Affiliate Disclosure
As an Amazon Associate and iHerb affiliate, we earn from qualifying purchases. This post contains affiliate links, and if you make a purchase through these links, we may receive a commission at no additional cost to you. This does not affect the objectivity of our review.
Quick Answer
Citrulline malate is a supplement that combines an amino acid (citrulline) with malate (a salt of malic acid), and is sold primarily as a pre-workout supplement. Studies consistently show that it can support improved blood flow and reduce feelings of muscular fatigue during resistance and endurance training. It is not a substitute for caffeine or creatine, but rather a supplement that works through a different mechanism – increasing the body’s available nitric oxide.
What It Is and How It Works
Citrulline is an amino acid that the body converts into arginine, from which nitric oxide – a molecule that dilates blood vessels – is produced. In practice, taking citrulline may raise blood arginine levels more effectively than taking arginine itself, due to better absorption in the intestine.
The “malate” form adds malic acid, which is involved in the cellular energy production cycle (the Krebs cycle). The combination is intended to support both blood vessel dilation and more efficient clearance of metabolic byproducts like ammonia.
Evidence-Based Benefits
- Reduced feelings of muscular fatigue: Studies consistently show that taking citrulline malate before a workout reduces perceived exertion and allows for additional reps in resistance training.
- Improved blood flow and muscle “pump”: Preliminary studies point to increased blood flow to active muscles, though the strength of this effect varies between individuals and between studies.
- Support for endurance performance: The evidence here is mixed – some studies show a slight improvement in prolonged endurance performance, while others found no significant difference compared to placebo.
- Reduced delayed-onset muscle soreness (DOMS): Preliminary studies point to some reduction in muscle soreness after exertion, but further research is needed to confirm this finding.
Dosage and Timing
The dosage commonly used in studies on citrulline malate ranges from 6 to 8 grams, given as a single dose about 60 minutes before the workout. Some studies have also examined higher doses, but these are sometimes associated with gastrointestinal side effects.
It’s important to note: many products on the market contain less than the dose tested in studies (sometimes only 1-3 grams), so it’s recommended to check the label carefully. Consult a doctor or sports dietitian before starting use, especially if you take medications or have an existing health condition.
Safety and Side Effects / Who Should Be Cautious
Citrulline malate is considered safe for healthy populations at the doses studied, but there are several points to note:
- Gastrointestinal discomfort – nausea, diarrhea, or abdominal pain, mainly at higher doses.
- Possible interaction with blood pressure medications – due to its effect on blood vessel dilation, consult a doctor if you take blood pressure medications or erectile dysfunction medications (such as PDE5 inhibitors).
- Insufficient safety research exists regarding pregnant or breastfeeding women, so it is recommended to avoid use without explicit medical guidance.
- Children and teenagers – most studies were conducted on adults, and there isn’t enough data to recommend use in younger populations.
Who It’s Suitable For
- People doing resistance (strength) training who want to perform additional reps before fatigue sets in.
- Endurance athletes interested in exploring possible performance support, while understanding that the evidence in this area is mixed.
- Healthy individuals, without blood pressure issues or relevant medications, looking for a caffeine-free pre-workout supplement.
- Those sensitive to caffeine who want an alternative to stimulant-based pre-workout supplements.
How to Choose a Quality Product
Look for a product that explicitly states “L-Citrulline Malate” with a known ratio (typically 2:1 citrulline to malate), rather than just a “Citrulline Blend” without specified amounts. It’s preferable to choose a brand with third-party testing, such as an NSF Certified for Sport or Informed-Choice seal, especially if you’re a competitive athlete subject to doping tests.
Where to Buy
You can find a range of good-quality citrulline malate supplements at competitive prices through the following links:
FAQ
Is citrulline malate better than plain arginine?
Studies show that citrulline may raise blood arginine levels more effectively than taking arginine directly, thanks to better absorption in the intestine.
Can citrulline malate be combined with creatine?
Yes, there’s no evidence of a negative interaction between the two, and they work through different mechanisms – which is why combining them is common in pre-workout supplements.
How long before a workout should it be taken?
Most studies used a timing of about 60 minutes before the workout, to allow for full absorption.
Is there a difference between powder and capsule supplements?
Not in terms of effectiveness, but powder generally makes it more convenient to reach the higher doses tested in studies (6-8 grams) without needing to take a large number of capsules.
Is citrulline malate suitable for vegetarians and vegans?
In most cases, yes, but it’s recommended to check the label, as some capsules may be made from animal-derived gelatin.
Disclaimer: The information in this article is intended for informational purposes only and does not constitute medical, nutritional, or diagnostic advice. Consult a doctor or a certified sports dietitian before starting use of any dietary supplement, especially if you have an existing medical condition, take medications, or are pregnant or breastfeeding.