John Mgirane works long hours. During the day, he works as customer care at a telecommunications company, and, at night, he helps out at his mother’s supermarket in Kimironko. The supermarket runs until midnight. It wears him out and to get that extra burst of energy, he relies on energy boosters, commonly known as energy drinks. He takes at least one each day and on bad days, two.An energy drink is a type of beverage containing stimulant drugs, chiefly caffeine, which is marketed as providing mental or physical stimulation. The boosters are preferred by people seeking extra energy kick or endurance. Although ingredients may differ from brand to brand, the most common are caffeine, sugar (artificial sweeteners) and herbal extracts such as guarana.  Caffeine is a renowned stimulant also found in coffee and tea. Caffeine, whether it is in coffee or tea or a soft drink, moves easily from the intestines into the bloodstream, and from there to organs, and before long has penetrated almost every cell of the body. This is why caffeine is such a celebrated stimulant. Most substances cannot cross the blood-brain barrier, which is the body’s defensive mechanism. Caffeine does so easily. Within an hour or so, it reaches its peak concentration in the brain, and there it does a number of things amongst them blocking  the action of adenosine, the  brain chemical that’s responsible for making  you sleepy, lowering your blood pressure  and slowing down your heartbeat. Then, as quickly as it builds up in your brain and tissues, the caffeine is gone—which is why it’s so safe. Caffeine in ordinary quantities has never been conclusively linked to serious illness but in energy drinks the amounts could excessive.Some users may argue that the drink’s ingredients (caffeine and sugar) can be found in other beverages that are considered ‘safe’ such as tea and coffee but the amount varies; some energy drinks have an equivalent of caffeine in seven coffee cups. Energy drinks also contain high amounts of sugar in form of glucose which can be readily absorbed into the body system. These sugars contain calories.Although the manufacturers claim that energy drinks can improve your endurance and performance, many health experts disagree. Any boost you get from drinking them, they say, is solely from the sugar and caffeine.The most common brands of energy drinks in Rwanda are Red Bull, Horse Power and Shark. They retail at between Rwf1,000 and Rwf2,000 at most supermarkets and shops.Spelling dangerMost users of energy drinks rely on them to stay revitalised during or after long working hours. Mgirane, for instance, says energy boosters help him get through long days and give much needed energy. "The best thing about energy boosters is that they are instant. They are convenient, you don’t have to prepare anything, you open a can and in a few minutes you are revitalised, it is almost medicinal,” Mgirane says.  Dr Joseph Nkurunziza, a general physician at Rwanda Military Hospital, Kanombe, says energy drinks’ agility in response is one of its benefits and vices. However, the latter outweighs the former, experts say."Energy boosters go against the normal physiological digestion order of the human body. The fact that they do not need as much processing as other foods consumed make them convenient and at the same time, the large amounts of calories they deposit into the body could overwhelm the metabolism process, leaving excessive deposits of calories in the body.  This could easily result to obesity; that’s why you find some people watch their diets but end up being overweight,” Dr Nkurunziza says.Rene Kabaro, a nutritionist in Kigali, discourages the use of energy drinks, saying they have no nutritional value."The sugars and herbs used in energy drinks are mostly artificial and the excessive caffeine contents are not recommended,” Kabaro says.Energy drinks are often used as mixers when making various alcoholic cocktails to tame the effect of alcohol. However, Mayo Clinic says mixing energy drinks with alcohol may be even more problematic. Energy drinks can blunt the feeling of intoxication, which may lead to heavier drinking."Fatigue is the body’s way of saying it’s had enough to drink and it’s dangerous to continue to try to fool your body. Mixing alcohol and energy drinks does not lessen the alcoholic content in a drink. It will still take the liver the same amount of time to process the alcohol,” Dr Nkurunziza says. "Actually one is at risk of overwhelming the liver since it has to process the energy booster and the alcohol. By mixing the two (a depressant and a stimulant) you’re sending mixed messages to your nervous system which can cause cardiac related problems, hallucinations and seizures.”Dr Nkurunziza says because of the high caffeine content in most energy drinks, they are highly addictive."After using them for a while, some users begin to rely on them heavily. It becomes almost like a prescription drug,” Dr Nkurunziza says.The addiction problem should be treated seriously like any other over-dependence. One should seek help from psychosocial support and help from counselors to kick the addiction. It is not possible to just wake upon day and resolve to quit being dependent on them.  Energy drinks have also been known to cause cardiovascular complications and other heart related ailments. "Once consumed, they excite the heart; they increase the heart rate and the blood pressure. At times heart attacks could result from this. It is because of this reason that people with heart conditions or high blood pressure are advised to exercise caution when using the boosters. It is highly recommended that they consult their physicians for guidance,” Dr Nkurunziza says.The high amounts of sugars present in energy drinks could cause lifestyle illnesses such as diabetes, the doctor says. "High amounts of sugar can overwhelm a pancreas, an organ responsible for insulin production to process break down and absorb sugar, once it is overwhelmed, it easily gets worn out and that’s the onset of diabetes,” he says. The fact that energy boosters act as instant temporary fixes puts the user at risk of fatigue and exhaustion. The ingredients present in energy boosters cause temporary stimulation which causing to long term .Pregnant women risk miscarriages if they use energy boosters. "Pregnancy reduces a woman’s ability to process caffeine, instead of the three or four hours normally taken by, an expectant mother could take up to 10 hours. In between, there is a lot of irritability, rapid heart rate and high blood pressure, which may not go well with the foetus,”  Dr Nkurunziza.  Energy drinks cannot be labelled as ‘bad’ but they should not be overused or abused. We all have those days when we have deadlines to beat but we are exhausted, one is not prohibited, but habitual use has dire consequences.