This is one of the favourite fatigue-busting supplement of increasing numbers of athletes, but what is citrulline malate?
If your routine includes resistance training then you could certainly benefit from it.
Do bigger muscle pumps, more muscle pumps, and reduced soreness afterwards sound good?
Let’s explore this supplement in more detail:
What is Citrulline Malate?
Citrulline is a non-essential alpha amino acid that was first isolated from watermelon in 1914.
The word ‘citrulline’ is the latin name for watermelon, and you’ll sometimes hear this supplement referred to as watermelon extract.
‘Malate’ comes from the latin word ‘mālum’ which means apple.
Malate is a salt compound which is often added to foods to preserve them.
It is bound to citrulline in this supplement to help stabilise the substance in the body.
Malate (or malic acid) is what gives unripened apples and some other fruits a sour flavour.
Citrulline malate is rapidly becoming a favourite in preworkout supplements.
It has been used by endurance athletes for many years, but a growing number of encouraging studies are showing that there are benefits to be had by athletes from many disciplines.
Citrulline malate was used as a treatment for fatigue and weakness in Spain, before becoming the supplement of choice for a large number of athletes.
Citrulline is built in the body from two ingredients – ornithine and carbamoyl phosphate, as part of the ‘urea cycle’.
This cycle is how the body processes and removes waste nitrogen.
When the body has extra citrulline as a result of supplementing, the urea cycle is believed to get a massive boost.
This is useful to athletes because muscles produce ammonia as they work, and ammonia is made up of nitrogen.
This nitrogen is grabbed and processed by the turbo-driven urea cycle before it has a chance to cause muscle fatigue.
Citrulline can also contribute to muscle gain.
The kidneys turn excess citrulline into arginine.
There are many studies proving that extra arginine in the body boosts nitric oxide (NO) production.
More NO means more blood flow to working muscles, enabling them to work longer and harder.
Ultimately, this results in more muscle gain.
What Does Citrulline Malate Do?
We have already mentioned that endurance athletes have been taking supplemental citrulline malate for years to help increase their endurance levels.
Weightlifters are now discovering that this powerful amino acid can also reduce fatigue and boost muscle gain.
In fact, this supplement has these beneficial effects in prolonged bouts of both aerobic and anaerobic exercise.
As we discussed above, extra citrulline steps up the urea cycle, meaning that ammonia is taken out of the body before it can contribute to a feeling of fatigue.
We also saw that the kidneys convert citrulline into arginine, which in turn increases the body’s levels of nitric oxide.
It is this nitric oxide that allows muscles to pump harder for longer.
Why, then, don’t we just supplement l-arginine?
Supplementing directly with arginine might seem like the logical thing to do to increase arginine levels.
However, once in the body, arginine supplements are actually broken down and then rebuilt again at a later time when arginine is needed.
After taking an arginine supplement there will be a short spike in arginine plasma levels (the amount of arginine in the blood), but no long-term rise.
Taking citrulline, though, increases both arginine and ornithine plasma levels.
And, even better, arginine plasma levels are raised over a long period as a result of citrulline supplementation, instead of just spiking.
In addition, citrulline doesn’t bring on the stomach upsets and diarrhoea that arginine and ornithine supplements are well known for either, so you can get more into the body without rejection.
Now let’s take a look at some of the specific citrulline malate benefits.
Reduced Muscle Soreness
In a study, published in The Journal of Strength and Conditioning Research, scientists gave male athletes either a placebo or 8g of citrulline malate per day for 7 days.
They found that the supplement boosted the number of reps the men could perform in the final 14 sets of 16 sets of bench presses.
It also reduced muscle soreness 24 and 48 hours later by an average of 40 percent.
In another study, 18 men who had been complaining of fatigue but had no official diagnosis were given a supplement of 6g citrulline malate per day over 22 days.
The study showed that the men reported less fatigue while supplementing.
Increased Training Volume
As reported above, men who had been given 8g of citrulline malate each day for 7 days were able to perform more reps in the final 14 of 16 sets of bench presses.
This could, of course, lead to gains in muscle growth because of the increased training volume.
Lowered Blood Pressure
Over a period of six months, heart failure patients were given a 3g daily dose of citrulline malate, in a different study.
Their cardiac function was seen to improve and their blood pressure came down.
Another group of patients took 8g of arginine daily, they had similar improvements.
Citrulline malate offers the same results as more than double the amount of arginine.
Another study lasting seven days found that citrulline increased blood flow in overweight, but otherwise healthy, male participants.
However, the dose of 5.6g daily did not affect the blood pressure itself.
The effects of citrulline on the blood flow have also led to it being used successfully to treat erectile dysfunction.
Increased Growth Hormone
When young men were given a single dose of 6g of citrulline, before performing in an exercise test, their growth hormone levels after exercise were boosted.
