The Powerhouse Amino Acid for Fitness and Health 

Citrulline is a naturally occurring amino acid that plays an essential role in the urea cycle, the body’s process of removing ammonia and toxins from the blood. It’s not only found in the body, but also in various foods, especially watermelon, which has earned the fruit the nickname "nature’s citrulline source" (Schiavone et al., 2015). 

There are two main types of citrulline supplements: L-citrulline and citrulline malate. The primary difference lies in the addition of malic acid in citrulline malate, which enhances the effects of citrulline on energy production (Hickson et al., 2010). 

How Does Citrulline Work in the Body? 

Once ingested, citrulline is converted into arginine, another amino acid, in the kidneys. Arginine is a precursor to nitric oxide (NO), a molecule that plays a vital role in vasodilation — the process of widening blood vessels. By increasing nitric oxide levels, citrulline helps improve blood flow, which delivers more oxygen and nutrients to muscles during exercise, ultimately supporting endurance, strength, and recovery (Bailey et al., 2010). 

The Key Benefits of Citrulline 

One of the many benefits Citrulline offers to athletes: 

1. Enhanced Exercise Performance and Endurance 

Citrulline has been shown to improve aerobic and anaerobic endurance. By increasing blood flow, oxygen, and nutrient delivery to muscles, citrulline can help you perform better during high-intensity workouts, longer cardio sessions, or weightlifting routines. Many athletes take citrulline to delay muscle fatigue, allowing them to push harder for longer periods (Bescós et al., 2012). 

2. Reduced Muscle Soreness (DOMS) 

Delayed onset muscle soreness (DOMS) can be a major setback after intense workouts, especially when trying to recover for your next training session. Research suggests that citrulline supplementation can help reduce DOMS and promote quicker recovery between workouts, making it a go-to for athletes and fitness enthusiasts who need to get back to training sooner (Suzuki et al., 2013). 

3. Improved Blood Flow and Oxygen Delivery 

Citrulline increases nitric oxide production, which helps widen blood vessels and improve circulation. This enhanced blood flow means your muscles get more oxygen and nutrients, which not only boosts performance but also aids in the recovery process by flushing out metabolic waste products like lactic acid (Bescós et al., 2012). 

4. Support for Heart Health 

Because citrulline helps boost nitric oxide levels, it can play a role in improving vascular health. Nitric oxide has been shown to help relax blood vessels, improve circulation, and lower blood pressure. As a result, citrulline may be beneficial for heart health, especially in people with hypertension or poor circulation (Larsen et al., 2013). 

5. Improved Erection Quality (for Men) 

Due to its effect on nitric oxide, citrulline has also been linked to improved erectile function in men. Increased nitric oxide production helps relax the blood vessels in the genital area, potentially supporting better blood flow and better erectile performance (Cortes et al., 2011).