Why Does Pre-Workout Make Me Feel Sick?

You’re not alone if you’ve ever felt sick after taking pre-workout. In fact, it’s a pretty common side effect. Here’s why it happens and what you can do about it.


Pre-workout supplements are a popular way to get a boost of energy and focus before you hit the gym. It’s normal to expect some mild short-term side effects after taking a pre-workout supplement, such as increased heart rate, increased mental alertness, or enhanced physical performance. However, if you are experiencing severe or prolonged symptoms of sickness after using these supplements, it’s important to take a closer look at what might be going on. In this article, we’ll examine the common causes of feeling sick after pre-workout supplementation as well as ways to mitigate these risks. By understanding why you may be feeling sick and how to prevent it in the future, you can continue using these supplements safely and effectively.

What is Pre-Workout?

Pre-workout supplements are generally taken to improve performance, in terms of both endurance and strength. They typically contain caffeine, creatine and other stimulants like B Vitamins, Beta-Alanine and Taurine. Many also include amino acids, extracts from plants such as green tea extract or guarana, as well as sweeteners and flavorings. Depending on the brand, these supplements can provide an energy boost for a workout and may help with endurance and anaerobic performance.

The potential side effects of pre-workout supplements can vary depending on the ingredients contained in them. Some users may experience increased heart rate, dizziness, nausea or jitters due to high levels of caffeine or stimulants contained within the supplement. Additionally, some athletes have reported dehydration due to excess sweating caused by the supplement’s overstimulation of their nervous systems. It is important that any pre-workout supplement is taken in accordance with its instructions as potentially serious health risks can occur if not used as directed.

Causes of Pre-Workout Sickness

Feeling sick after taking pre-workout supplements is a common problem that many people encounter. Pre-workout supplements contain a number of stimulants and ingredients that can cause adverse reactions in some people. In this article, we’ll explore some of the possible causes of pre-workout sickness, as well as some tips on how to avoid it.


One of the most common causes of pre-workout sickness is dehydration, which is the loss of fluids from the body. Dehydration occurs when you fail to replace fluids lost during sweating, exercising, or other activities. Symptoms can include fatigue, headaches, dizziness, and nausea.

For athletes and active individuals training at a high intensity for extended periods of time, dehydration can be an issue due to increased sweat rates and fluid loss from heavy breathing. A single hour of high-intensity activity can result in a significant water loss from your body. When dehydration strikes sudden onset symptoms such as nausea and vomiting may accompany the usual dehydration side effects.

Pre-workout supplements can also contribute to dehydration due to their diuretic properties which stimulate urine flow and excretion of fluids from the system faster than normal rates. Stimulants such a caffeine are also powerful diuretics that impair water balance in your body which can lead to symptoms such as lightheadedness or nausea prior to exercising or competing at an event when over consumed. It is essential that athletes adequately hydrate prior to participating in activities while they are supplementing with pre-workout products although it is important for everyone else too!

Caffeine Sensitivity

Caffeine sensitivity is a common cause of feeling sick when taking pre-workout. While caffeine is usually associated with an energy boost, people who are sensitive to the stimulant may experience adverse effects, including stomach upset and nausea. Being aware of your own unique response to this stimulant can help prevent feeling unwell when you take pre-workout before working out.

Caffeine doses can vary significantly in various pre-workout supplements, with some containing up to 300 milligrams per serving. Since individual tolerance levels vary widely, it’s important to check the label carefully and start with a low dose until you determine what amount works best for you. People who have overindulged in caffeine (greater than 500 mg) have reported feeling jittery or anxious and having difficulty focusing on their workouts.

In addition to caffeine content, other ingredients used in some pre-workout supplements may also play a role in causing feelings of sickness before hitting the gym. Stimulants like guarana and synephrine can be highly potent and might lead to reactions like nausea if one’s body isn’t used to them. Other ingredients such as artificial sweeteners, colorings or preservatives can also irritate the stomach or produce other adverse side effects like dizziness or restlessness.

Overdose of Stimulants

The main cause of pre-workout sickness is an overdose of stimulants. Stimulants are substances that have the effect of increasing alertness, physical energy, and cognitive function. Common stimulants found in pre-workouts include caffeine, synpherine, and other biting herbs like guarana or green tea extract. Some pre-workouts may even contain proprietary mixtures or blends featuring dangerous amounts of stimulants, including ingredients that have not been approved for use in dietary supplements.

When too much of a stimulant is taken, severe symptoms can occur. These generally start with a sense of unease or general discomfort and can progress to anxiety, rapid heartbeat, dizziness and nausea. In more serious cases even more symptoms like chest pains and headaches may occur. It is important to remember that everyone metabolizes stimulants differently; some people may be at higher risk for becoming sick from consuming pre-workouts than others are — so it’s worth paying attention to your body after consuming these supplements.

Finally, if you’re in the gym for an intense session it pays to forego the pre-workouts completely in favour of nourishing snacks such as bananas and nutrient packed smoothies instead — these can provide ample energy with fewer risks associated with large doses of stims!

