Citrulline is gaining increasing popularity as a supplement that may increase blood flow, with some studies suggesting that it might help with power output and endurance during workouts. This non-essential amino acid is produced in the body and it’s found in nature in legumes, organ meat, and especially watermelon — the name “citrulline” is actually derived from the Latin word for watermelon — and there are dozens of different supplements on the market including powders, pills, and citrulline malate, a form that might be more useful for improving energy production.
Best Citrulline Supplements
- Best Overall: Transparent Labs RawSeries L-Citrulline Malate 2:1
- Best For Kosher Diets: KAGED MUSCLE Citrulline
- Best For Vegans: Doctor’s Best L-Citrulline
- Best Bulk Buy: BulkSupplements Citrulline
- Best Pills: Nutricost L-Citrulline
- Best Citrulline Malate: Hard Rhino L-Citrulline DL-Malate
Editor’s note: The content on BarBend is meant to be informative in nature, but it should not be taken as medical advice. The opinions and articles on this site are not intended for use as diagnosis, prevention, and/or treatment of health problems. It’s always a good idea to talk to your doctor before beginning a new fitness, nutritional, and/or supplement routine. Individual needs for vitamins and minerals will vary.
Best Overall
Transparent Labs is very consistent across their products sustaining a high purity level and this one is no exception. The price point is a bit high, but not enough to be too much of an obstacle when compared to competitive options and the lack of any unnecessary added ingredients is a nice boon.
This product serves 600 grams of citrulline across 100 servings and contains no artificial sweeteners, preservatives, or colorings. It is unflavored and contains only one other ingredient: calcium silicate.
There is something to be said about being flavorless, as that will often make it a easier to mix into whatever your favorite liquid to mix with supplements is. On the opposite end of that spectrum, being flavorless might not be exciting for those who want to consume their supplements enjoyably instead of for the sake of it.
Who Should Buy Transparent Labs RawSeries L-Citrulline Malate 2:1
- Anyone who appreciates a super simple ingredient list.
- Those who are happy to not have any colorings or flavors added to their supplements.
- Folks who desire a non-GMO product.
Who Shouldn’t Buy Transparent Labs RawSeries L-Citrulline Malate 2:1
- People who have to stay on a tighter budget.
There really wasn’t much to here to dock points for — it’s solid all-around citrulline product with a good serving density and respectable dosage recommendation. The only knock is price, but not enough to deny it our top pick.
Best For Kosher Diets
KAGED MUSCLE is known for using fermented amino acids in their products — most competitors obtain amino acids from animal sources, so KAGED MUSCLE’s citrulline is vegan friendly. In addition, it’s been third party tested by Informed Choice, a well known organization that screens for banned substances and impurities. It’s also gluten free, non-GMO, and certified kosher.
Third party tested, non-GMO, gluten free, and even vegan friendly, this is the crème de la crème of citrulline supplements.
This citrulline is third party tested by the well regarded organization Informed Choice. It is one of the rare citrullines that is vegan friendly as well as gluten free, non-GMO, and kosher.
Who Should Buy KAGED MUSCLE Citrulline
- Those who follow kosher diets.
- Anyone who requires their supplements be third party tested for impurities.
- People who prefer their amino acids come from fermented sources.
Who Shouldn’t Buy KAGED MUSCLE Citrulline
- Anyone who dislikes supplements with a pungent smell.
Many consumers report that while it’s tasteless, this citrulline has an unpleasant smell which could be a turn off. That is really the only knock that kept this product from claiming our best overall pick, though. So if you were not impressed or took some issue with our best overall pick, this is probably where you should lean.
Best For Vegans
Inexpensive and one of the few vegan-friendly citrulline supplements, Doctor’s Best has put together a solid product that ticks a lot of boxes: it’s non-GMO, soy-free, gluten-free, made in a cGMP facility, and perhaps most importantly it’s third party tested.
A well priced citrulline that's vegan friendly and has been third party tested for purity.
This citrulline is vegan friendly, obviously, and it is also third party tested to ensure label accuracy and purity. There are enough options on the market that get third party tested, so if you shouldn’t really consider any that aren’t.
