Citrulline is a non-essential amino acid like L-arginine. L-arginine is supposed to increase nitric oxide production, which in turn improves energy production. However, many experts are of the view that citrulline can also be used in place of L-arginine. Citrulline is a better choice because your body can absorb it more efficiently as compared to L-arginine.
Does it help power up your workout sessions? Some studies have confirmed that supplementing with citrulline may improve muscle endurance and aerobic performance. It is also likely to relieve muscle soreness. What it means is that even if L-citrulline does not lead to a significant increase in power, it certainly helps relieve post-workout soreness that enables you to approach your next workout with equal intensity.
More about Citrulline Malate
Citrulline Malate is actually a combination of L-citrulline and Malate. It means that it combines L-citrulline and malic acid. It was first introduced in the late 70’s when a product called Stimol became popular to treat physical and mental fatigue in post-surgery and geriatric patients.
Stimol was also found to improve muscle performance in people suffering from a condition called asthenia, which is characterized by a lack or loss of body strength.
Using that knowledge, many supplement manufacturers now include citrulline malate in their products to help fight post-workout fatigue.
How It Works
Citrulline affects your body in many different ways. Most of its benefits come from the claim that it helps dilate blood vessels. With vasodilation, your blood circulation will increase but your blood pressure will come down. Your body uses citrulline to produce arginine, which is then changed in nitric oxide. Nitric oxide is responsible for that vasodilation known for reducing muscle soreness and fatigue.
The interesting thing is that taking citrulline is much better than taking arginine, because your body absorbs both amino acids differently. It may also help with muscle building because it increases protein synthesis through the stimulation of a signaling pathway. Here are some other potential benefits of citrulline:
- Helps your blood vessels widen, which is beneficial for people suffering from hypertension. The widening of your blood vessels ensures improved blood flow to tissues. The benefit may come when you are already at risk of heart disease – you also need to consume a larger dose for several days to see the effects.
- Lowers blood pressure. Again, the benefit is more evident in people having high blood pressure. Many studies have found that people suffering from hypertension may have their blood pressure reduced by 4-15% after taking citrulline supplements for eight weeks. Some small studies have also shown that citrulline supplements may reduce blood pressure by 6-16% in healthy adults as well.
- Increases the levels of growth hormone (GH). Studies have noticed that there may be an increase in GH levels after exercise if you are on citrulline supplementation. With an increase in blood circulation and growth hormone, there may also be an improvement in your sexual performance. Studies show that citrulline supplementation may be associated with improved erections in men suffering from erectile dysfunction.
- Boosts exercise performance. Most athletes opt for citrulline supplements mainly to see an improvement in exercise performance. Studies have confirmed that it may increase endurance and stamina, but you may not experience benefits after a single dose. Regular use may lead to an increase in the oxygen content in your muscle tissue, which in turn helps improve exercise performance. Your body will be able to use more oxygen, and an increase in oxygen will directly affect your exercise performance in a positive way.
Interestingly, there is some good scientific evidence to support the use of citrulline malate for a boost in power and endurance. Here are a few findings to make it clear:
- In a group of female masters tennis players, taking 8 grams of citrulline malate 60 minutes before exercise improved both cycling power and maximal grip strength. Source
- When a group of 15 women took 8 grams of citrulline malate an hour before lifting weights (6 sets of the bench press and leg press to failure), they could complete significantly more reps in both exercises (Source). What’s more, the women also reported lower overall feelings of exertion when taking citrulline malate.
- In a similar study, a group of resistance-trained men performed three sets each of chin-ups, pull-ups, and push-ups to failure (Source). Taking 8 grams of citrulline malate before exercise led to a significant increase in the number of reps performed for each exercise.
You can increase your intake of citrulline by including certain foods in your diet. For instance, studies show that you can get a good dose of citrulline from foods like pumpkins, watermelon, bitter melon, cucumber, and gourds.
The Other Side of the Picture
It is worth mentioning that the effects of citrulline are dose-dependent. It means that you are not going to see good results if you are not taking enough daily. Moreover, how your body metabolizes it determines the effects you experience. It is for this reason that some studies have also found mixed results. For instance, you may certainly experience improvement in endurance for aerobic and anaerobic exercise if you take more than 3,000mg of L-citrulline a day.
