What side effects does 5-Hour Energy have?

October 12, 2025 •

5 min read

With a standard shot containing 200–240 mg of caffeine—more than a large cup of coffee—concerns persist about what side effects does 5-Hour Energy have and if the stimulant-heavy blend is safe. This article explores both common and serious adverse reactions to help you make an informed decision about your nutrition and energy habits.

Quick Summary

This guide examines the potential health consequences of consuming 5-Hour Energy, detailing side effects related to high caffeine and vitamin intake. It addresses cardiovascular, digestive, and psychological impacts, potential risks for certain individuals, and the infamous 'caffeine crash' that can follow. Recommendations for healthier, natural energy alternatives are also provided.

Key Points

High Caffeine Content: A single shot contains 200–240 mg of caffeine, leading to potential side effects like jitters, anxiety, increased heart rate, and digestive issues.
Risk of Cardiac Events: Overconsumption, particularly in sensitive individuals or those with pre-existing heart conditions, can lead to serious adverse effects, including heart attacks and cardiac arrest.
Excessive Synthetic Vitamins: The high dosages of synthetic B-vitamins, especially Niacin and B6, can be toxic in excess and have been linked to liver damage and nerve issues.
Beware the Crash and Dependency: The stimulant effect is often followed by a significant crash, potentially creating a cycle of dependency and leading to adrenal burnout over time.
Inappropriate for Vulnerable Groups: Not recommended for adolescents, children, pregnant women, or individuals with pre-existing health conditions due to heightened risks.
Healthier Natural Alternatives Exist: For sustained energy, focus on proper nutrition, adequate sleep, hydration, and exercise instead of relying on artificial stimulants.

Common Side Effects from Caffeine and Stimulants

While many people turn to 5-Hour Energy for a quick boost, the shot's high concentration of stimulants can trigger various short-term side effects. A typical 2-ounce bottle contains up to 240 milligrams of caffeine, delivered in a concentrated dose that can hit your system more quickly than a standard cup of coffee.

Some of the most frequently reported adverse effects include:

Jitters and Anxiety: High doses of caffeine stimulate the central nervous system, leading to feelings of restlessness, nervousness, and even full-blown panic attacks, particularly in those with pre-existing anxiety disorders.
Insomnia and Sleep Disruption: As a potent stimulant, caffeine interferes with your natural sleep cycle. Drinking 5-Hour Energy too late in the day can make it very difficult to fall or stay asleep, perpetuating a cycle of fatigue and reliance on stimulants.
Increased Heart Rate and Palpitations: The stimulating effects on the cardiovascular system can cause a racing or pounding heart. This is especially risky for individuals with heart conditions or hypertension.
Digestive Issues: Many users experience gastrointestinal problems like nausea, stomach cramps, and diarrhea. Consuming the shot on an empty stomach can exacerbate these symptoms.
Headaches: While caffeine is sometimes used to treat headaches, overconsumption or withdrawal can trigger them. The constriction and dilation of blood vessels in the brain linked to caffeine intake is often the cause.

The Post-Energy Crash

One of the most notable side effects is the post-consumption crash. After the stimulant effect wears off, many users report feeling more fatigued and sluggish than before, a direct result of overstimulating the nervous system and adrenal glands. This can lead to a cycle of dependency where you feel you need another shot just to return to 'normal'.

Risks from Other Ingredients and Overconsumption

Beyond caffeine, 5-Hour Energy contains other ingredients that can pose health risks, particularly when consumed in excess or by sensitive individuals. A single serving contains extremely high percentages of daily value for certain B-vitamins, including B6 and B12.

High B-Vitamins: While B-vitamins are generally water-soluble and any excess is typically flushed out, chronic overconsumption can lead to issues. High doses of Niacin (Vitamin B3) can cause a harmless but uncomfortable 'niacin flush' (skin redness and hot sensation). More seriously, very high, long-term intake of Vitamin B6 can cause nerve damage. High B3 has also been linked to liver toxicity.
Artificial Sweeteners: 5-Hour Energy uses sucralose, an artificial sweetener, to avoid sugar. Some studies suggest high intake of artificial sweeteners may impact gut bacteria and lead to cravings, although more research is needed.
Cardiovascular Events: In severe cases of overconsumption, especially when combined with pre-existing heart conditions, energy shots have been linked to serious cardiovascular events like irregular heartbeat, heart attack, and cardiac arrest.
Kidney Issues: The high caffeine content can act as a diuretic, potentially contributing to dehydration. This, combined with a high metabolic load from other ingredients, can stress the kidneys over time.