Who Should Buy Doctor’s Best L-Citrulline
- Folks who value products made in a current good manufacturing practices facility.
- Anyone who follows a vegan diet.
Who Shouldn’t Buy Doctor’s Best L-Citrulline
- Anyone anxious about secure packaging during delivery.
There are some reports that the bottle can come unsealed during shipping, which is unfortunate. It’s small things like that that can play a huge role in our scoring because even if a product is excellent, if it is not delivered in sound condition, then it won’t have much value regardless of its quality. Hopefully, it is a non-issue for future orders and it is still worth the risk still so it retains a high rank on our list.
Best Bulk Buy
As the name suggests, one can buy BulkSupplements in bags as large as 25 kilograms, but whatever the size of the package (they come as low as 100 grams), it’s always terrific value. The no frills citrulline has no added ingredients and the final product is tested in house for purity.
Far and away the most inexpensive citrulline supplement on the market, plus it's tested for purity and free from major allergens.
BulkSupplements is extraordinarily inexpensive, allergen free, and produced in a Good Manufacturing Practices-certified facility. It’s written that the citrulline is “lab tested for verification and guaranteed purity,” though it’s unclear if this means third party tested.
Who Should Buy BulkSupplements Citrulline
- Anyone on a budget.
- Those who need higher variety of serving size options.
Who Shouldn’t Buy BulkSupplements Citrulline
- Anyone who doesn’t have a way to measure servings.
- Folks who get annoyed when bags don’t reseal smoothly.
BulkSupplements hits a lot of aspects out of the park: low price, clean ingredients, there’s just a lot to like. The areas where they fall short are things that don’t really have to do with the product they are manufacturing but the things that come with it. The product doesn’t come with a serving scoop, so you’ll need measuring spoons or something similar to ensure proper servings sizes. Additionally, the bag it comes in doesn’t offer the easiest time when it comes to trying to reseal it, so it might be best to have a bag clip or separate container. These aren’t huge deals as they are easily solved, but we still have to take it into account in our rankings.
If you are trying to keep supplement spending down and want a really solid product with a simple ingredient list, then look no further.
Best Pills
Nutricost produces a lot of inexpensive supplements and their citrulline pills hit a nice sweet spot between quality and value. The citrulline is non-GMO, it’s gluten free, it’s made in an FDA-registered facility, and it’s third party tested to ensure purity and label accuracy.
Non-GMO, gluten free, made in an FDA-registered facility, and third party tested, these are the best citrulline pills on the market.
On a per gram basis, this is a pretty inexpensive citrulline product, particularly given the fact that it comes in capsules. This form of citrulline is easy to consume on the go, which is a nice boon for avid travelers. It is even third party tested for purity and label accuracy.
Who Should Buy Nutricost L-Citrulline
- Anyone who prefers easy-to-consume supplements.
- Those who need to travel often with supplements.
- People on a tighter budget.
Who Shouldn’t Buy Nutricost L-Citrulline
- The capsules are made from gelatin, so they’re not vegetarian friendly.
- The capsules also contain magnesium stearate and stearic acid, which help keep the powder from sticking to the machinery in the facility in which it’s made — some consider these “fillers” undesirable.
If you’re a vegetarian, you’ll have to look elsewhere as there is gelatin in these capsules. Additionally, the added fillers to streamline production may be a turn off. If you are in the market for a capsule supplement, then these are certainly a top tier consideration as long as those cons don’t put you off too much.
Best Citrulline Malate
Citrulline malate has citrulline combined with malic acid, which is often included in supplements as a preservative but it may also help with stamina. Hard Rhino’s offering is great value, free from major allergens, and tested with Thermo Spectrum analysis to ensure purity and label accuracy.
Lab tested for purity and label accuracy, Hard Rhino's citrulline malate is terrific value and free from major allergens.
This citrulline malate is reasonably priced and made in the United States at an FDA registered facility. It’s guaranteed to be free from major allergens, so it will likely be compatible with most consumers dietary needs.
Who Should Buy Hard Rhino L-Citrulline DL-Malate
- Anyone who wants supplements made in an FDA registered facility.
- Folks looking for a stamina boost.
Who Shouldn’t Buy Hard Rhino L-Citrulline DL-Malate
- People who want their products tested for purity by a third party.