- In an incline walking test until failure in otherwise healthy persons, 3 or 9g citrulline (acutely or over 24 hours, respectively) appeared to actually reduce time to exhaustion (0.8%, a clinically irrelevant degree) and suppressed the exercise-induced increase in insulin. Other biomarkers tested were unaltered, although heart rate trended to decrease with 3g citrulline.
Similarly, you need to take large doses to make L-citrulline bring any changes the levels of L-arginine in your body. For instance:
- A double-blind randomized placebo-controlled 2-way crossover study was employed. Twenty-two trained males consumed 2.4 g/day of L-citrulline or placebo orally for 7 days. On Day 8 they took 2.4 g of L-citrulline or placebo 1 h before a 4-km cycling time trial. Time taken to complete the 4 km cycle, along with power output/VO2 ratio (PO/VO2), plasma nitrite and nitrate (NOx) and amino acid levels, and visual analog scale (VAS) scores, was evaluated. L-Citrulline supplementation significantly increased plasma L-arginine levels and reduced completion time by 1.5 % (p < 0.05) compared with placebo. Moreover, L-citrulline significantly improved subjective feelings of muscle fatigue and concentration immediately after exercise. Source
Bodybuilders would have to increase the dose even further to experience the beneficial effects of L-citrulline. For instance:
- Supplementation with 8g citrulline (as malate, with 10g sugar that was also used in placebo condition) during a weight lifting protocol (perform as many reps as possible until fatigue for multiple sets) noted that citrulline was able to delay fatigue and promote more reps performed per set for all sets except the first two and reduced post-workout muscle soreness. Source
If you take less than this, you may not find l-citrulline works for you. Interestingly, Citrulline Malate can be a hit or miss for many athletes. It means that even when you take enough, you may not find Citrulline Malate work better than a placebo. For instance:
- In one trial, 12 grams of citrulline malate taken 60 minutes before exercise failed to improve cycling performance in a group of well-trained men. Source
It is supposed that L-citrulline almost always helps relieve muscle soreness, but not all studies have found the same. For instance:
- In a study, 6 grams of citrulline malate taken before a workout had no effect on post-exercise muscle soreness or various markers of muscle recovery. Source
You may not always notice an improvement in endurance and power. For instance:
- Eight grams of citrulline malate taken 40 minutes before training had no effect on performance during 5 sets to failure on the bench press (Source). Nor did it have any positive effect on subjective measures of focus, energy or fatigue.
Due to these contradictions, it is not possible to say that citrulline malate will always help power up your workout sessions, especially when you do not take enough. Most studies have used no less than 8g of citrulline malate. The problem is that most supplements will never provide you with this much per serving. You will have to spend top dollar to buy a supplement that contains enough citrulline malate, but even then, there is no guarantee that it will work for you.
As you can see, citrulline malate or L-citrulline is supposed to help you in many ways, but you need to bear in mind that it is not safe to take citrulline malate in certain conditions. If you have some gastrointestinal problems, it is better to avoid citrulline malate in the first place.
You should also avoid it if you are already taking some medications for a preexisting condition. You should avoid it when you are taking nitrates for heart disease, or taking drugs for erectile dysfunction. You need to ensure that you do not take these supplements when you are already taking blood pressure medication.
Similarly, you need to avoid it when you are pregnant or breastfeeding. It can interact with prescription and OTC drugs, so it is better to talk to your doctor before you decide to include any citrulline supplement in your routine.
The fact of the matter is that the research on citrulline malate offers inconsistent results. Some studies have certainly found an improvement in fatigue and performance, while others have observed no effect at all. It is also important to bear in mind that most of the studies with positive benefits have measured the change in performance after a single dose, which means there is no real information available on how citrulline supplementation will help over an extended period.
Therefore, it is not possible to say that citrulline malate is always beneficial, but if you are the experimental type, you should certainly give it a try but ensure that you are getting enough from each serving of your supplement.
Disclaimer: Our reviews and investigations are based on extensive research from the information publicly available to us and consumers at the time of first publishing the post. Information is based on our personal opinion and whilst we endeavour to ensure information is up-to-date, manufacturers do from time to time change their products and future research may disagree with our findings. If you feel any of the information is inaccurate, please contact us and we will review the information provided.