Best L-Citrulline Supplement

If you're among the nearly 50% of Americans trying to lose weight and get in shape, you've likely considered pre-workout supplements. Thousands of brands on the market promise everything from bulking you up to burning fat and boosting metabolism. Some of their products work well, while others amount to little more than snake oil.

L-citrulline and citrulline malate supplements have been shown to enhance athletic performance by boosting the body's nitric oxide production, increasing blood flow, and providing endurance and strength for more strenuous workouts.1 Those effects also offer benefits for certain cardiovascular conditions and, in some cases, may even help treat erectile dysfunction (ED).

We tested the top brands of citrulline supplements and determined clear winners for various goals.

If you don't have time to read our complete guide, here’s a rundown of our top picks below.

At Innerbody Research, we extensively test each health service or product we review, including citrulline supplements. On top of our personal interactions with these products, our team devoted more than 500 hours to reviewing hundreds of research papers about physical and cardiovascular fitness, sexual health, and citrulline’s role in either.

Trying these out for ourselves allows us to relay to you critical factors like taste, mixability, and even efficacy, albeit in a small sample size. It also allows us to speak with confidence to each company’s customer service, shipping logistics, and, where necessary, return procedures.

Additionally, like all health-related content on this website, this review was thoroughly vetted by one or more members of our Medical Review Board for accuracy. We’ll keep our eyes on the citrulline landscape in the coming weeks and months to keep our recommendations as current as possible.

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions about staying healthy and living healthier lifestyles.

We considered five primary criteria to evaluate our top citrulline supplements: effectiveness, cost, safety, taste, and customer experience. We typically give the most weight in our considerations to effectiveness, and that was true of our process here. And while supplements containing nothing but L-citrulline should be comparatively safe, we dug a little deeper, scrutinizing various companies' approaches to safety, including things like third-party testing and ingredient sourcing. Cost plays a smaller role here than it does in other guides we’ve produced, mainly because so many L-citrulline supplements fall into similar pricing patterns.

The fact that we tried these supplements for ourselves allows us to speak to taste, which we believe is crucial for a product you’ll likely consume almost daily. And our last point of focus, customer service, has the least power over our ultimate decisions, but we take it into account as a potential tiebreaker for readers who might be having a hard time choosing.

Effectiveness

Winners: PureBulk L-Citrulline DL-Malate and Kaged Pre-Kaged Elite

The appearance of a tie in this category is somewhat deceiving. We gave the award to two products because one falls into a class of L-citrulline supplements designed to provide L-citrulline alone (sometimes along with malic acid), and the other is a complex pre-workout drink that is built around a high L-citrulline dose.

PureBulk’s L-Citrulline DL-Malate is our top choice overall because it provides a high enough recommended dose that you can titrate up or down as you see fit, thanks to its minimal ingredient profile. There is also evidence that the addition of malic acid can improve the action of L-citrulline while offering complementary benefits of its own.2

As far as recommended serving sizes go, the 10g dose of L-citrulline in Kaged Pre-Kaged Elite is one of the largest we’ve seen. And since effective doses in workout-related studies typically start between 6g and 8g, safely ranging into the high teens, that 10g dose is likely to be effective for most users. The litany of other ingredients tuned to enhance exercise performance is equally impressive, both in terms of component choice and dosages.

There isn’t much comparison between the two, and your specific needs will be the thing that sends you in one direction or another.

Cost

Winner: Transparent Labs Fermented L-Citrulline

Cost comparisons among L-citrulline supplements aren’t particularly straightforward. Additional ingredients — whether simply malic acid or a slew of pre-workout aids — will impact price significantly. But if you’re just looking to get the most high-quality L-citrulline you can for your money, we believe Transparent Labs offers the best price you’ll find. 240g of its Fermented L-Citrulline costs $17.99 for a one-time purchase, but that comes down to $16,19 when you subscribe for automatic shipments. Subscribing also unlocks free shipping, keeping costs low.

You can buy larger quantities of L-citrulline from PureBulk and other bulk suppliers, but we consider the high price of those large quantities to be too cost-prohibitive for many people, even if the cost per gram of L-citrulline is superior to Transparent Labs. If you’re looking for a reasonable amount of the substance from a good company, it’s definitely the way to go. That said, PureBulk can still be considered a runner-up here. Its L-Citrulline DL-Malate only loses out to Transparent Labs by about $1. Its 2:1 ratio of L-citrulline to malic acid means you only get 2/3 the amount of L-citrulline you’d get from the same-sized container of Transparent Labs Fermented L-Citrulline, but given the evidence that malic acid can improve L-citrulline absorption, the difference there may be a wash. PureBulk lacks a subscription program for its L-citrulline, and you can’t get free ground shipping unless you spend at least $49.