Levels were found to have risen by 66.8 percent, in this study.
This study noted an increase in nitrite which implies that NO had also increased.
Boosted Immune System
A study of male cyclists, appeared to show that 6g of citrulline could have a beneficial effect on the post workout immune system.
After supplementation and then a cycling stage, the men were found to have increased intracellular nitrate concentrations.
This usually leads to an oxidative burst in which many different types of cell rapidly release chemicals which clean up bacteria.
More and more studies are uncovering the positive effects of citrulline malate supplementation.
If you are keen to get started and discover how it can help you, read on for advice on dosing and when to take the supplement for the best effect in your regime.
How Much Citrulline Malate Should You Consume?
What is the recommended dosage of citrulline malate?
Studies in humans have shown noticeable effects from as little as 3g of citrulline per day.
8g per day has been shown to decrease feelings of fatigue and increase training volume in male athletes.
A dose of 6g has been shown to increase citrulline plasma levels as well as doubling arginine plasma levels and ornithine plasma levels.
Higher doses (of 0.18g per kg of body weight), taken orally, increased citrulline plasma levels by 6-11 times.
But, still only caused arginine and ornithine plasma levels to double from their usual amounts.
Citrulline doses from 5-10g per day appear to cause linear increases in arginine plasma levels.
But with higher doses, the effect diminishes, so that taking a higher dose such as 15g is unlikely to increase arginine levels significantly.
Citrulline is absorbed by a wider variety of transporters in the gut than arginine.
This means that more of the substance actually makes it into the body to be converted into arginine, than if you take an arginine supplement.
Doses of more than 10g of arginine are well-known for causing diarrhoea and an upset stomach.
However, because citrulline is well absorbed it simply doesn’t have these unpleasant effects, even in doses as high as 15g.
There are no standardised citrulline malate dosages.
When deciding on your dose, take into account the information above, and factor in your size, health, and your reason for taking the supplement.
Then start on a low dose and build up slowly while observing the effects on your body.
You may decide to stop at a lower dose than you anticipated because the benefits are clear from that dose.
Foods That Contain Citrulline Malate
Not surprisingly, watermelon (latin name – citrullis vulgaris) is a great food source of citrulline, with just over 2mg of citrulline per 1g of watermelon.
The citrulline content is highest in the rind, but if eating the rind isn’t for you, scraping off the fruit close to it is the next best thing.
Look out for ‘watermelon water’ in energy drinks, for another source of citrulline.
Energy drink companies have been quick to recognise the potential of this refreshing fruit.
Pumpkins and cucumbers also contain citrulline but the doses are very low.
Other foods that contain small amounts of citrulline are: red meat, chickpeas, salmon, peanuts and walnuts and dark chocolate.
None of these foods contains enough citrulline to raise your levels enough to see exercise benefits, so if you want to up your game a supplement is the way to go.
When Should You Take Citrulline Malate?
When is best to consume citrulline malate?
Just as there is no official dosage of citrulline malate, there is no official advice on the best times to take the supplement.
For weight-lifting, where a boost in power is needed during intense training or for a competition it may be beneficial to take your dose about an hour before your gym session.
Although stomach problems are rarely reported as a side effect of taking this supplement.
However, if you do notice any problems, you could split your dose into half pre and half post workout.
For bodybuilding, the timing of ingestion is less critical.
As discussed earlier, citrulline tends to raise arginine plasma levels over a long period.
It is the arginine plasma levels that promote NO production and boost training volume, meaning that you will benefit from the muscle building effects of citrulline no matter when you take it.
Side Effects of Citrulline Malate
What are the side effects of taking citrulline malate?
There are no known side effects of taking citrulline malate in one-off doses of up to 15g for healthy adults.
Studies using daily doses of up to 3g for a period of six months reported no adverse effects, and up to 8g per day has been taken for three weeks with no reported side effects.
Citrulline malate is generally considered to be safe for healthy adults.
There is currently not enough evidence to show safety for pregnant women or children.
Because citrulline can affect the blood vessels and blood pressure, it shouldn’t be taken alongside drugs used to treat hypertension.
Similarly, nitrates such as angina medications and PDE-5 inhibitors like Viagra should not be taken with citrulline malate.
They can cause severe drops in blood pressure that could be fatal.
Do You Need to Cycle Citrulline Malate?
Is it recommended to cycle citrulline malate?
As citrulline malate is generally thought to be safe, there is no evidence that it needs to be cycled.
So there we have it – citrulline malate can increase muscle pumps and improve muscle gain.
It can reduce the soreness of muscles and even boost the post workout immune system – and all without any apparent side effects.
If you really want to get every last rep out of your sets, then citrulline malate could be your new favourite supplement.