Watermelon

Watermelon (Citrullus lanatus): A Comprehensive Reference

1. Identity and Botanical Classification

Botanical name: Citrullus lanatus (Thunb.) Matsum. & Nakai (2n=2x=22), belonging to the botanical family Cucurbitaceae. The species is also referenced historically under the synonym Citrullus vulgaris. The name Citrullus derives from the Latin word meaning "small gourd," while the species name lanatus translates to "woolly," a reference to the fine hairs found on some parts of the plant.

Watermelon is a vine-like flowering plant originally from sub-Saharan Africa. It is grown in favourable climates from tropical to temperate regions worldwide. In the year 2020, a production area of 3.05 million hectares was employed for the production of 101 million tons of watermelon throughout the world, with Asia contributing approximately 81% of total production.

Common names: Watermelon is also known by the common names Watermelon Vine, Tsamma Melon, Egusi, Anguria, Melancia, Sandía, Wassermelone, and Pastèque.

Plant morphology: Watermelon plants are sprawling annual vines that can grow several meters long, with broad, lobed leaves of rough texture and large yellow flowers crucial for reproduction. The fruit itself can weigh anywhere from 2 to 60 pounds, depending on the variety. The fruit is characterised by a green rind and juicy, red or yellow flesh filled with seeds.

Common Forms and Preparations

• Fresh flesh (whole fruit): The most common form of consumption worldwide; the red or yellow flesh is eaten raw or chilled.
• Watermelon juice: Watermelon by-products include juice and smoothies, among others. Juice has been used extensively in clinical trials as a functional beverage.
• Watermelon extract / powder (concentrated): The use of concentrated watermelon powder allows for the provision of a greater quantity of L-citrulline and L-arginine in a smaller quantity of product, facilitating the standardisation of the dose compared to the consumption of fresh fruit, thereby improving applicability in clinical studies and regular use as nutraceuticals.
• Rind preparations: The rind has been utilised in some cultures for culinary dishes. Research has also examined rind-derived supplements for their citrulline content.
• Seed oil: Watermelon seed oil is among the by-products derived from the fruit.
• Pickled rind: Watermelon is enjoyed fresh, juiced, pickled, and even grilled.

2. Traditional and Historical Use

Origins in Africa

Watermelon's history dates back 5,000 years to southern Africa, where a tough, drought-tolerant ancestor of watermelon thrived. Although the exact identity of this plant is unknown, it was prized for its ability to store water and was used by indigenous people in the Kalahari Desert region. Speculation exists that, in addition to taking advantage of its water content, people endemic to the region roasted and ate its seeds as a source of nourishment.

Ancient Egypt

Painted reliefs in Egyptian tombs show watermelon in ancient Egypt; one image from the tomb of Chnumhotep near Saqqara is dated to approximately 2500 BCE. Both seeds and paintings of watermelon have been discovered in Egyptian tombs more than 4,000 years old. Some tomb paintings depict an oval-shaped watermelon, indicating the round wild type must have been improved by ancient plant breeders. Watermelons were often placed in the tombs of pharaohs to nourish them in the afterlife, signifying the fruit's vital role in Egyptian culture.

Classical Antiquity: Greeks and Romans

Writings from 400 B.C. to 500 A.D. indicate the watermelon spread from northeastern Africa to Mediterranean countries. The ancient Greek name for the watermelon was the pepon. Physicians, including Hippocrates and Dioscorides, praised its many healing properties. It was prescribed as a diuretic and as a way to treat children with heatstroke by placing the cool, wet rind on their heads. In Pliny the Elder's Historia Naturalis, he refers to watermelon as a "cooling food."

Hebrew and Biblical Traditions

Numbers 11:5 from the Bible references watermelon as one of the foods the Israelites longed for after leaving Egypt. Additionally, ancient manuscripts of Jewish Law record watermelon as one of the items to be tithed and set aside for distribution to priests and the poor.

