Six different brands of energy drinks (EDs) were analyzed to determine the concentration of caffeine in accordance with the information on the package label. Approximately 28.1 milligrams per 100 milliliters (mg/100 ml) of caffeine was present in the Mo energy drink brand, which was nearly 1.5 times the caffeine concentration listed on the product label. The energy drink with the highest caffeine content was Dragon, which contained 30.1 mg/100 ml, or a total of 150.5 mg per 500 ml bottle. Manufacturers of energy drinks (EDs) should accurately list the amount of caffeine and other ingredients on the product label so that consumers know how much of each ingredient they are taking. Taking too much caffeine can be bad for your health.

1. Introduction

Energy drinks (EDs) are nonalcoholic, sugary beverages that contain variable amounts of caffeine, taurine (amino acid), glucuronolactone, herbal extracts, minerals, and vitamins in order to increase physical and mental endurance [1]. The majority of people who consume EDs are engaged in strenuous physical activity, as well as those who prefer to remain alert for longer durations, such as athletes, drivers, and students. Because EDs are marketed for their perceived or actual benefits as stimulants, performance enhancers, and energy boosters, this is the case [2]. EDs were first introduced in Asia and Europe around 1960 [1]. In 1987, when the most well-known brand, Red Bull, was introduced, its consumption became very popular [3].

Due to the widespread and long-term consumption of beverages containing caffeine naturally, such as coffee and tea, the regulation of beverages containing added caffeine has been complicated [4]. Nevertheless, a number of nations have enacted regulations governing the labeling, distribution, and sale of energy drinks containing significant amounts of caffeine [4]. The European Food Safety Authority mandates that energy drinks with a caffeine content greater than 150 parts per million (ppm) or 150 mg per liter must be labeled as having “high caffeine content” and the exact amount must be specified [5]. Australia has banned energy drinks with more than 320 ppm of caffeine and wants to put them in the same category as drugs. Countries such as Denmark, Uruguay, and Turkey have banned energy drinks entirely, and Sweden has prohibited the sale of energy drinks to minors [5]. The maximum recommended daily caffeine intake varies between 2.5 mg/kg/day and 6 mg/kg/day for children, 100 mg/day for adolescents, and 400 mg/day for adults [6]. Tolerance to caffeine varies between individuals, with the majority of people developing toxic symptoms at doses of 200 mg [7].

A study conducted by CSE [4] to determine the caffeine content of energy drinks revealed deviations from the amount of caffeine listed on the label, as shown in (Table 1).

Joo et al.found that the health risks associated with ED consumption are primarily attributable to their caffeine content. An overdose of caffeine can cause palpitations, hypertension, dieresis, stimulation of the central nervous system, nausea, vomiting, marked hypocalcemia, metabolic acidosis, convulsions, and, in rare cases, death [9]. There is also an increased risk of arterial hypertension and Type 2 diabetes in adults due to the fact that high caffeine consumption reduces insulin sensitivity [10]. Caffeine consumption increases the risk of late miscarriages, small-for-gestational-age infants, and stillbirths among pregnant women. Frequent caffeine consumption may impair cognition in general and long-term memory and learning in particular [11]. Caffeine at a dose of 400 mg increases anxiety, particularly when combined with a stressful task. Some studies suggest that EDs can trigger the onset of the first seizure and contribute to stroke [12].

Caffeine overconsumption is linked to a variety of additional health issues. Caffeine overdose, for instance, has been reported as a potential cause of rhabdomyolysis [13]. Due to their diuretic effect, EDs can cause hypokalemia as well as high creatinine kinase levels and renal impairment [14]. Individuals who do not regularly consume large quantities of caffeine may experience an increase in diuresis after consuming EDs. Therefore, dinks have an overall dehydrating effect [15]. In addition, Hasselkvist et al. [16] found a significant relationship between EDs and dental erosion. The low pH of energy drinks is largely responsible for their high demineralization potential [17]. According to Vos and Lavine [18]; increased consumption of sugar-sweetened beverages, including ED, is associated with overweight and obesity, as well as an increased risk of diabetes mellitus and cardiometabolic diseases because beta cells are unable to secrete enough insulin to maintain normal blood glucose levels when exposed to excesses of simple sugars for extended periods of time.

Caffeine, the primary component of the drinks, stimulates sympathetic nerves, which can cause adverse health effects, such as sudden death .

Despite an increase in the number of industries in Tanzania producing various brands of EDs and the presence of imported products, there are no published studies in Tanzania assessing the concentration of caffeine in ED products in accordance with the information on the package label. The study’s overarching objective is to determine the amount of caffeine used in energy drink products in accordance with the labeling information.

2. Materials and Procedures

2.1. Estimation of Sample Size for Energy Drinks

Purposeful sampling was used to collect twelve energy drink samples, two from each of six brands sold in Tanzanian grocery stores and convenience stores. Two grocery stores were visited and the shopkeepers were asked to select six samples of EDs beverages that were most likely preferred by customers. The other three must consist of brands produced in Tanzania, and the other three must consist of brands imported from outside the country; this was done in both grocery stores.

