The popularity of l-citrulline and l-citrulline malate focus primarily on l-citrulline’s ability to raise nitric oxide levels and relax arterial stiffness (1).
Both forms of l-citrulline do this, but choosing which form to supplement with will come down to the question of why you are taking it.
What is l-citrulline?
L-citrulline is a non-essential amino acid that has 3 major roles in the body (3).
Roles 1 and 2 likely don’t matter very much to you. Instead, we’re all about l-citrulline’s nitric oxide production.
So how does l-citrulline create nitric oxide?
L-citrulline assists in nitric oxide creation as a direct participant in l-arginine synthesis (7). This newly created l-arginine then goes on to interact with oxygen and NOS to create nitric oxide and l-citrulline (as a byproduct) (8).
You can see the whole process below, where l-citrulline becomes l-arginine while neutralizing ammonia, then for that l-arginine to become l-citrulline again while also producing nitric oxide.
This image was modified from examine.com, thank you Kamal!
Why do we take l-citrulline instead of l-arginine?
We choose to supplement with l-citrulline over straight l-arginine because l-citrulline enters the blood stream more effectively (9). Supplemental l-arginine on the other hand is largely destroyed by both the intestines and liver (10).
What l-citrulline malate is:
L-citrulline malate is citrulline + malic acid (11).
You can find it as both l-citrulline malate and l-citrulline dl-malate. The dl-malate refers to 2 l-citrulline’s per 1 malic acid whereas standard is 1:1.
What does l-citrulline malate do?
Like standard l-citrulline, l-citrulline malate raises nitric oxide levels.
However unlike l-citrulline, the malic acid in l-citrulline malate participates in the Krebs cycle (12).
In fact, shortages of malic acid in the body are attributed with chronic fatigue (13)… Something an athlete always wishes to avoid.
So, which do I take? L-citrulline or l-citrulline malate?
It’s all depends on your goals.
If you simply want to increase circulation for male vitality, then standard l-citrulline is fine.
However if you are an athlete, then there is no other option than l-citrulline malate; and here’s why…
The benefits of l-citrulline malate supplementation
Since malic acid participates in the Krebs cycle, supplementing with malic acid via l-citrulline malate increases energy components that often get depleted during prolonged exercise. Pair this with l-citrulline’s circulatory effect, and we have enhanced performance that looks like this…
Perform more reps weight lifting with citrulline malate:
Participants supplementing with citrulline malate before exercise were able to complete significantly more reps in both upper body and lower body weight lifting workouts (14).
The measureable effects of citrulline malate supplementation include increased endurance, more reps, and greater explosive power – all of which are applicable to competitive sports performance (17).
Build more muscle with l-citrulline malate:
L-citrulline has been well noted for its ability it increase the work performed while training. However, a recent study suggests that l-citrulline may also contain anabolic properties, through either promoting nitrogen balance or directly activating protein synthesis (18).
Recover faster with l-citrulline malate:
Several of the above cited studies mention l-citrulline malate’s ability to improve recovery. Though, this effect isn’t as predominant as other sports supplements.
L-citrulline malate dosage: how much l-citrulline malate should I take?
The cool thing about l-citrulline malate, is that its benefits can be realized with acute supplementation.
That means, you don’t need to take it consistently for days or weeks in order for it to work, like say beta-alanine, BCAAs, or creatine.
A review of l-citrulline and l-citrulline malate
Overall, l-citrulline and l-citrulline malate are notable ingredients for performance enhancement. They are uniquely able to increase nitric oxide and performance in a dose-dependent acute manner, and have been deemed quite safe (22).
This has led to many supplement brands including l-citrulline malate in their pre workout supplements, most notably Pre-Jym by Jim Stoppani (23).
Really, the only bad rap on l-citrulline malate originates from this study:
In a double-blind placebo study, participants look either 8 grams of l-citrulline malate or placebo and then performed German volume training (24). The result was that the placebo group actually out-performed the l-citrulline malate group.
However what isn’t discussed, is that the placebo was 6 grams of citric acid, which, isn’t really a placebo as it has been found to increase performance and like citrulline malate, participates in the citric acid cycle (25).
So basically, there wasn’t a zero-supplement group. This was a comparison between citric acid and l-citrulline malate over 2 workouts – that’s it!
Due to this, we don’t feel a burn on the reputation of l-citrulline malate.
Are there any side effects?
Besides getting a great pump, there doesn’t appear to be any. Though, if you take too much, diarrhea may ensue. Try not to take more than 8 grams per day.
Best l-citrulline malate supplements
You can find l-citrulline and l-citrulline malate all across Amazon and Bodybuilding.com, however instead of buying stand-alone l-citrulline malate – we prefer to get it through our pre workout supplement.
How is l-citrulline made? Is it from watermelons?
Many brands advertise l-citrulline as ‘an amino acid prevalent in watermelons’ thus leading you to believe that they are in fact sourcing this ingredient from watermelons.
This isn’t the case.