Spread to Asia and the Islamic World

In Persia, watermelons became a popular dessert fruit, often served chilled with a sprinkle of salt or lime juice. In Europe, watermelons were introduced by the Moors during the Middle Ages and quickly became a favourite among royalty and nobility. In China, watermelons became a popular treat during the summer, often enjoyed during festivals and family gatherings, and were also given as gifts and used in traditional medicine for their cooling properties.

The Americas

In the late 16th century, Spanish colonists first brought watermelon to what is now the Florida and Georgia coast, where Native Americans quickly adopted them into their cultivated fields. Enslaved Africans also brought watermelon seeds with them to South America, the Caribbean, and the U.S. South, further spreading them throughout the New World. By 1576 and 1629, watermelon was being grown in Florida and Massachusetts, respectively.

3. Phytochemical Composition and Key Constituents

Overview of Bioactive Compounds

Sweet dessert watermelon (Citrullus lanatus) is one of the most important vegetable crops consumed throughout the world. The chemical composition of watermelon provides both high nutritional value and various health benefits. A catalog of 1,679 small molecules occurring in watermelon has been identified and characterised.

L-Citrulline

Watermelon is a naturally rich source for the non-protein α-amino acid citrulline, which has been reported to have antioxidant and vasodilatory activity. Citrulline was first isolated from watermelon by the Japanese researchers Yotaro Koga and Ryo Odake in 1914 and further validated in 1930.

L-citrulline was first isolated from watermelon (Citrullus lanatus), giving L-citrulline its name. Watermelon is the major source of L-citrulline, and several factors can impact its concentration, including environmental factors such as drought stress and high light intensity, and physiological aspects such as cultivar, genotype, flesh colour, and fruit anatomy.

The distribution of L-citrulline across fruit parts has been quantified. The content of L-citrulline in the rind ranges from 0.764 to 1.277 mg/g, which is greater than that of L-citrulline in watermelon flesh (0.580 to 1.103 mg/g) and seeds (0.179 to 0.214 mg/g, dry weight). The highest citrulline content is noted in orange-fleshed genotypes, followed by yellow-fleshed types, while the lowest content is observed in pink and red-fleshed genotypes. Both the rind and flesh of watermelon contain citrulline at concentrations of 1–3 mg citrulline per gram of fresh tissue.

Lycopene

Watermelon is one of the few foods rich in lycopene, a non-provitamin A carotenoid that has up to twice the antioxidant capacity of β-carotene in vitro. Epidemiological studies suggest lycopene may have protective effects. The mean lycopene concentration of watermelon (4,868 μg/100 g) is approximately 40% higher than the year-round mean for raw tomato (3,025 μg/100 g).

Lycopene's chemical structure, with 11 double conjugated bonds (compared with 10 in lutein or 9 in beta-carotene), gives it a higher capacity to neutralise reactive oxygen species such as singlet oxygen. Lycopene, a fat-soluble carotenoid, is one of the most abundant and important carotenoids and has potent antioxidant activity.

Cucurbitacins

Cucurbitacins, a broad family of bitter-tasting compounds in watermelon, have drawn interest for their anti-oncogenic pharmacological properties. Watermelon also contains cucurbitacin E, which is considered an anti-inflammatory phytonutrient.

Polyphenols and Flavonoids

Watermelon contains phytochemicals such as polyphenols, flavonoids, stilbenes/lignans, and is a rich source of carotenoids and lycopene. Metabolic profiling studies have demonstrated that apigenin 6-C-glucoside, luteolin 6-C-glucoside, chrysoeriol C-hexoside, naringenin C-hexoside, and sucrose are among the main divergent metabolites distinguishing wild from cultivated watermelons.

Vitamins and Minerals

Watermelon is a major source of vitamin C and vitamin A. Vitamin B6 helps the body break down protein and supports immune and nerve function; vitamin C helps strengthen the immune system and aids in absorption of iron; and potassium is helpful in lowering blood pressure and is important for nerve function. The nutritional composition of watermelon includes carbohydrates, sugars, soluble and insoluble fibres, and good amounts of potassium and magnesium.