Comparison: 5-Hour Energy vs. Natural Boosters


Feature	5-Hour Energy	Natural Alternatives	Risk Profile
Energy Source	High-dose synthetic caffeine, B-vitamins, amino acids	Balanced diet, hydration, exercise, natural caffeine from sources like green tea or coffee	High risk; relies on artificial stimulation that can lead to crashes and other side effects
Ingredient Purity	Contains artificial flavors and preservatives, sucralose	Whole foods, water, and herbal teas. Minimal to no artificial additives	Low risk; provides sustained energy without synthetic ingredients
Effect on Heart	Increases heart rate and blood pressure, potentially to dangerous levels	Moderate exercise and proper hydration can improve cardiovascular health over time	High risk for sensitive individuals; potential for serious cardiac events with abuse
Dependency	High potential for physical and psychological dependence	Promotes healthy habits that reduce reliance on external stimulants	Low; aims to address the root cause of fatigue, not just mask it
Vitamin Levels	Extremely high synthetic B-vitamin dosages, potentially toxic in excess	Vitamins absorbed from food are in healthier, balanced amounts	Can be risky; excessive intake of certain B-vitamins like Niacin and B6 can have adverse effects

Who Should Avoid 5-Hour Energy?

Certain individuals should be particularly cautious or completely avoid 5-Hour Energy and other highly concentrated energy shots:

Adolescents: Developing bodies are more susceptible to high caffeine doses, which can negatively affect cardiovascular and neurological systems. The American Academy of Pediatrics advises against energy drink consumption for children and teens.
Pregnant or Nursing Women: Caffeine can cross the placenta and affect a fetus, and some compounds may pass into breast milk. High caffeine intake has also been linked to miscarriages in some reports.
Individuals with Pre-existing Conditions: Those with high blood pressure, heart disease, anxiety disorders, liver issues, or diabetes should not consume these products without a doctor's approval.
Those on Medication: Energy drinks can interact with certain prescription medications, making it crucial to consult a healthcare provider.

Conclusion: Prioritize Natural Energy for Sustained Health

While 5-Hour Energy promises a convenient and quick solution to fatigue, the list of potential side effects and health risks is significant, especially with regular or excessive use. From common issues like anxiety and insomnia to more serious cardiac events and organ damage, the stimulant-heavy formula is not a benign solution for low energy. The high doses of synthetic caffeine and vitamins put stress on the body and can lead to a dependency cycle and burnout. Instead of reaching for a shot, a healthier and more sustainable approach involves addressing the root cause of fatigue. Prioritizing proper hydration, a balanced diet, adequate sleep, and regular exercise offers a far safer path to sustained energy and overall well-being.

Healthy Ways to Boost Energy

Get Enough Sleep: Aim for 7–9 hours of quality sleep per night.
Stay Hydrated: Drink plenty of water throughout the day, as dehydration can cause fatigue.
Balanced Nutrition: Eat regular, balanced meals rich in protein, fiber, and complex carbohydrates to maintain steady blood sugar and energy levels.
Physical Activity: A quick walk or light exercise can naturally increase serotonin and endorphin levels, improving mood and energy.
Herbal Teas: Consider green tea or yerba mate for a more moderate caffeine boost accompanied by other health benefits.

For more in-depth information on the health effects of energy drinks, consult resources like the National Institutes of Health.

Frequently Asked Questions

Yes, chronic, daily consumption of 5-Hour Energy can lead to dependency, disrupt natural energy metabolism, cause adrenal burnout, and increase the risk of serious health issues like cardiovascular damage and kidney problems.

The 'niacin flush' is a common, though harmless, side effect caused by the high dose of Vitamin B3 (Niacin) in 5-Hour Energy, which can cause temporary skin redness and a hot, tingly sensation. While not dangerous on its own, it is a sign of an excessive dose.

Yes, the high concentration of caffeine is a central nervous system stimulant that can induce or worsen feelings of anxiety, restlessness, and nervousness, particularly in individuals who are sensitive to caffeine.

The 'crash' occurs because the shot's caffeine and stimulants artificially rev up your system. Once these effects wear off, your body's energy levels plummet, often leaving you feeling more tired and sluggish than before you took it.

No, individuals with heart conditions, high blood pressure, or other cardiovascular issues should avoid 5-Hour Energy. The high caffeine content can dangerously increase heart rate and blood pressure, leading to palpitations, heart attacks, or other adverse events.

While B-vitamins are important for energy metabolism, the extremely high doses in 5-Hour Energy do not provide extra energy and any excess is simply excreted. Moreover, chronic overconsumption can potentially harm the liver and nerves.

Better alternatives include prioritizing sleep, staying hydrated with water, eating a balanced diet, and engaging in regular exercise. For a moderate caffeinated option, green tea or black tea is a safer choice.