side by side
Amounts come from each product's Supplement Facts panel on its Amazon listing. Citrulline malate is part malic acid, so we compare grams of actual citrulline: a 2:1 malate is about two-thirds citrulline by weight, if the label ratio is accurate.
| Product | Form | Citrulline per serving | Other ingredients | Testing claim or certification | Cost per 6 g citrulline | Score |
|---|---|---|---|---|---|---|
| #1 BulkSupplements L-Citrulline | Powder | 3,000 mg (1 tsp) | None | Unnamed third party | $0.21 | 4.2 |
| #2 Nutricost L-Citrulline | Powder | 3,000 mg (1 scoop) | None | Unnamed third party | $0.30 | 4.2 |
| #3 Bucked Up | Powder | 3,000 mg (1 scoop) | None | Unnamed third party | $0.36 | 4.1 |
| #4 Kaged | Powder | 2,000 mg (1 scoop) | None | Informed Sport (banned substances) | $0.48 | 3.9 |
| #5 BulkSupplements Citrulline Malate | Powder (malate 2:1) | 2,000 mg citrulline (1 tsp) | None | Unnamed third party | $0.28 | 3.8 |
| #6 Nutricost Citrulline Malate | Powder (malate 2:1) | About 2,000 mg citrulline (1 scoop) | None on label | Unnamed third party | $0.45 | 3.7 |
| #7 PrimaForce | Powder (malate 2:1) | About 1,330 mg citrulline (1 scoop) | None | Unnamed third party | $0.49 | 3.4 |
| #8 NOW Sports Tablets | Tablets | 1,200 mg (1 tab) | MCC, stearic acid, coating, more | Unnamed ("steroid tested") | $0.91 | 3.2 |
| #9 Nutricost Capsules | Capsules (gelatin) | 1,500 mg (2 caps) | Gelatin, Mg stearate, silica | Unnamed third party | $0.80 | 3.2 |
| #10 NOW Capsules | Capsules | 1,500 mg (2 caps) | HPMC capsule, stearic acid, silica | In-house lab | $1.11 | 3.0 |
Prices are Amazon prices on October 20 to 21, 2026 and change often. Cost per 6 g is the container price divided by the grams of citrulline it holds (two-thirds of a 2:1 malate), times 6. We checked NSF's listings on October 21, 2026; testing claims are as the brands state them. If you take blood pressure medicine, nitrates or erection medicine, ask your doctor before using citrulline.
How to choose, and what to check first
Count grams of citrulline. Plain L-citrulline is all citrulline. A 2:1 malate is about two-thirds citrulline and a 1:1 malate about half, if the label is accurate, so 8 g of 2:1 malate equals about 5.3 g of plain citrulline. Trials of plain citrulline mostly used about 3 to 8 g.
Pick powder. Effective amounts are several grams, which means one or two scoops of powder versus five to eight pills. Citrulline powder is nearly tasteless and mixes into water or a pre-workout.
Know what a seal means. We found no NSF contents certification for plain citrulline. Informed Sport screens batches for banned substances, which matters for tested athletes but does not confirm the dose.
- Blood pressure, nitrate and erection medicines. Citrulline raises arginine and nitric oxide markers, so its effect could add to these drugs; ask your doctor first.
- Pregnancy. In a trial of 115 pregnant women with preeclampsia, a pregnancy blood pressure disorder, citrulline did not prolong pregnancy, and systolic pressure and liver enzymes were higher at delivery. Avoid it in pregnancy and breastfeeding unless your clinician directs it.
- Kidney disease. The kidneys convert citrulline to arginine; ask your doctor first.
- Stomach upset. About 15 percent of people reported stomach discomfort on 8 g of citrulline malate in one trial; single doses up to 15 g caused no side effects in a small study of 8 men.
- Expectations. The measured benefit is a few extra repetitions at best, with low-certainty evidence; it is not a substitute for training, sleep or food.
Frequently asked questions
Is L-citrulline or citrulline malate better?
Plain L-citrulline gives you more citrulline per gram and usually costs less per gram of citrulline. The two trials that compared the forms directly found no significant difference in performance, so malate's extra cost and weight buy nothing measurable.
How much citrulline should you take?
Performance trials most often used 8 g of citrulline malate, about 5.3 g of citrulline at a 2:1 ratio, taken about an hour before training. Trials of plain citrulline mostly used about 3 to 8 g. A 2026 meta-analysis of citrulline malate trials found no significant difference between dose or timing subgroups.
Does citrulline give you a pump?
It raises blood arginine and nitric oxide markers, but trials disagree on whether a single dose widens blood vessels, and one trial of 8 g of malate found no significant change in muscle swelling. Some people notice a fuller pump; trials have not shown it consistently.
Does citrulline improve workouts?
Slightly at best. Pooled trials found a few extra repetitions in sets to failure, rated low to very low certainty, and no significant difference in maximal strength or endurance.
Does citrulline lower blood pressure?
Pooled trials disagree: one found no significant change in resting blood pressure, another found systolic pressure about 4 mmHg lower, with no significant change in diastolic pressure. If you take blood pressure medicine, ask your doctor before using it.
Is citrulline safe?
Single doses up to 15 g caused no side effects in a small study, and about 15 percent of people reported stomach discomfort on 8 g of citrulline malate in one trial. People on blood pressure, nitrate or erection medicine, people with kidney disease and pregnant women should check with a doctor first.
Is citrulline better than arginine?
In one study, citrulline raised blood arginine more than arginine itself did, partly because arginine is broken down in the gut; another found similar rises at 6 g a day. Neither has strong evidence for exercise performance.
The bottom line
The best citrulline supplement is plain L-citrulline powder at a price that makes several grams cheap. BulkSupplements and Nutricost do that best, Bucked Up is the small-tub option, and Kaged is the pick for drug-tested athletes. If you buy citrulline malate, count grams of citrulline, not powder. Keep expectations modest: the newest analysis found a small benefit with low-certainty evidence, and blood flow and blood pressure results are mixed.