2.2. Data Collection

The samples were randomly obtained by visiting two grocery stores and asking the shopkeepers to select six samples of EDs beverages that were most likely preferred by customers. Three of the samples had to be Tanzanian brands, and the other three had to be foreign brands; this was done in both grocery stores. The samples were placed in a cool box with icepacks and transported within one to two hours to the Food Science and Technology Laboratory at Sokoine University of Agriculture (approximately 2.5 km from the sample collection sites), where they were stored at a temperature of 1.6°C until analysis.

2.3. Procedures for Caffeine Extraction and Sample Measurements

Each working standard and sample solution yielded 1.0 mL of homogenized beverage. This sample was placed in a separating funnel, 1 ml of 20% (w/v) methanol and 5 ml of chloroform were added, and the mixture was shaken for five minutes. The absorbance of the lower (organic) layer containing caffeine was measured at 274 nm using a UV Vis spectrophotometer (X-ma 3000, England). The extraction method was performed twice for each sample (Table 2).

A 1000 ppm standard stock solution was prepared by dissolving 0.1 g of pure caffeine in 100 ml of chloroform. We prepared serial dilutions of 1 to 25 ppm, measured absorbance, determined a linear regression equation, and used Microsoft Excel to tabulate measurement data and conduct a linear regression analysis. This allowed for the calculation of a concentration factor, which was then used to quantify the caffeine. The final caffeine content of the tested beverage was then calculated using the concentration of the extracted sample solution and the following equation (Figure 1):

3. Results

3.1. Analyses of the Actual Amounts of Caffeine Found in Energy Drink Ingredients

The six different brands of ED beverages in duplicates (a total of 12) consisted of three brands that were produced in Tanzania (Azam energy drink, Mo energy drink, and Power energy drink) and three that were imported from abroad (Kungfu energy drink, Dragon energy drink, and Monster energy drink). Of the six samples tested, the sample of Dragon energy drink had the highest caffeine content at 30.1 mg/100 ml, resulting in a total of 150.5 mg of caffeine per bottle (Table 3).

Caffeine content samples (BEVERAGES) analyzed in duplicate (S1 and S2) during a 2018-2019 study of energy drink consumption rate, knowledge, and perceived side effects among long-distance car drivers in Morogoro municipality, Morogoro, Tanzania (Table 3).

Monster energy drink had the highest caffeine content per serving (per packaged bottle), followed by Dragon energy drink and Kungfu energy drink, followed by Power energy drink and Azam energy drink, with Mo energy drink having the least amount of caffeine indicated on its package label (Tables 4 and 5).

4. Discussion

Since caffeine is the main ingredient in energy drinks, caffeine overdoses are the leading cause of adverse health effects [19]. Due to its higher caffeine content, some nations, including Turkey, have banned its consumption [20]. Referring to the current FDA regulation, “dietary ingredients that are specifically added to products must contain 100 percent of the volume or weight declared on the label (with the exception of an analytical method-attributable deviation), and whereas naturally occurring dietary ingredients must be present at 80 percent of the declared value” [21, 22]. In our study, we compared the caffeine concentrations of six EDs samples (Azam, Dragon, Kungfu, Mo, Monster, and Power) with the caffeine content listed on the product’s label. Five of the examined EDs contained less caffeine than indicated on the product label. However, the Mo energy drink contained approximately 1.60 times the amount of caffeine as indicated on the product label. This study’s findings are comparable in some ways to those reported by Consumer Reports [23]; which examined the caffeine content of 16 energy drinks and found that 10 of the samples had values within 20% of the actual numbers listed on the label, while 5 of the product samples had caffeine amounts greater than 20% above what was indicated on the label, and 1 product had caffeine amounts 70% below what was indicated on the label. Similar research [24] revealed that the majority (89%) of the EDs samples they analyzed contained caffeine within 20% of the labeled amounts. A study [20] found that 100 ml of EDs contains between 80 and 242 mg of caffeine, which is equivalent to consuming eight cups of strong coffee per day, thereby increasing the risk of toxicity and disrupting the overall health structure.

5. Conclusion

Manufacturers should accurately label the caffeine concentration on their energy drink products, and consumers are advised to use the recommended amount of caffeine in order to avoid adverse health effects that may result from excessive consumption. Additionally, consumers should avoid energy drink products that do not adhere to the caffeine concentration indicated on the package label.

5.1. Recommendations

The government and responsible agencies should take the necessary steps to ensure that all energy drinks sold in the United States contain the recommended amount of caffeine, which will be specified on the packaging label, in order to reduce the risk of caffeine-related side effects.

Data Availability

All data generated or analyzed during this study are included in this published article.

Conflicts of Interest

There are no conflicts of interest declared by the authors.


I am grateful to the management of the Department of Food Science and Technology (SUA) for granting me permission to analyze my research samples in their laboratory. Research funds were kindly offered by authors’ supervisor, Prof. Helen Ngowi.