Ingesting Too Much Sugar

If you experience pre-workout nausea, it may be due to the sugar content found in many pre-workout supplements. While sugar is a form of energy for your body, consuming too much can make you feel sick. Sugar is often added as a sweetener or flavoring agent to pre-workouts and these ingredients can cause an upset stomach. When the stomach is stressed with extra sugar, it can secrete acids that are more likely to cause nausea. Many studies have found that when people exercise after ingesting large amounts of sugar they tend to experience more nausea than when they exercise without the added sugar. To help prevent pre-workout related nausea it is important to check the ingredient labels of pre-workouts and watch out for any added sugars or sources of fructose.

How to Avoid Pre-Workout Sickness

Pre-workout supplements are a great way to increase your energy levels before a long workout. Unfortunately, some people may experience a range of side effects, such as nausea, dizziness, or stomach discomfort. In this article, let’s look at why this can be the case and how to avoid pre-workout sickness.

Drink Plenty of Water

Proper hydration is essential for overall health and performance, but it’s especially important when you’re getting ready to work out. Dehydration can impair physical performance and lead to fatigue, nausea, headaches and lightheadedness. Consuming adequate amounts of water before and during exercise can help minimize the risk of pre-workout sickness. Even mild dehydration of as little as 2% of your body weight can significantly impact your physiological functioning and energy level.

When you drink water regularly throughout the day, pre-exercise hydration should not be an issue; however it’s still important to top off your body’s reserves before exercising. Drinking 17-20 ounces of water an hour before exercise is a good guideline for hydration, but it really depends on individual sweat rates, fitness level and activity type. Training in hot or humid conditions will increase sweat rates and require more frequent hydration during activity. The American College of Sports Medicine recommends drinking 16 fluid ounces (about 500ml) 2 hours before working out followed by 6-8 fluid ounces (about 200ml) about 10 minutes prior to exercise for optimal results.

Start With a Low Dose of Caffeine

When starting to use a pre-workout supplement for the first time, it is important to begin with a low dose of caffeine. This allows the body to gradually acclimate to the stimulant rather than trying to adjust immediately, which can cause feelings of nausea. Start with one scoop, or the amount recommended on the label — usually half a scoop — and slowly increase your dosage over time if needed.

Additionally, it is important to ensure that you are only using quality pre-workout supplements that contain no additional stimulants or ingredients that may not agree with your body chemistry. Other ingredients such as taurine, guarana and even B vitamins can be potential sources of nausea or other stomach issues if taken in high doses. Taking pre-workout supplements without reading the label or understanding how each ingredient may affect your body can put you at risk for feel ill before working out.

Finally, it’s wise to take your pre-workout about 30 minutes before beginning physical activity and never on an empty stomach as this can add stress and cause feelings of queasiness. Eating a light snack before taking your supplement will help eliminate any potential dehydration or hypoglycemia that could be causing pre-workout nausea.

Check the Ingredients

It is important to check the ingredients list of any pre-workout you are considering for potential causes of nausea or stomach upset. Certain ingredients, such as caffeine, taurine, guarana extract and synephrine (an extract from citrus fruit), can cause feelings of nausea or dizziness if taken in too large a quantity. Furthermore, some supplements may contain high levels of added sugars which can also cause nausea. Look through the full list of ingredients on the label to become aware of any substances that may trigger an upset stomach and make sure you adhere to dosage directions carefully.

Take a Break From Pre-Workout

Pre-workout supplements are designed to give you an extra boost of energy for your workout. Unfortunately, they can also leave you feeling jittery or nauseous. The most important way to prevent pre-workout sickness is to take regular breaks from pre-workout supplements. However, there are several other strategies that you can use to manage any symptoms that arise when taking these supplements in moderation:

1. Start with a small dose – If you’re new to pre-workout supplements, start with a smaller dose than what is typically recommended on the label. This will help your body get accustomed to the ingredients and reduce any potential physical reactions like nausea.

2. Drink plenty of water – Make sure you drink enough water while taking pre-workouts and afterwards as well, as dehydration can often lead to feelings of nausea and dizziness.

3. Stick with trusted brands – High-quality brands are essential in order to avoid unsafe ingredients or substances that may cause adverse reactions such as dizziness or nausea. Be sure to read labels carefully and research ingredients before consuming anything new.

4. Avoid caffeine sensitivity triggers – Pre-workouts often contain caffeine, which is known for triggering sensitivities in some individuals such as headaches, jitteriness, upset stomach or rapid heartbeat—all symptoms associated with pre-workout sickness. To avoid these triggers, consider purchasing natural caffeine alternatives or reducing the amount of caffeine that’s added into your supplement.

5. Take it easy during your workout – Start off slow and gradually increase the intensity of your exercise session rather than pushing yourself too hard at once because this could make any existing physical sensations worse resulting in a full blown episode of pre-study sickness!


Although pre-workouts may provide short-term boosting effects to your energy and performance during workouts, they also come with some potential side effects. Pre-workouts are made up of multiple ingredients, some of which can cause an upset stomach, nausea and dizziness due to their stimulant properties. Other factors like excessive caffeine intake, artificial sweeteners and existing health conditions may also contribute to the adverse side effects associated with pre-workout drinks.

It’s important to take special care when choosing the right pre-workout supplement for you so that you stay safe and get the most out of your workout session without experiencing any unwanted symptoms before or after taking it. Pay close attention to the ingredients in pre-workouts supplements so that you have an understanding of what is inside and how it affects your body. And consider testing one product at a time until you’ve perfected a combination that hits all your performance needs without causing adverse reactions or any uncomfortable side effects.

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