Effect of Watermelon (Citrullus Lanatus) Extracts on Testosterone Levels a Systematic Review and Meta- Analysis

Research Article

Austin J Nutri Food Sci. 2019; 7(6): 1127.

Effect of Watermelon (Citrullus Lanatus) Extracts on Testosterone Levels a Systematic Review and Meta- Analysis

Salvador IC* and Marin V

School of Nutrition, UNIRIO, Federal University of Rio de Janeiro, Brazil

*Corresponding author: Salvador IC, School of Nutrition, UNIRIO, Federal University of Rio de Janeiro, Brazil

Received: July 16, 2019; Accepted: September 10, 2019; Published: September 17, 2019


Testosterone levels have been declining 1% every year in the world. Natural alternatives have recently been sought through plants, teas and natural extracts that may aid in pharmacological treatments that usually have several adverse symptoms. One fruit that has aroused interest in this area is the watermelon (Citrullus lanatus), which appears to promote increased testosterone levels. This study was carried out by searching the main databases available through the keywords “Citrullus lanatus” and “testosterone”. After the exclusion of articles that did not meet the inclusion criteria, 6 articles were analyzed. Of these, all presented higher levels of serum testosterone after the period of treatment with alcoholic extract of different parts of the fruit. The concentration predominantly used in the studies was 200 mg/kg, and although the effect is dose dependent, at 30 mg/kg of body weight there already appears to be an effect. The letal dose of consumption of the extracts was found at concentrations higher than 2 g/kg. More studies should be done using forms of non-alcoholic extraction. Since all studies were performed on animals, supplementation in humans is necessary to evaluate the applicability of this substances, and the effects on human physiology.

Keywords: Citrullus lanatus; Testosterone; Meta-analysis


On the meeting about the ambient challenges of the reproductive health in 2007, it was reported a global decrease in the testosterone levels of 1% each year during the last 50 years, leading to a worsening in the global male health and high rates of infertility. Currently one in each 6 men could be considered infertile, these scenario is more common in the urban area [1]. Testosterone is formed in the Leydig cells at the testicles, rates of normality for a healthy men ranges between 300 and 900 ng/dL. Testosterone finds receptors in practically all tissues, and promotes diverse effects in the development of the masculine sexual characters, among which, one of most important consists of the development of muscle and strength. Due to this effect, frequently, this hormone or its synthetic analogues are used by athletes to improve its muscular performance [2]. The consumption of synthetic anabolic steroids is related to a series of adverse effects to its chronic use, among which cardiovascular alterations (arrhythmia, dislipidemia, thrombosis, hypertension and myocardium hypertrophy leading to ventricular insufficiency), psychological alterations (impulsive and aggressive behavior, anxiety, sleeplessness and eventually personality disorders), testicular atrophy, hepatic peliosis, acne, folliculitis and renal injury [3]. Therefore, it comes of great importance the study of natural plants and extracts that are capable to increase testosterone levels without presenting deleterious effects.

The watermelon (Citrullus lanatus) is a tropical fruit from a ground plant of same name from the Curcubitaceae family [4]. It presents great economic importance, being produced in the whole world and is very appreciated by its nutritional value, refreshment and low caloric value [5]. The interior part of the watermelon is generally colored and presents great amounts of beta carotene and lycopene which possesses recognized antioxidantt activity. Its extracts are used for diverse purposes as antihypertensive, anti-inflammatory and antimicrobials [6]. Each part of the watermelon possesses distinct characteristics on its composition. The seeds for example are excellent protein sources, being able to be used in the feeding for preparations and alimentary plans [7]. The extracted oil of the seeds is composed mainly by linoleic acid, palmitic acid and estearic acid. It also contains phytochemicals as the lycopene, saponins, flavonoids alkalis, oxalate and tannin [8].

Materials and Methods

Researches were performed in the databases Scielo, Web of Science, Google scholar, OVID, PubMed, SCOPUS and BVS at July, 2019, through the key words “Citrullus lanatus” and “testosterone”. A total of 178 articles were found, of which 27 were selected through the title. At this point, all articles in english or portuguese were selected if the title showed some correlation with both keywords used. Of the selected articles, 1 could not be accessed for complete reading and was excluded. After the reading, 8 were excluded due to the experimental model that did not fit the election criteria, 3 didn’t present or didn’t control of the dosage of supplied C. lanatus, and 6 articles didn’t detailed the dosage of testosterone used. Other 3 articles were removed for repetition in the different databases. Figure 1 presents a summary of the research processes and selection. The inclusion criteria for the articles to our meta-analysis were: be written in English or portuguese; use only extracts of Citrullus lanatus at the treatment; specify the concentrations of the solutions used; specify the testosterone levels before and after treatment, or present a control group exposed to the same conditions as the treated group so the comparison between them were possible. Give the solution exclusively orally to the subjects. The risk of bias of the six studies included, were scored through QUADAS-2 questionaire and showed low risk of bias at all parameters (table not shown). The meta- analysis was analyzed using the software Review Manager 5.3 (2014).