Safety

Winner: PureBulk L-Citrulline DL-Malate

As far as safety is concerned, L-citrulline on its own doesn’t pose too many risks for healthy individuals. Because it’s a precursor to L-arginine, which causes vasodilation and reduces blood pressure, it can pose certain dangers to consumers with cardiovascular conditions or those who take medications that affect their blood pressure.

But those risks aren’t inherent to one brand over another, even comparing L-citrulline and L-citrulline DL-malate. So, how can we award one company higher marks for safety than another? The answer comes down to manufacturing and transparency.

With a name like Transparent Labs, you might have expected to see that company take this category, and it’s fair to say they’re a close second. Both Transparent Labs and PureBulk produce simple L-citrulline supplements with no added ingredients, and both companies subject their products to third-party testing and make those results available to the public.

However, PureBulk is a little more up-front about the potential allergens you won’t find in its L-Citrulline DL-Malate. It explicitly states that its product is free from the following:

• Sugar
• Soy
• Dairy
• Yeast
• Gluten
• Corn
• Additives

By comparison, Transparent Labs only says that its L-citrulline product is vegan. Neither company offers information about the source ingredients from which they derive their respective L-citrulline. Hopefully, they’ll remedy that in the future.

Taste

Winner: Transparent Labs STIM-FREE

To be fair, plain L-citrulline supplements don’t really taste like anything, so both Transparent Labs Fermented L-Citrulline and PureBulk L-Citrulline DL-Malate are great choices if you want to add them to water or mix them into a smoothie. But in terms of an individual L-citrulline supplement tasting good of its own accord, STIM-FREE is a clear winner.

Transparent Labs offers eight flavors compared to Kaged’s five. That means you’re more likely to find a flavor that suits you from Transparent Labs. But our testers all agreed that Transparent Labs’ use of stevia as a sweetener gave its blends a more natural taste compared to the artificial taste we got from the sucralose in the Kaged formulas.

Both Transparent Labs and Kaged offer pre-workouts that mix into water with about the same quality, though we should note that pure L-citrulline mixes most thoroughly.

Customer experience

Winner: Transparent Labs

We’ve dealt with the companies in this guide and their main competitors on numerous occasions while investigating products and ordering them for ourselves. The overall experience with each is relatively similar, but Transparent Labs has usually caused us the fewest headaches.

For example, we deeply appreciate it when a company subjects its products to third-party testing, but not all companies make the results of that testing available. Transparent Labs and PureBulk both offer those results to the public, but whereas PureBulk asks you to email them for a specific certificate, Transparent Labs maintains a database of them that you can find by searching the lot number on any product you receive in the mail.

That little extra bit of simplicity permeates Transparent Labs’ structure. It isn’t perfect (the hours of attendance for its chat support are quite wonky), but it’s better than most and just superior enough to the two other companies in this guide to warrant a win here.

The chart below shows how our top recommendations compare in terms of cost, ingredients, and more. Your product choice will mostly depend on your lifestyle, budget, and dietary needs.

These price comparisons are based on single purchases of each product and do not account for subscription plans or bulk purchases, which can often earn more savings.

L-citrulline is a nonessential amino acid that’s produced in the body but is also available through diet. When you ingest L-citrulline supplements or foods containing L-citrulline, the kidneys transform it into L-arginine, another nonessential amino acid known for increasing nitric oxide production. These compounds benefit heart and blood vessel health and may boost the immune system.

One of the primary reasons people take citrulline supplements is to increase endurance during intense workouts. Others take them to help lower blood pressure or address symptoms of erectile dysfunction.

Some of the likeliest benefits you'll encounter from taking a citrulline supplement include:

• Reduced hypertension3
• Improved sexual function4
• Greater endurance in the gym5
• Reduced fatigue
• Reduced post-workout soreness6
• Improved immunity7

L-citrulline (CIT) is an organic nonessential amino acid primarily derived from watermelons. It is also naturally produced in the body through endogenous synthesis in the liver and intestines. It is rarely attained from a regular diet (unless you live on a watermelon farm).