Water Content

Watermelon is 92 percent water and was first used by ancients as a source of water.

4. Mechanisms of Action

The L-Citrulline → L-Arginine → Nitric Oxide Pathway

The amino acid L-arginine is crucial for nitric oxide (NO) synthesis, an important molecule regulating vascular tone. Supplementation with precursors of NO synthesis is warranted because vascular dysfunction precedes cardiovascular disease. L-citrulline supplementation is recommended instead of L-arginine because most L-arginine is catabolized during its course to the endothelium. Given that L-citrulline, found mainly in watermelon, can be converted to L-arginine, watermelon supplementation appears to be effective in increasing plasma L-arginine and improving vascular function.

Nitric oxide is a gaseous molecule endogenously produced by endothelial cells that regulates vascular tone after crossing through the endothelium and diffusing to smooth blood vessel muscle cells. Reduced nitric oxide bioavailability contributes to the development of hypertension, atherosclerosis, worsening endothelial function, arterial stiffness, and ineffective stimulation of smooth muscle relaxation.

L-citrulline is not cleared from portal circulation and is converted to L-arginine in the kidney, where it is then circulated to other organs in the body. Thus, significant attention has been given to the use of L-citrulline as an effective agent for arginine supplementation.

Antioxidant Mechanisms

In vitro and in vivo, lycopene has been demonstrated to mitigate oxidative stress-induced metabolic dysfunctions and diseases including inflammation, obesity, and diabetes mellitus. Both the lycopene and secondary antioxidants present in watermelon have successfully inhibited oxidative DNA damage and modulated inflammatory pathways that precede carcinogenesis. In vitro, lycopene induces apoptosis and cell cycle arrest in prostate carcinoma cells, thereby providing a plausible molecular basis for cancer-preventive associations.

5. Scientific Evidence by Health Area

5.1 Cardiovascular Health and Blood Pressure

Overview: Several studies have demonstrated that watermelon (Citrullus lanatus) ingestion can increase nitric oxide bioavailability, an important vasoactive molecule that plays a critical role in the maintenance of vascular health. Watermelon is an L-citrulline-rich source, and its ingestion can increase plasma levels of L-citrulline and L-arginine, an essential substrate for NO synthesis. Thus, watermelon ingestion has been widely encouraged to improve vascular health in clinical populations.

Clinical trial evidence — blood pressure reduction: A series of RCTs conducted primarily by Arturo Figueroa's group at Florida State University has documented blood pressure effects in hypertensive adults. One study shows that watermelon extract supplementation reduces ankle blood pressure, brachial blood pressure, and carotid wave reflection in obese middle-aged adults with prehypertension or stage 1 hypertension. Another study found that watermelon supplementation reduced aortic blood pressure and myocardial oxygen demand during the cold pressor test and reduced the magnitude of cold-induced increases in wave reflection in obese adults with hypertension.

Figueroa et al. investigated the effect of watermelon extract (4 g of L-citrulline) for 6 weeks on aortic hemodynamic responses to the cold pressor test in middle-aged adults with hypertension. Watermelon supplementation was found to lower the magnitude of the augmented pressure response.

One trial showed that supplementation with 6 g/day of watermelon extract promoted a significant reduction in systolic (from 137.8 ± 3.9 to 126.0 ± 4.0 mmHg, p < 0.0001) and diastolic (from 79.2 ± 2.2 to 72.3 ± 2.0 mmHg, p < 0.001) blood pressure in prehypertensive and hypertensive individuals, though the final values in the treated group were not different from those in the placebo group.

Meta-analyses: A systematic review and meta-analysis found evidence that dietary supplementation with watermelon can be an effective nutritional intervention for reducing both systolic and diastolic blood pressure, with findings showing a reduction of 10.55 mmHg in systolic and 5.22 mmHg in diastolic blood pressure compared to control. Sensitivity analysis showed that DBP results can be influenced by some studies, but no obvious publication bias was found.

