At a glance:
- Watermelon contains L-citrulline, which supports nitric oxide production and may ease post-workout muscle soreness.
- 300–500 g of watermelon before a workout provides fast-acting carbohydrates and supports hydration.
- Watermelon is low in calories but rich in lycopene and vitamin C.
- The evidence is promising, but most studies have small samples – watermelon complements a balanced diet rather than replacing it.
Watermelon is one of the more extensively studied natural foods that may support both athletic performance and recovery. More than 90% of watermelon is water, making it a good source of hydration if you train during the summer months. Its value also lies in its bioactive compounds – particularly the amino acid L-citrulline.
Why is watermelon particularly beneficial for athletes?
For athletes, watermelon offers an unusual combination: high water content, natural sugars for quick energy and L-citrulline to support muscles. In a study where endurance athletes drank 500 ml of unpasteurized watermelon juice an hour before a workout, muscle soreness after 24 hours and heart rate during recovery were significantly lower than in the control group (Tarazona-Díaz et al., 2013). However, the sample was small (seven sprint cyclists), so the findings cannot readily be generalized to all sports.
According to the TAI nutrition database, 100 g of fresh watermelon contains approximately:
- Energy: 30 kcal
- Carbohydrates: 7.5 g (mainly glucose and fructose)
- Dietary fiber: 0.4 g
- Vitamin C: ~8 mg (≈10% of the recommended daily intake)
- Lycopene: 4–6 mg
- Potassium: ~112 mg
- L-citrulline: ~150–200 mg (Rimando & Perkins-Veazie, 2005)
How does L-citrulline affect athletic performance?
L-citrulline is an amino acid that the body converts first into L-arginine and then into nitric oxide (NO). Nitric oxide dilates blood vessels, improving the delivery of oxygen and nutrients to muscles and speeding up the removal of metabolic waste products. This mechanism is why citrulline has been studied in both endurance and strength athletes.
Studies using citrulline malate (a synthetic form) have shown that an 8 g dose reduces post-workout muscle soreness and increases rep count during strength training (Pérez-Guisado & Jakeman, 2010). The amount of citrulline obtained from watermelon typically falls within the 300–600 mg range – less than the supplement doses used in studies, but obtaining it from food is safe and affordable. If you are considering taking citrulline as a supplement, first read the guide to supplements for athletes to understand dosage and safety in a broader context.
When and how much watermelon should you eat around training?
You can incorporate watermelon at several points in your training routine:
Before a workout (30–60 min)
300–500 g of fresh watermelon or 500 ml of juice partially replenishes glycogen stores, provides fluid and delivers a readily absorbed energy boost without leaving your stomach feeling heavy.
During a workout
Watermelon water (blended watermelon with nothing added) works as a light energy drink during short aerobic sessions if you prefer to avoid sports drinks containing artificial flavorings and sugars.
After a workout
Watermelon replaces lost fluid and electrolytes (potassium). For the best recovery, pair it with a protein-rich food, as watermelon contains very little protein.
A food diary gives you the most accurate picture of how much you eat each day and your nutrient intake – why use a food diary offers a practical introduction to building this habit.
Can watermelon replace creatine or other supplements?
No. Watermelon is a healthy food, not a complete dietary supplement. The amount of citrulline in 500 g of watermelon (≈750–1000 mg) is several times lower than the doses shown to be effective in clinical studies. If you are a strength athlete looking for an evidence-based supplement to build muscle mass and strength, it is worth reading how to use creatine – creatine is one of the few supplements whose effectiveness has repeatedly been demonstrated in large studies.
Lycopene, which watermelon contains in abundance, is a potent antioxidant. EFSA has assessed the safety of dietary lycopene and found that typical amounts consumed through food are safe and may help reduce oxidative stress (EFSA, 2008). Intense training increases free radical production, making antioxidant-rich foods – including watermelon – a natural part of an athlete’s diet.
In summer, watermelon also offers a welcome change – as Oh, that Ott reminds us, seasonal foods are often the best choices for both flavor and nutritional value.
References
- Tarazona-Díaz MP, Alacid F, Carrasco M, Martínez I, Aguayo E. (2013). Watermelon juice: potential functional drink for sore muscle relief in athletes. J Agric Food Chem. 61(31):7522–7528. PMID: 23862566
- Pérez-Guisado J, Jakeman PM. (2010). Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. J Strength Cond Res. 24(5):1215–1222. PMID: 20386132
- Rimando AM, Perkins-Veazie PM. (2005). Determination of citrulline in watermelon rind. J Chromatogr A. 1078(1–2):196–200. PMID: 16007998
- EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS). (2008). Lycopene as a food colour. EFSA Journal. 6(1):674. DOI: 10.2903/j.efsa.2008.674
Frequently asked questions
How much watermelon do you need to eat to get enough L-citrulline?
Studies used 500 ml of unpasteurized watermelon juice (equivalent to approximately 500–600 g of watermelon). This provides 750–1200 mg of L-citrulline, a realistic amount to obtain from food, but less than the supplement doses used in clinical studies (6–8 g).
Is watermelon juice a good choice before a workout?
Yes. Drinking unpasteurized watermelon juice 30–60 minutes before a workout provides fast-acting carbohydrates, supports hydration and supplies L-citrulline. Avoid excessive amounts if you have a sensitive digestive system.
Does watermelon help with muscle recovery?
One small study (Tarazona-Díaz et al., 2013) showed that watermelon juice reduced post-workout muscle soreness within 24 hours. The evidence is promising but limited – watermelon is a useful addition, not a substitute for medical treatment.
Is watermelon high in sugar?
100 g of watermelon contains ~7.5 g of carbohydrates, mostly glucose and fructose. However, its high water content keeps its glycemic load low (GL ≈ 4 / 100 g), so moderate amounts are also suitable for athletes who pay attention to managing their blood sugar.
Is watermelon suitable if you are watching your weight?
Yes. Watermelon is one of the lowest-calorie fruits (≈30 kcal / 100 g), and its high water content helps you feel full. However, a large portion (over 700 g) adds a substantial amount of sugar, so it is worth keeping track of your total daily calorie intake.
Come and train! ArtGym
