Why Do Energy Drinks Make Me Tired?

The potential mind-boosting, body-moving powers of an energy beverage largely stem from its ingredients. While these drinks may vary based on taste, size, and calories, many contain similar ingredients. These ingredients include:[1]

• Caffeine
• Sugar
• Taurine
• Guarana

Although studies suggest that these ingredients can increase alertness and energy, they cause our bodies to crash even harder.[1]

Let’s explore each ingredient in depth, specifically focusing on how they can pick you up before you suffer a caffeine crash.

Caffeine

People worldwide have long praised caffeine consumption—and for good reason. In addition to helping you stay awake and alert, caffeine may help prevent certain diseases.[2] However, caffeine can also cause a crash after the initial energy boost wears off.

If you’re asking yourself, “why does caffeine make me sleepy,” you may find the answer in caffeine's pharmacological properties. The chemical promotes sleep in the following ways:[1]

By backing up adenosine receptors – Blocking the brain’s adenosine receptors is one way caffeine makes you feel energetic. These receptors help enable sleep by catching sleep-promoting neurotransmitters. However, even though your adenosine receptors are temporarily blocked, your neurotransmitters keep firing. This results in a buildup of neurotransmitters that hits your adenosine receptors once the caffeine wears off.

By functioning as a diuretic – As a diuretic, caffeine causes the body to expel more water than normal.[3] This can lead to dehydration. When you’re dehydrated, your blood tends to thicken, preventing the easy movement of vital nutrients and minerals. Without these nutrients and minerals, you may feel sluggish—especially as the day wears on.

In general, the more caffeine an energy drink contains, the steeper the dropoff in energy levels following the caffeine crash. Most energy drinks contain caffeine ranging from 70 to 200 milligrams per 16-ounce serving.[1]

Save up to 30% when you bundle! Create your bundle!

Sugar

From candy bars to sports beverages, dried fruits to energy drinks, sugar is found in many foods and drinks. In fact, sugar is so prominent in our diets that dieticians recommend people limit their sugar intake to no more than 150 calories a day.[4]

Because of this, it is important that you consider what food gives you energy while making sure it is still healthy for you. Sugar can be both beneficial and detrimental for your body. While sugar can boost energy levels, too much of it can also lead to a host of health consequences, including:[5]

• Obesity
• Diabetes
• Metabolic syndrome
• Some cancers
• Cardiovascular disease

Sugar can also cause you to feel like you’ve just run a marathon after the initial burst of energy wears off. Here’s how sugar can make you feel tired:[6]

Increased insulin production – When you eat a meal loaded with sugar, you get more than a burst of sweetness on your taste buds. You also get increased insulin production. In short, insulin is a hormone produced by the pancreas that absorbs the body’s excess sugars. This increase in insulin can make you feel tired.

Nutrient composition – As a simple carbohydrate, sugar provides the short-term energy benefits of carbohydrates. However, consuming excessive carbohydrates—especially simple carbohydrates—can lead to fatigue. That’s because the body easily metabolizes carbohydrates, leading to an energy deficiency after all the carbs have been processed.

Like caffeine, sugar is a prominent ingredient in many energy drinks. Most energy drinks contain between 50 and 62 grams of sugar per 16-ounce serving.[1]

Taurine

Taurine is a vital amino acid that supports brain and heart functions. Taurine can help the body function in the following ways:[1]

• May improve retinal function
• Can improve bile acid conjugation
• May lessen exercise-induced DNA damage

When paired with caffeine, taurine has been shown to help improve mental acuity.[7] However, other studies show that taurine can increase lethargy.[8] That’s because taurine can interact with the sleep-promoting GABA receptor.[8]

What’s surprising is that energy drinks include taurine, despite it negatively interacting with caffeine, and ultimately slowing us down. Most energy drinks contain 2,000 milligrams of taurine per 16-ounce serving.[1]

Guarana

A plant native to Amazonian rainforests, guarana contains high levels of caffeine. In fact, with caffeine levels ranging from two percent to eight percent, guarana contains the most caffeine of any plant. This makes guarana a popular additive in any energy beverage.[9]

However, while guarana can boost energy levels in the short term, its high caffeine content can lead to tiredness. This is primarily due to adenosine receptor backup.[9]

Furthermore, guarana can cause tiredness in the following ways:[9]

The plant can inhibit hunger – Given guarana’s high caffeine content, the plant has been shown to inhibit feelings of hunger. As a result, people are less likely to eat while consuming drinks containing guarana. This can lead to nutrient deficiency, low blood sugar, and increased fatigue.

The plant contains theobromine and theophylline – Like caffeine, the stimulants theobromine and theophylline can increase energy. However, by causing a neurotransmitter buildup, they can also promote sleepiness.

The amount of guarana in most energy drinks is unknown. That’s because many energy drinks do not list the exact amount of guarana in each drink. When they do, guarana extract levels tend to hover around 50 milligrams per 16-ounce serving.[1]