A further meta-analysis examining the effects of watermelon supplementation on cardiovascular disease risk factors, which included 9 RCTs, found that watermelon consumption significantly decreased systolic blood pressure, total cholesterol, and LDL.

Across these studies, reductions of 11.8–15.0 mmHg for systolic and 6.0–7.0 mmHg for diastolic blood pressure have been consistently reported.

Limitations: Some RCTs have found that watermelon consumption can decrease blood pressure, but others have not reported any beneficial effects. These inconsistencies may be due to interindividual variability in the response to watermelon consumption. All of the earlier confirmatory studies were from the same research group, in which the authors reproduced the methodological procedures across different populations. There are divergent findings when investigating the effect of watermelon supplementation on vascular function, which may be explained by the L-citrulline dose in watermelon products. In some instances, offering a sufficient amount of L-citrulline can be impaired by the greater volume (>700 mL) of watermelon needed to reach a proper dose.

5.2 Exercise Performance and Muscle Recovery

Overview: There is clear evidence that acute L-citrulline ingestion increases plasma L-arginine, the substrate for endothelial nitric oxide synthesis. However, the subsequent acute improvement in nitric oxide production and mediated vasodilation is inconsistent, which likely explains the inability of acute L-citrulline or watermelon to improve exercise tolerance. Chronic L-citrulline supplementation has been shown to increase nitric oxide synthesis, decrease blood pressure, and may increase peripheral blood flow, with these changes paralleled by improvements in skeletal muscle oxygenation and performance during endurance exercise.

Muscle soreness (DOMS): Studies have found that drinking watermelon juice, which contains L-citrulline, can lessen muscle soreness 24 to 72 hours post-exercise. It also helps the heart return to its normal rate more quickly after physical activity.

A comparative study in 33 participants examined the effects of pure L-citrulline (1.2 g) and 750 mL of watermelon juice versus mineral water as a placebo administered 2 hours before exercise using a multiple-sprint protocol with a deceleration phase to induce DOMS. There was a significant decrease of DOMS 12 h and 24 h post-exercise with both watermelon juice and pure L-citrulline (p=0.001).

A 2025 randomised controlled trial in non-athlete men: This open-labelled RCT was conducted on 42 non-athlete men for 8 weeks. Participants were randomised into two equal groups: the intervention group received 710 mL of watermelon juice (delivering approximately 1.65 g of L-citrulline per serving), and the control group received a calorie-matched placebo 1 hour before exercise. Both groups performed endurance exercise 3 days per week. At the end of the first week, exercise performance was evaluated, and participants were asked to complete the muscle soreness chart immediately and 24 hours after exercise.

Tarazona-Díaz et al. showed that acute watermelon juice (1.2 g of L-citrulline) or enriched watermelon juice (6 g L-citrulline) supplementation reduced muscle soreness but did not improve performance in untrained individuals. Gonzalez et al. indicated that short-term watermelon supplementation did not enhance exercise performance or muscle oxygenation parameters in resistance-trained men.

Limitations: Evidence for watermelon juice specifically improving exercise performance (as distinct from reducing muscle soreness) remains mixed and preliminary. Most studies are small, short in duration, and focused on particular populations. L-citrulline supplementation, but not acute ingestion, has been shown to improve exercise performance in young healthy adults.

5.3 Antioxidant Activity and Inflammation

Lycopene found in watermelon may reduce inflammation and oxidative stress, an imbalance between free radicals and the body's ability to fight their effects. A specific combination of antioxidants, lycopene and vitamin C, found in watermelon can lower inflammation and oxidative damage over time.

Lycopene has been shown to alleviate metabolic diseases that affect the bone, eye, kidney, liver, lungs, heart, and nervous system. These findings are largely from in vitro and animal models, with human evidence predominantly from dietary pattern and epidemiological studies rather than controlled trials with watermelon specifically.

