Pre Workout Crash – Why Does Pre Workout Make Me Tired?

Pre workout supplements are designed to give you an extra boost of energy and focus for your workout. However, they often contain high levels of caffeine and other stimulants. This can lead to a ‘crash’ making you feel tired.

If you take pre workout supplement you might have wondered why does pre workout make me tired. This is common in people who take pre workouts and is also known as Pre Workout Crash.

If you’re someone who takes pre workout and finds that you’re tired after taking it, then this article is for you. We’ll be taking a look at why pre workout can make you feel tired and we will also be discussing some ways to avoid pre workout crash.

What is Pre Workout?

Pre-workout is a type of supplement designed to increase energy, focus, and stamina [1, 2]. It usually contains a combination of vitamins, minerals, and stimulants such as caffeine, creatine, yohimbine, and beta-alanine [3]. Pre workout supplements are taken by people to enhance performance and give them an extra boost of energy and power. 

These supplements come in many different forms such as pills, powders, and drinks. You may find that pre workout increases your energy, your focus, and your stamina, but it may also leave you feeling tired after it wears off. This post-workout fatigue is commonly referred to as a “crash”.

Why Does Pre Workout Make Me Tired? Causes of Pre Workout Crash

pre workout crash
Tero Vesalainen/iStock

There are some reasons why pre workout can make you feel tired afterward causing fatigue known as pre workout crash. 

1. Caffeine Tolerance

Caffeine is the main ingredient in most pre workouts. It is a stimulant that can increase energy levels, focus, and endurance. Caffeine can also have a positive effect on performance and weight loss [4], so many people use it as a way to get an edge in their workouts. 

However, consuming too much caffeine can lead to a ‘crash’ afterward. This can make you feel tired, irritable, and even nauseous which are common side effects of caffeine [5]. It’s a common phenomenon among people who take pre workouts and can lead to a lot of discomfort.

Pre workout supplements usually contain more than 200 to 400mg of caffeine. Some of the pre workouts contain even more than 400mg of caffeine. The FDA recommends no more than 400 milligrams of caffeine in a day [6]. If you take pre workout supplements high in caffeine and also consume foods containing caffeine you can easily cross the 400mg limit which can result in various side effects.

The higher the doses of caffeine in the pre workout supplements the more chances are of pre workout crash. People develop caffeine tolerance which happens after consuming high doses of caffeine constantly. This results in people becoming desensitized to caffeine’s benefits.

This is simply why you might feel tired sometimes after consuming high amounts of caffeine through pre workout supplements or even from other sources.

2. Diet

Your diet plays an important role in affecting your energy levels. If you do not consume enough calories you will most likely be tired the whole day.

Research has shown that pre workout can suppress your appetite because of caffeine and the other stimulants added to it [7, 8].

When your appetite is suppressed you will not consume enough calories which can result in less energy levels. Low energy levels are also common in people following a calorie deficit.

Make sure to consume enough calories to stay energized and reduce the effects of pre workout crash.

3. Workout Performance

Pre workout supplements can be beneficial for people who want to get an extra energy boost in their workouts. It can also help improve focus and performance in the gym. 

As pre workout supplements help you perform better and harder in your workouts, it is common to feel tired, fatigued, and sore after working out.

When normal fatigue is combined with pre workout crash you will feel higher levels of tiredness, and fatigue and might even experience nausea and headaches.

If you are experiencing pre workout crash, it is suggested to lower your workout intensity for a while and you can get it back up after things get normal after some time.

4. Dehydration

Dehydration is one of the side effects of taking pre workout supplements. As we know, pre workouts contain ingredients that can help in boosting energy levels and improve workout performance. These ingredients can help you push harder and longer in your workouts.

When your workout intensity is higher you are more likely to sweat which means your body will lose water causing you to become a little dehydrated.

Not only that but some of the ingredients included in pre workout supplements like caffeine and which is a diuretic [9], can cause you to pee more than usual leading to dehydration in some cases.

Dehydration can cause headaches, and fatigue, and increase soreness after workouts. So, make sure to be hydrated and drink enough water.

5. Spike in Blood Sugar Levels

Another side effect of pre workout supplements is a spike in blood sugar levels. Many pre workouts contain artificial sweeteners and added flavors which can affect your blood sugar levels.

Sudden increases in blood sugar levels can cause fatigue, exhaustion, headaches, and dizziness. A spike in blood sugar levels is just another reason why you may feel more tired after taking pre workout supplements and experience a pre workout crash.

6. You Might Be Taking Too Much Pre Workout.

Another possible reason you’re feeling tired after taking pre workout is that you’re taking too much. Pre-workouts typically come in servings of around 10-20g. Taking too much could lead to an overdose of caffeine or other ingredients, which could then cause a crash. 

It’s important to check the label before taking a pre workout and make sure you’re not taking too much. Some pre workouts contain very high levels of caffeine, so it’s important to approach them with caution. Try sticking to the recommended dosage and not going over it. 

