Know2eat

Watermelon

Citrullus lanatus

Also known as Seedless watermelon, Sugar baby watermelon

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A large cucurbit fruit that is over nine-tenths water by weight, with red flesh coloured by lycopene. The rind and the flesh both contain the amino acid citrulline, named after this species.

Muscle & Physical PerformanceHeart HealthCirculation

Potential health benefits

Best supported: Limited

Ordered by how well the human research supports them — strongest first. A rating describes the state of the evidence, not how impressive the food is. How we rate evidence.

Exercise recovery

Muscle & Physical Performance
Limited evidence

A small number of trials report reduced muscle soreness after exercise with watermelon juice. The studies are few, small and short, and findings have not been independently repeated at scale.

Limited evidence. Early human work, or mostly lab and animal research.

3 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Healthy blood pressure

Heart Health
Limited evidence

Some trials of watermelon or its citrulline report small reductions in blood pressure, particularly central aortic pressure. The trials are small, several use concentrated citrulline rather than fruit, and results are not consistent.

What may be going on: Citrulline is converted to arginine, the substrate for nitric oxide synthesis, which relaxes blood vessels.

Limited evidence. Early human work, or mostly lab and animal research.

2 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Endothelial function

Circulation
Insufficient evidence

Watermelon is often promoted for circulation on the strength of its citrulline. Trials measuring vascular function after eating the fruit are too few and too small to support a dependable conclusion.

Insufficient evidence. Not enough human research to say anything useful yet.

4 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Ask about Watermelon

Ask about Watermelon

Answers are written only from the entries on this page — the same nutrients, compounds, claims and citations you can read above. Nothing is added from outside the database, and every answer lists what it was built from.

AI explanations are not switched on for this site, so there is nothing to ask here. Everything above is read straight from the database and does not need them.

Key nutrients

Nutrient content per 100 grams
NutrientAmount% DV
Macronutrients
Calories30 kcal2%
Protein0.61 g1%
Total fat0.15 g0%
Carbohydrate7.55 g3%
Fibre0.4 g1%
Total sugars6.2 g—
Water91.5 g—
Fats
Saturated fat0.016 g0%
Monounsaturated fat0.037 g—
Polyunsaturated fat0.05 g—
Cholesterol0 mg0%
EPA (omega-3)0 g—
DHA (omega-3)0 g—
DPA (omega-3)0 g—
Linoleic acid (omega-6)0.05 g—
Vitamins
Vitamin A28 µg3%
Vitamin C8.1 mg9%
Vitamin D0 µg0%
Vitamin E0.05 mg0%
Vitamin K0.1 µg0%
Thiamin (B1)0.033 mg3%
Riboflavin (B2)0.021 mg2%
Niacin (B3)0.178 mg1%
Pantothenic acid (B5)0.221 mg4%
Vitamin B60.045 mg3%
Folate3 µg1%
Vitamin B120 µg0%
Choline4.1 mg1%
Minerals
Calcium7 mg1%
Iron0.24 mg1%
Magnesium10 mg2%
Phosphorus11 mg1%
Potassium112 mg2%
Sodium1 mg0%
Zinc0.1 mg1%
Copper0.042 mg5%
Manganese0.038 mg2%
Selenium0.4 µg1%
Other measured compounds
Beta-carotene303 µg—
Alpha-carotene0 µg—
Lycopene4532 µg—
Lutein + zeaxanthin8 µg—
Caffeine0 mg—
Ash0.25 g—

Nutrient values are per 100 g of the USDA reference entry named on this page and vary with variety, growing conditions, storage and preparation.

Source record: Watermelon, raw (USDA FoodData Central, FDC ID 167765).

% DV uses the FDA Daily Values for adults and children aged 4 and over. A dash means no Daily Value has been established for that nutrient.

Bioactive compounds

Compounds present in meaningful amounts. Presence is banded rather than quantified, because whole-food levels vary enormously with variety, growing conditions, storage and preparation.

How preparation changes things

Only effects with real support are listed. If a preparation method is missing, it is because nothing dependable is documented — not because it makes no difference.

Nothing dependable is recorded about how preparation changes this food’s nutritional properties. Rather than guess, this section stays empty.

Things to know

Allergies, interactions and intake concerns. Every food gets this section — a reference where everything is uniformly good is not a reference.

  • Too much

    High FODMAP content

    Watermelon combines excess fructose with the polyols mannitol and sorbitol, making it one of the highest-FODMAP fruits and a common trigger in irritable bowel syndrome.

  • Worth knowing

    High glycaemic index, low glycaemic load

    Watermelon has a high glycaemic index but so little carbohydrate per serving that a normal portion delivers a small glucose load. Lists that flag it as a food to avoid in diabetes usually confuse the two measures.

  • Worth knowing

    Fluid and potassium load in advanced kidney disease

    The potassium concentration is low, but very large quantities deliver both potassium and a substantial fluid volume. Cases of raised potassium have been reported in people on dialysis eating large amounts, and fluid limits also apply.