5.4 Lycopene Bioavailability and Cancer Risk

Assessment of bioavailability of lycopene from foods was historically limited to tomato products. A 19-week crossover study examined the bioavailability of lycopene from fresh-frozen watermelon juice. Healthy, nonsmoking adults (36–69 years) completed three 3-week treatment periods, each with a controlled, weight-maintenance diet. This study confirmed that lycopene from watermelon is bioavailable in humans.

Epidemiological and mechanistic data suggest that lycopene reduces the risk of prostate and other cancers. In vitro, lycopene induces apoptosis and cell cycle arrest in prostate carcinoma cells, thereby providing a plausible molecular basis for these associations. However, it should be noted that human interventional evidence specific to watermelon consumption and cancer outcomes is lacking; the available data are largely epidemiological or derived from in vitro and animal studies.

5.5 Dietary Quality and Metabolic Health

One study examined data from the National Health and Nutrition Examination Survey (NHANES) to compare the diets of watermelon eaters and non-consumers. The analysis found that both children and adults who consumed watermelon generally had higher-quality diets overall. Watermelon consumers took in more dietary fibre, magnesium, potassium, vitamin C, vitamin A, lycopene, and other carotenoids. At the same time, they consumed lower amounts of added sugars and saturated fat. The study was originally published in Nutrients in 2022. This is an observational finding and does not establish causality.

5.6 Endothelial Function

One trial investigated the consumption of separate parts of watermelon rind (containing 387.4 mg of L-citrulline and 75.3 mg of L-arginine), flesh (containing 471.5 mg of L-citrulline and 175.2 mg of L-arginine), and seeds (containing 231.3 mg of L-citrulline and 69.3 mg of L-arginine) on the endothelial function of overweight/obese subjects. Following all supplementations, both plasma L-citrulline and L-arginine increased significantly (p < 0.05), but no effects on brachial artery flow-mediated dilation (FMD) were observed. This suggests that while watermelon elevates amino acid precursors, translation to measurable endothelial function improvement is not guaranteed.

5.7 Male Reproductive Health

Lycopene, a carotenoid responsible for the red pigmentation of watermelon, has aroused growing interest as a natural antioxidant agent in the context of male reproductive health. Lycopene has proven to be able to specifically reduce oxidative damage in sperm, which is associated with infertility in men. Moslemi et al. found that daily lycopene supplementation for a period up to 12 months improved parameters such as sperm concentration and even outcomes such as pregnancy. These findings relate to supplemental lycopene in general and are not specific to watermelon as a food source.

6. Dosage Forms and Reported Dosages

Dosages used in clinical research have varied considerably. The following reflect amounts as reported in peer-reviewed sources:

• Watermelon extract (powder): Previous clinical studies have demonstrated blood pressure-lowering effects of watermelon supplementation enriched with L-citrulline and L-arginine (typically 4–6 g in a 2:1 ratio) in pre-hypertensive and hypertensive individuals.
• Watermelon extract — specific trial dose: Figueroa et al. used watermelon extract delivering 4 g of L-citrulline over 6 weeks to assess aortic hemodynamic responses.
• Watermelon extract — 6 g/day dose: Supplementation with 6 g/day of watermelon extract was used in a trial examining blood pressure in prehypertensive and hypertensive individuals.
• Watermelon juice — exercise trials: In a 2025 RCT of 42 non-athlete men, the intervention group received 710 mL of watermelon juice 1 hour before exercise. This delivered approximately 1.65 g of L-citrulline per serving.
• Watermelon juice — DOMS study: In a comparative trial, 750 mL of watermelon juice was administered 2 hours before exercise.
• Enriched watermelon juice (sports context): Tarazona-Díaz et al. used enriched watermelon juice containing 6 g L-citrulline to examine effects on muscle soreness.
• Citrulline content of standard servings: Watermelon contains L-citrulline ranging from 1.0–3.5 mg/g fresh weight in the flesh. In one study, an 8 oz (240 mL) sample of blenderised watermelon contained approximately 225–689 mg of L-citrulline.