There is really only one major hit against this product and that is that it’s tested for purity and banned substances in-house, not by a third party. That can suffice, but it doesn’t really offer the same credibility. We weight third party testing pretty heavily, but there were enough plusses for this product that it still landed in our top picks.
How We Decided Our Picks
There are a handful of categories that we stuck to weed out the best of the best. Here is how we broke it down:
Dosage vs. Cost
Pretty straightforward ranking system here. If all products are created equal, we rank the less expensive options as better picks. That is, of course, an oversimplification of how we sifted through each pick, but it’s the general idea.
Some products lean into low cost being a huge incentive to pick them — see our best bulk buy option — but price only goes so far. There is also the matter of dosage. Dosage will vary from product to product and the ideal dosage is going to depend pretty much entirely on the consumers needs, so it can be tough to compare. However, if two products have similar per serving doses at a similar price, but one has more servings, then that one will obviously score higher.
Third Party Testing
This is really just a matter of wanting clean quality supplements. Once one competitive option gets third party tested and can verify the purity of their product, it puts the onus pretty heavily on that product’s competitors to do the same. If one product is third party tested and another is not, there is a significant boost in confidence that the product you think you’re buying is the product you’re getting.
Some products test for purity, but do so in house. That is a reasonable way to test, it is unlikely you’ll sell much product if your testing is flawed, but it doesn’t score as well as if a third party tested the product. There is just the inherent bias to test your own product favorably that we have to weight third party testing much more highly.
Form and Ingredients
This is subjective to the consumer, but the variances that come along with a powder versus a capsule are going to be obviously notable. A primary example of this is if a product is a capsule, is it made with something that will exclude vegetarians? On the flip side, if the product is a powder, how well does it mix? Is it flavored? Does it have any particular odor?
There are a lot of minute intricacies to sift through here and a big one is any added ingredients for the sake of easier manufacturing or to maintain form. An example is any additional preservatives or any added ingredients to create a capsule.
What Are the Benefits of Citrulline?
Citrulline is an amino acid that appears to increase plasma levels of arginine and ornithine, improving nitric oxide metabolism.(1)(2)(3) Nitric oxide seems to play a big role in relaxing blood vessels, which has implications for circulatory health and blood flow, and some studies have even linked it to improved erection hardness, making citrulline a somewhat popular supplement for erectile dysfunction.(4)(5)
For athletes, an increase in nitric oxide production might improve both anaerobic training (like sprinting) and aerobic (endurance-based) workouts, in addition to potentially reducing the amount of oxygen needed for exertion.(6)(7)(8)(9)(10) Citrulline itself has been seen in a few studies to improve power output and time to fatigue in cyclists and tennis players.(11)(12)
As for dosing, research in the International Journal of Cardiology and the European Journal of Applied Physiology found that a dose of 5 or so grams of citrulline may increase nitric oxide production and blood flow. (13)(14)
Citrulline vs Citrulline Malate
Citrulline is the pure amino acid, while citrulline malate is an organic compound that occurs naturally in many fruits. It’s citrulline combined with malic acid, which contributes to the sour taste of fruits — it’s abundant in apples and is often used as a flavoring in supplements. While citrulline does have links with improved performance, citrulline malate may also help to provide more energy for high intensity exercise because of its potential role in converting food into usable energy because of its role in in the Krebs cycle.
That’s the theory, anyway. Evidence is a little mixed; there is evidence, like a study published in 2010, that found citrulline malate to be useful at improving the number of repetitions in a training session and improve recovery, and another found it to postpone exercise fatigue in handball players.(15)(16) Other studies have found no effect on performance or muscle soreness.(17)(18)
At this time, we don’t have good research comparing the two supplements against one another and the additional benefits of adding malate aren’t concrete, but it’s a promising supplement nonetheless.
BarBend Tips
Be mindful of the dosage of citrulline. Many supplements will include one or two grams, but research suggests five to eight grams is ideal for the benefits.
It’s possible that loading citrulline over time may be an ideal way to accrue the potential benefits. Some users take a few grams every day for a week before expecting results. At the moment, there’s not quite enough evidence to suggest either acute or chronic dosing is superior.