Citrulline's primary functions in the body are helping eliminate harmful substances like ammonia through the urine and promoting nitrous oxide production and vasodilation.

Studies examining long-term L-citrulline use have demonstrated that supplementation may reduce systolic blood pressure and can reduce diastolic blood pressure at doses greater than or equal to six grams per day.8 Acute use of similar doses has also resulted in positive effects.9 For those at risk of heart disease and hypertension, supplementing citrulline may help prevent the need for medications down the line, though this is a sensitive enough area of your health that you should definitely speak with your doctor before taking it.

Citrulline supplements aid athletic performance by promoting nitric oxide production in the body, increasing the amount of oxygen in your muscle tissues. Nitric oxide modulates:

• Mitochondrial respiration
• Muscle energy
• Metabolism
• Blood flow

Thus, increasing nitric oxide production can improve endurance and reduce muscle soreness during and after workouts. It can also increase blood flow to the sexual organs, potentially addressing symptoms of erectile dysfunction.

In studies of CIT supplementation in elderly and malnourished rats, researchers showed that those who received supplements gained muscle protein, especially when supplemented with branched-chain amino acids (leucine, valine, and isoleucine) as well.10 More human studies would be useful.

Citrulline malate (CM) combines L-citrulline with DL-malate (essentially malic acid), a compound derived from apples that may assist in converting food to energy. Originally developed for treating asthenia (abnormal physical weakness and lack of energy), citrulline malate supplements have been shown to improve athletic performance in numerous scientific trials.

This 2016 study showed that CM supplementation improved tennis performance in female subjects, specifically improving power and endurance.11 A 2015 study showed that CM supplementation improved muscle performance while having no significant impact on lactic acid levels for advanced weightlifters during repeated bouts of lower-body exercise.12

There is also some evidence that L-citrulline uptake is improved in the presence of malic acid. That means more of the L-citrulline you take will have an opportunity to work in your body. And malic acid offers health benefits of its own, protecting both cardiometabolic health13 and the balance of beneficial microbes in the gut.14

For this reason, we believe that L-citrulline DL-malate supplements offer greater benefits than L-citrulline on its own. That said, L-citrulline supplements are still a viable option, particularly if budget is a primary concern.

L-Citrulline supplements are a great choice for those who are already considered healthy, especially when it comes to cardiovascular health. They’re ideal for those looking to increase exercise performance and decrease recovery time with a single ingredient. They may also provide some relief for men who have sporadic experiences with mild erectile dysfunction.

Serious athletes can also look for pre-workout supplements that contain a significant amount of L-citrulline. These will often also contain caffeine, BCAAs, vitamin complexes, and other components intended to improve exercise performance. Because of this blend of ingredients, many pre-workouts skimp on one or more of each, leading to underdosing and sometimes a lack of efficacy. The pre-workouts we recommend as L-citrulline supplements each contain clinically relevant doses of L-citrulline and other beneficial ingredients.

Who shouldn't use citrulline supplements

If you’re taking vasodilators or other medications for blood pressure, you should not take citrulline supplements without first consulting your doctor. These supplements can lower blood pressure to dangerous levels when combined with certain medications.

Examples of vasodilators include:

• Alprostadil IV
• Corlopam
• Deponit
• Fenoldopam
• Glyceryl trinitrate transdermal
• Hydralazine
• Loniten
• Minitran

Other medications that interact with citrulline supplements include those prescribed for erectile dysfunction, such as:

• Tadalafil (Cialis)
• Sildenafil (Revatio, Viagra)
• Vardenafil (Levitra, Staxyn)
• Stendra

Pregnant or nursing individuals should also avoid citrulline supplements. Anyone with a chronic medical condition or those taking medications should talk to their doctor before beginning any new dietary supplement.

L-citrulline and citrulline malate supplements are generally safe for healthy individuals, and research has used doses of up to 15g/day without serious adverse effects.15 Like any supplement, even the healthiest individuals might experience some nausea, headaches, or gastrointestinal discomfort when beginning a new regimen. These symptoms typically fade, but if they don’t, you should talk to your doctor.

While healthy individuals should be fine taking L-citrulline supplements, the potential for certain contraindications and cardiovascular effects makes L-citrulline supplements a little more dangerous than some others. We’ve just listed a handful of blood pressure and ED medications that can have negative interactions with L-citrulline, but even if you aren’t on any such medication, you may still have a level of cardiovascular fitness that can suffer from L-citrulline supplementation.