In some instances, offering a sufficient amount of L-citrulline can be impaired by the greater volume (>700 mL) of watermelon needed to reach a proper dose of L-citrulline. While watermelon alone offers natural benefits, the quantity of L-citrulline in typical servings is considerably lower than therapeutic doses used in athletic or cardiovascular studies.

7. Body Systems and Health Areas Associated with Watermelon

• Cardiovascular system: Blood pressure regulation, arterial stiffness, aortic haemodynamics, endothelial function, wave reflection amplitude via citrulline → arginine → NO pathway.
• Musculoskeletal system: Reduction of delayed-onset muscle soreness (DOMS), potential support for post-exercise recovery.
• Antioxidant/anti-inflammatory systems: Lycopene-mediated reduction of oxidative stress and modulation of inflammatory markers.
• Oncological considerations: Lycopene has epidemiological and mechanistic associations with reduced prostate cancer risk; evidence is preliminary and not specific to watermelon whole food.
• Male reproductive health: Lycopene's antioxidant effects on sperm quality.
• Hydration and renal: High water content (~92%) supports hydration; however, the fruit's high potassium content requires caution in patients with impaired renal potassium excretion.
• Metabolic health: Associated with higher-quality dietary patterns and lower intake of added sugars and saturated fat in NHANES observational data.

8. Safety Considerations and Interactions

General Tolerability

Simply consuming L-arginine as a dietary supplement is not an option for many hypertensive adults because it can cause nausea, gastrointestinal tract discomfort, and diarrhoea. In contrast, watermelon is well tolerated; participants in the Florida State pilot study reported no adverse effects.

Hyperkalemia in Patients with Kidney Disease

The most clinically significant documented safety issue is watermelon-induced hyperkalemia in individuals with chronic kidney disease (CKD). In patients with stable chronic kidney disease on renin–angiotensin–aldosterone system (RAAS) inhibitors, an exogenous source of increased potassium intake should be investigated in patients with new hyperkalemia. Watermelon is an under-recognised source of excess dietary potassium, with 2 wedges (one-eighth of a watermelon) containing 16.4 mmol (640 mg) of potassium. This emphasises the importance of dietary counselling in patients with advanced CKD, including end-stage renal disease. A case series of 3 patients with excess watermelon consumption causing severe hyperkalemia has been published.

In the cases presented, three patients with some form of CKD developed hyperkalemia after eating large amounts of watermelon over a period ranging from three weeks to two months. Doctors diagnosed hyperkalemia caused by increased dietary potassium intake in combination with severe CKD and blood pressure medication (lisinopril). After being advised to reduce watermelon intake, the hyperkalemia did not recur.

Stages III–V CKD, diabetes mellitus, congestive heart failure, and certain medications—particularly renin–angiotensin–aldosterone system inhibitors and mineralocorticoid receptor antagonists—are the leading risk factors for hyperkalemia.

Research indicates that in people without kidney disease, the body adapts and excretes excess potassium through urine. Nevertheless, people with heart failure, kidney disease, type 1 diabetes, adrenal insufficiency, and liver disease may have difficulty managing excess potassium.

Wild-Type and Cucurbitacin Toxicity

Wild relatives such as Citrullus amarus may have bitter, inedible fruits due to high levels of cucurbitacins, which can be mildly toxic if consumed in large quantities. Cultivated watermelons are safe for human consumption.

Drug Interactions

The primary interaction concern involves watermelon's potassium content and its additive effect with potassium-sparing medications. Medications that can cause or worsen hyperkalemia include RAAS inhibitors, mineralocorticoid receptor antagonists, nonsteroidal anti-inflammatory drugs (NSAIDs), calcineurin inhibitors, heparin and its derivatives, and trimethoprim. High watermelon intake in patients on any of these agents who also have impaired renal function should be evaluated carefully.

Lycopene Safety

Lycopene's protective effects against toxins, safety in its use, and possible toxicity have been explored in the literature. At levels consumed from whole foods, lycopene from watermelon has not been associated with adverse events in clinical studies reviewed. Very high-dose supplemental lycopene (isolated, not from watermelon) studies have occasionally reported gastrointestinal symptoms and "lycopenodermia" (skin discoloration), but these are not relevant to normal dietary watermelon consumption.