If natural sources of citrulline are preferred, watermelon is widely considered the best source, though the exact amount present in a serving is unclear. Some estimate that there is about a quarter to half gram of citrulline per cup of watermelon flesh; it’s most concentrated in the white rind surrounding the flesh.
Side effects aren’t widely reported from citrulline supplementation. A very small minority experience upset stomachs or heartburn, so it may be prudent to start with a small dosage and gradually increase.
Wrapping Up
Citrulline is generally considered safe and today it’s one of the most popular ingredients in pre workouts. But always remember, especially if the intention is to take citrulline to improve circulatory health or erectile dysfunction, that it’s important to speak with a physician before starting a new supplement regimen.
References
1. Flam BR, et al. Endothelial nitric oxide production is tightly coupled to the citrulline-NO cycle. Nitric Oxide. 2007 Nov-Dec;17(3-4):115-21.
2. Sureda A, et al. Effects of L-citrulline oral supplementation on polymorphonuclear neutrophils oxidative burst and nitric oxide production after exercise. Free Radic Res. 2009 Sep;43(9):828-35.
3. Nakata M, et al. Endocrinology: nitric oxide-mediated insulin secretion in response to citrulline in islet beta-cells. Pancreas. 2003 Oct;27(3):209-13.
4. Moncada S, et al. The discovery of nitric oxide as the endogenous nitrovasodilator. Hypertension. 1988 Oct;12(4):365-72.
5. Cormio L, et al. Oral L-citrulline supplementation improves erection hardness in men with mild erectile dysfunction. Urology. 2011 Jan;77(1):119-22.
6. Wylie LJ, et al. Dietary nitrate supplementation improves team sport-specific intense intermittent exercise performance. Eur J Appl Physiol. 2013 Jul;113(7):1673-84.
7. Lansley KE, et al. Dietary nitrate supplementation reduces the O2 cost of walking and running: a placebo-controlled study. J Appl Physiol (1985). 2011 Mar;110(3):591-600.
8. Kelly J, et al. Effects of short-term dietary nitrate supplementation on blood pressure, O2 uptake kinetics, and muscle and cognitive function in older adults. Am J Physiol Regul Integr Comp Physiol. 2013 Jan 15;304(2):R73-83.
9. Murphy M, et al. Whole beetroot consumption acutely improves running performance. J Acad Nutr Diet. 2012 Apr;112(4):548-52.
10. Lansley KE, et al. Dietary nitrate supplementation reduces the O2 cost of walking and running: a placebo-controlled study. J Appl Physiol (1985). 2011 Mar;110(3):591-600.
11. Suzuki, T. et al. (2016) Oral L-citrulline supplementation enhances cycling time trial performance in healthy trained men: Double-blind randomized placebo-controlled 2-way crossover study. J Int Soc Sports Nutr. 2016 Feb 19;13:6.
12. Glenn, JM. et al. (2016) Acute citrulline-malate supplementation improves maximal strength and anaerobic power in female, masters athletes tennis players. Eur J Sport Sci. 2016 Nov;16(8):1095-103.
13. Sureda A, et al. L-citrulline-malate influence over branched chain amino acid utilization during exercise. Eur J Appl Physiol. 2010 Sep;110(2):341-51.
14. Ochiai M, et al. Short-term effects of L-citrulline supplementation on arterial stiffness in middle-aged men. Int J Cardiol. 2012 Mar 8;155(2):257-61.
15. Pérez-Guisado J, et al. Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. J Strength Cond Res. 2010 May;24(5):1215-22.
16. Kiyici F, et al. The Effect of Citrulline/Malate on Blood Lactate Levels in Intensive Exercise. Biochem Genet. 2017 Dec;55(5-6):387-394.
17. Chappell AJ, et al. Citrulline malate supplementation does not improve German Volume Training performance or reduce muscle soreness in moderately trained males and females. J Int Soc Sports Nutr. 2018 Aug 10;15(1):42.
18. da Silva DK, et al. Citrulline Malate Does Not Improve Muscle Recovery after Resistance Exercise in Untrained Young Adult Men. Nutrients. 2017 Oct 18;9(10).