Drinking watermelon typically refers to consuming blended or juiced watermelon flesh, sometimes called watermelon juice or watermelon water. Because the fruit is more than 90% water, it blends into a drinkable liquid with minimal effort. The practice has gained popularity as a hydration strategy, a post-workout recovery drink, and a way to get nutrients from fruit in a convenient form.
What Watermelon Juice Actually Contains
One cup of watermelon provides 12 milligrams of vitamin C, 865 international units of vitamin A, and 170 milligrams of potassium. When you blend or juice it, most of those nutrients carry over into the liquid. Watermelon is also one of the richest food sources of lycopene, the same antioxidant pigment found in tomatoes, and it contains a notable amount of an amino acid called L-citrulline, which plays a role in blood flow and muscle recovery.
What you lose in the transition from whole fruit to juice is fiber. The Cleveland Clinic notes that fiber is the biggest casualty of juicing any fruit. Whole watermelon gives you more of a full-belly feeling because of the fruit’s solid flesh, which means you’re less likely to feel hungry again shortly after. Drinking it as juice delivers the vitamins and water content but skips that satiety benefit, so the sugar hits your bloodstream faster and you may find yourself reaching for food sooner.
Hydration Beyond Plain Water
The simplest reason people drink watermelon is hydration. With its water content above 90%, it functions almost like flavored water that happens to carry vitamins and minerals along for the ride. About 20% of daily hydration comes from food rather than beverages, and watermelon is one of the most efficient foods for contributing to that intake.
After exercise or heavy sweating, watermelon juice paired with a small pinch of salt can help replenish both fluids and electrolytes. The natural sugars in the juice restore carbohydrate stores while the potassium supports electrolyte balance. It won’t replace a full meal after intense training, but as a quick rehydration tool on a hot day or after a moderate workout, it does the job well.
Effects on Muscle Soreness
L-citrulline, the amino acid naturally present in watermelon, is the ingredient behind most of the exercise-related claims. Your body converts it into another amino acid that helps produce nitric oxide, a molecule that widens blood vessels and improves circulation. Better blood flow means muscles receive oxygen and clear waste products more efficiently during recovery.
A study published in the Journal of Agricultural and Food Chemistry tested this directly. Seven athletes drank about 500 milliliters (roughly 17 ounces) of natural watermelon juice containing 1.17 grams of L-citrulline before a maximum-effort cycling test. Both natural and enriched watermelon juice reduced muscle soreness 24 hours later and helped lower recovery heart rate compared to a placebo. That’s a meaningful difference from a single glass of juice, though the effect is modest compared to dedicated supplements that deliver higher doses.
Blood Pressure and Heart Health
Several controlled trials have examined watermelon extract’s effect on blood pressure, particularly in people who already have elevated readings. In studies involving middle-aged adults with hypertension and postmenopausal women, six weeks of watermelon extract (delivering about 4 grams of L-citrulline daily) produced measurable reductions in both systolic and diastolic blood pressure. The mechanism is straightforward: L-citrulline boosts nitric oxide production, which relaxes artery walls and lowers the pressure your heart has to pump against.
The results are more impressive in people with existing blood pressure concerns than in healthy individuals. One trial gave healthy postmenopausal women two 360-milliliter servings of watermelon juice daily for four weeks. Their circulating lycopene levels rose significantly, but their blood pressure and arterial stiffness measurements didn’t change. So if your blood pressure is already normal, drinking watermelon juice is unlikely to push it lower. If it’s elevated, there’s reason to think regular intake could offer a small benefit alongside other lifestyle measures.
Natural Diuretic Properties
Watermelon has a long history in traditional medicine as a natural diuretic, and animal research has confirmed this effect. In a study using rat models, watermelon pulp extract increased urine output and raised urinary sodium and chloride levels, which is how pharmaceutical diuretics work as well. For most people, this translates to a mild increase in urination after drinking watermelon juice, which is normal and not a concern.
This diuretic quality is worth keeping in mind if you have kidney problems. People with chronic kidney disease often need to limit potassium and fluid intake, and watermelon juice delivers both in significant amounts. The same properties that make it a good hydration tool for healthy people can be counterproductive when kidneys aren’t filtering efficiently.
Juice vs. Whole Watermelon
Blending watermelon at home retains more of the fruit’s pulp and some fiber compared to store-bought juice that’s been strained. If you’re making it yourself, leaving the pulp in gives you a thicker drink that’s closer nutritionally to eating the whole fruit. Store-bought watermelon juice, especially varieties labeled “watermelon water,” is often filtered and may contain added sugars.
The sugar content is the main trade-off to consider. A cup of watermelon contains about 9 grams of natural sugar, which is relatively low for fruit. But when you juice it, it’s easy to use two or three cups’ worth of fruit per glass, concentrating the sugar without the fiber that would slow its absorption. Drinking a moderate portion, roughly one cup’s worth of fruit blended with some ice, gives you the hydration and nutrient benefits without a large sugar spike. Treating it as a complement to whole fruits and vegetables rather than a replacement keeps the balance in your favor.