References

• Shulaev V et al. "A Catalog of Natural Products Occurring in Watermelon—Citrullus lanatus." Frontiers in Plant Science (2021). PMC8476801.
• dos Santos Baião D et al. "Watermelon Nutritional Composition with a Focus on L-Citrulline and Its Cardioprotective Health Effects—A Narrative Review." Nutrients (2025). PMC12566930.
• Volino-Souza M et al. "Current Evidence of Watermelon (Citrullus lanatus) Ingestion on Vascular Health: A Food Science and Technology Perspective." Nutrients (2022). PMC9318495.
• Figueroa A, Wong A, Jaime SJ, Gonzales JU. "Influence of L-citrulline and watermelon supplementation on vascular function and exercise performance." Curr Opin Clin Nutr Metab Care. 2017;20(1):92-98. PMID 27749691.
• Figueroa A et al. "Watermelon extract supplementation reduces ankle blood pressure and carotid augmentation index in obese adults with prehypertension or hypertension." Am J Hypertens. 2012;25(6):640-3. PMID 22402472.
• Figueroa A, Wong A, Kalfon R. "Effects of watermelon supplementation on aortic hemodynamic responses to the cold pressor test in obese hypertensive adults." Am J Hypertens. 2014. PMID 24572702.
• "The effect of watermelon supplementation on blood pressure: a meta-analysis of randomised clinical trials." ScienceDirect (2023).
• "Watermelon consumption decreases risk factors of cardiovascular diseases: A systematic review and meta-analysis of randomized controlled trials." Diabetes Research and Clinical Practice (2023).
• "Watermelon extract reduces blood pressure but does not change sympathovagal balance in prehypertensive and hypertensive subjects." Blood Pressure (2016).
• Norouzzadeh M et al. "The Effects of Watermelon Juice on Muscle Hypertrophy, Exercise Performance, and Muscle Soreness in Non-Athlete Men Undergoing Endurance Training: A Randomized Controlled Trial." Food Science & Nutrition. 2025. PMC12515702.
• "Effect of citrulline on post-exercise rating of perceived exertion, muscle soreness, and blood lactate levels: A systematic review and meta-analysis." PMC7749242.
• "Consumption of Watermelon Juice Increases Plasma Concentrations of Lycopene and β-Carotene in Humans." Journal of Nutrition (2003). ScienceDirect.
• "Lycopene: A Potent Antioxidant with Multiple Health Benefits." PMC11179732 (2024).
• "Association of Lycopene and Male Reproductive Health: Systematic Review and Meta-Analysis." PMC12346668 (2024).
• "Watermelon-Induced Hyperkalemia: A Case Series." Annals of Internal Medicine: Clinical Cases (2023).
• "Dose–Response Effect of Watermelon Consumption on Ambulatory Blood Pressure in Adults with Elevated Blood Pressure: A Randomized Controlled Pilot Trial." PMC12525780 (2025).
• University of Missouri Extension. "Watermelon: A Brief History." Integrated Pest Management, 2020.
• McClung Museum of Natural History & Culture, University of Tennessee. "Plant of the Month: Watermelon." 2021.
• National Geographic. "The 5,000-Year Secret History of the Watermelon." 2015.
• "Comparative Metabolomic Profiling of Citrullus spp. Fruits Provides Evidence for Metabolomic Divergence during Domestication." PMC7911689 (2021).
• Rimando AM, Perkins-Veazie PM. "Determination of citrulline in watermelon rind." J Chromatogr A. 2005.
• "Development of Isocratic RP-HPLC Method for Separation and Quantification of L-Citrulline and L-Arginine in Watermelons." PMC5954852 (2018).
• MDPI Nutrients. "Watermelon Nutritional Composition with a Focus on L-Citrulline and Its Cardioprotective Health Effects—A Narrative Review." 2025.