It would be wise for even healthy people to get their blood pressure checked before taking L-citrulline and to make an appointment to talk to their doctors about any and all cardiovascular issues they may have experienced, just to rule out any possible underlying risks.

Best overall and best for bulk purchasing

PureBulk is a supplement marketplace that offers large quantities of its supplements to bulk buyers and smaller sizes for regular customers. Its L-Citrulline DL-Malate delivers a plain, well-researched ingredient profile at a very reasonable price. In fact, its price per gram can get lower than Transparent Labs if you’re willing to spend more money up-front. But that investment level might be too high for many customers.

PureBulk is our top recommendation for most people in 2024, however. Its effective form of L-citrulline is free of the following:

• Dairy
• Soy
• Yeast
• Sugar
• Gluten
• Corn
• Additives

Possibly the least convenient thing about it is that it doesn’t come with a scoop, which makes measuring out a dose annoying until you get to the point where you can eyeball it.

Taste and mixability

Any L-citrulline supplement that comes to you unflavored and without many other ingredients is going to mix well with water. After a brief stir, it all but dissolves completely. On the taste side, there is almost nothing to detect. If you don’t like drinking plain water, you won’t like plain water with L-citrulline in it. But because it has next to no flavor, you can add it to just about anything.

Pricing

PureBulk offers its L-Citrulline DL-Malate in five sizes, each of which reduces the cost per gram as you move up the ladder. Here’s how it breaks down:

To be clear: there are significant savings per gram between the 500g and 1kg levels, but we rounded down to $0.06 for the 500g level and up to $0.06 for the 1kg level.

You can get free shipping from PureBulk on orders over $49. For L-citrulline, that will only apply to the 1kg bag and up. But you can shop around on the site and find plenty of well-made supplements that can get you to $49 with relative ease. If you miss the mark, shipping is calculated based on location. For reference, shipments to our offices in the NY metro area cost just over $4.

PureBulk has a strangely limited return policy regarding opened products. It certainly doesn’t amount to a money-back guarantee, but it is something. For an unspecified amount of time, the company will let you return a product. If it’s unopened, and you haven’t waited so long that the product has expired or come close to it, you’ll probably get a full refund minus shipping charges. If it is opened, the company will only refund you the value of that product’s smallest available quantity.

For example, you could order a 1kg bag to save on shipping, and if you tried to return it after using it a few times, you’d only be eligible to receive a refund for the value of a 100g bag, which is the smallest available quantity. That’s a loss of more than $50 before you account for return shipping. We’d like to see a more forgiving policy here, but it isn’t that unusual for suppliers in this space to be strict. No product on this list offers a proper money-back guarantee.

Best budget pick, best pre-workout (stim-free), and best tasting

When shopping for L-citrulline supplements, some people desire simplicity. Transparent Labs’ Transparent Labs L-Citrulline Fermented provides 2,000mg of fermented L-citrulline in every scoop, with no additives, flavorings, colorings, or sweeteners. The jar contains 240g for a total of 120 servings. It’s priced extremely well, but unlike PureBulk’s product, this one doesn’t contain malic acid, so it might not absorb as well as L-citrulline DL-malate would.

Transparent Labs makes two other very appealing supplements containing L-citrulline DL-malate in its BULK and STIM-FREE pre-workouts. Between the two, we prefer STIM-FREE. BULK has a superior ingredient profile overall, but if you want a caffeinated pre-workout, you can get even higher doses of more ingredients from Kaged’s Pre-Kaged Elite. STIM-FREE, despite being generally weaker than BULK, still offers the best combination of ingredients and doses in a caffeine-free pre-workout built around L-citrulline.

Here’s a side-by-side look at some key ingredients in BULK and STIM-FREE from Transparent Labs, with Pre-Kaged Elite thrown in for added context:

While it lacks the caffeine content and is 2g weaker in L-citrulline DL-malate, STIM-FREE is the only one of the three pre-workouts to contain BCAAs or choline, the latter of which can help provide the focus others would rely on caffeine to create.16

Taste and mixability

Transparent Labs sells both an unflavored L-citrulline supplement and two flavored options in its pre-workouts. These flavored drinks mix pretty well into water — not as well as simple L-citrulline, but better than some competitors in the space. Stirring the powder into a glass of water resulted in only a small amount of clumping. Escalating that stir to a mix in a shaker cup took care of those clumps.

Thanks to being sweetened with stevia, Transparent Labs pre-workouts have a mild, fruity taste that doesn’t result in the kind of cringe you’d get with more artificial flavors and sweeteners. Each is available in the following flavors:

Pricing

Transparent Labs offers all three of its L-citrulline-based supplements as one-time purchases or as part of a subscription program. Its pre-workouts are also available within larger stacks built around targeted goals like weight loss or muscle building. For now, let’s look at how the pricing compares for L-citrulline supplements as one-time or subscription purchases.

Shipping from Transparent Labs starts at $7.99, but it’s free on subscription orders and on orders over $149. That’s a pretty high threshold for free shipping compared to the field. PureBulk offers free shipping once you get over $49, and Kaged offers it on orders over $79 (though this policy may be even more generous, as described below).

With that potential for free shipping on a subscription, Transparent Labs Fermented L-Citrulline becomes the best deal of the supplements we considered for this guide.

Best pre-workout (with caffeine)

Like Transparent Labs, Kaged sells plain fermented L-citrulline supplements in addition to more complex pre-workout options. Its Pre-Kaged pre-workouts are available caffeinated or stim-free — again, similar to Transparent Labs. But Kaged also sells what it calls Pre-Kaged Elite, a pre-workout that significantly increases the doses of several key ingredients, including L-citrulline.

Here’s a look at the ingredients in Kaged Pre-Kaged Elite:

With such a high dose of L-citrulline and an impressive amount of both creatine and caffeine, the Pre-Kaged Elite formula has nearly everything you might want in a pre-workout. The standard Pre-Kaged and its stim-free equivalent are also impressive, but not as much.

There are several reasons we consider Transparent Labs’ STIM-FREE superior to Pre-Kaged Stim-Free:

1. Transparent Labs uses L-citrulline DL-malate in its pre-workouts instead of fermented L-citrulline.
2. Kaged employs a branded ingredient that consists of a proprietary blend, which obscures its dose.
3. Transparent Labs STIM-FREE offers a larger dose of BCAAs.
4. Transparent Labs includes choline and elevATP for a stim-free source of energy and focus.
5. Pre-Kaged Stim-free is only available in two flavors, compared to the eight you can choose in Transparent Labs’ equivalent.

Taste and mixability

Another parallel between Kaged and Transparent Labs is that both are the companies on this list that offer flavored drinks containing L-citrulline. The difference is that Kaged uses sucralose as a sweetener. Our testers typically find that sucralose imparts more of an artificial aftertaste in anything it sweetens, and Kaged’s products were no exception. (If you like and use Splenda a lot, you might prefer the flavor of Kaged, though.)

Kaged Pre-Kaged Elite is available in the following flavors:

• Glacier Grape
• Caribbean Sunrise
• Orange Mango
• Strawberry Lemonade
• Fruit Punch

Kaged and Transparent Labs pre-workouts mix with the same relative efficiency, almost dissolving into plain water with a vigorous stir and going the rest of the way in a shaker cup. Neither produced any meaningful clumping or sediment, and both offered a good mouthfeel.

Pricing

Since Kaged has four L-citrulline products and a subscription savings program, we thought a simple chart could clarify what you might spend on any of them if you buy direct, but we left off the simple L-citrulline since we can’t recommend it over the Transparent Labs alternative:

A subscription offers savings on the product but doesn’t technically unlock free shipping. We say technically because, despite the company’s claim of a $79 free shipping threshold, we repeatedly got free shipping on less expensive orders. It’s unclear whether this is a fluke or instead reflects a changing policy that may give any order free shipping.

Nonetheless, you can save significant money by buying Pre-Kaged Elite from Amazon instead. A single bottle of Pre-Kaged Elite from Amazon costs $45, compared to $60 when buying direct from Kaged. And a subscription via Amazon cuts your price down to $40.50.

Kaged gives you 30 days to initiate a return, but it won’t accept returns on products that are more than halfway consumed. How exactly the returns team measures out the product to determine this isn’t obvious, but this shouldn't pose too much of an issue for L-citrulline supplements. L-citrulline consumption should produce palpable results after a short amount of time if it’s going to work for your needs, so you should know whether or not you want to stick with a given product before you get halfway through its contents. With that in mind, this ends up being a superior policy to those from either PureBulk or Transparent Labs.