You’re Not Alone if You’ve Ever Felt Tired After Taking a Pre Workout Supplement.

It’s not uncommon for people to feel tired after taking a pre-workout supplement, especially if it contains caffeine. Caffeine usually has a stimulating effect, but in some cases, the effects can be too strong. 

When this happens, people can experience a “crash”. This can cause an array of effects such as fatigue, headaches, nausea, and difficulty concentrating. 

There are several reasons why you might be experiencing this crash. Caffeine is most likely the culprit, but there could also be other stimulants in pre workouts that could be contributing to the crash. 

How to Avoid Pre Workout Crash

why does pre workout make me tired
Image- Liudmila Chernetska/iStock

Take Stimulant-Free Pre Workout Supplements

Stimulant-free pre workouts also known as non-stim pre workouts are the ones that do not contain any stimulants. As the main culprit behind pre workout crashes could be considered the stimulants added in pre workout supplements, trying stimulant-free pre workouts can help in avoiding and stopping fatigue after taking pre workouts.

Eat Enough Calories

As mentioned above, one of the reasons for pre workout crash is your diet. If your diet contains a lesser amount of calories than required, then you are most likely going to experience a pre workout crash. 

To avoid it, you need to make sure you eat enough calories that your body needs to maintain your energy levels. The number of calories you will need to eat will depend upon your fitness goals but it is generally recommended to eat more calories if your workout is higher in intensity as you are also going to burn a lot of calories.

Reduce Your Pre Workout Doses

If you are facing pre workout crashes then you might need to lower your doses for a few weeks and test your tolerance and see if it works out.

Reducing your pre workout doses for a few weeks can help your body in resetting your tolerance and stop pre workout crashes.

Try Reducing The Amount of Caffeine You Take In

One way to avoid the pre workout crash is to reduce the amount of caffeine you take in. Caffeine is the main ingredient in most pre-workouts, so if you find that you’re crashing afterward, then this could be the culprit. You can try reducing the amount of caffeine in your diet by half or even a quarter. This should help reduce the intensity of the crash. 

If reducing your caffeine intake doesn’t work out you could try to completely cut off caffeine from your diet as it will help in resetting your body’s tolerance to caffeine.

Cycle Your Pre Workout

If you’ve been using pre workouts for an extended period of time and consistently feel fatigued afterward, then you should consider taking a break. This could be done by cycling your pre workout. 

Pre workouts can be addictive, so your body might have become used to the caffeine or other stimulants and develop tolerance. This can lead you to consume higher doses of caffeine and it makes the situation even worse. Instead of making the doses higher, you should try to cycle your pre workout to avoid and stop tolerance.

Cycling your pre workout allows taking a break from pre-workouts to help reset your system and give you a renewed sense of energy. 

Simply cycling your pre workout involves taking pre workout supplements for 4-6 weeks and then stopping to take them for around 2-3 weeks to reset your tolerance. This process is cyclic and should help you avoid any pre workout crashes.

Some Frequently Asked Questions (FAQs)


Pre workouts are taken as they provide an extra energy boost, and improve workout performance and focus. But most pre workout contains stimulants like caffeine which can result in tiredness after working out also known as a crash.

Not only caffeine but there could be some other reasons for pre workout crashes as well like your diet, workout performance, a spike in blood sugar levels, and dehydration. 

There are many ways you can try to stop and avoid crashes, but using stimulant-free pre workout is the main way you can avoid pre workout crashes.

Pre workout supplements are beneficial and they do work but it is important to consider checking on the doses of their ingredients and make sure to keep a track of your intake to avoid unnecessary side effects.

More Pre-Workout Supplement Guides

Pre Workout vs Fat Burner – Differences and Which Is Better?

Creatine Vs Pre Workout – Differences and Which is Better?

Does Pre Workout Make You Poop? Explained

Can Pre Workout Cause Anxiety?

Can You Take Pre-Workout On An Empty Stomach? Boost Gains?

Expired Pre-Workout: Does Pre-Workout Go Bad?


  1. Martinez, N., Campbell, B., Franek, M. et al. The effect of acute pre-workout supplementation on power and strength performance. J Int Soc Sports Nutr 13, 29 (2016).
  2. Outlaw JJ, Wilborn CD, Smith-Ryan AE, Hayward SE, Urbina SL, Taylor LW, Foster CA. Acute effects of a commercially-available pre-workout supplement on markers of training: a double-blind study. J Int Soc Sports Nutr. 2014 Aug 15;11:40. doi: 10.1186/s12970-014-0040-0. PMID: 25302053; PMCID: PMC4190923.
  3. Jagim AR, Harty PS, Camic CL. Common Ingredient Profiles of Multi-Ingredient Pre-Workout Supplements. Nutrients. 2019 Jan 24;11(2):254. doi: 10.3390/nu11020254. PMID: 30678328; PMCID: PMC6413194.
  4. Dulloo AG, Geissler CA, Horton T, Collins A, Miller DS. Normal caffeine consumption: influence on thermogenesis and daily energy expenditure in lean and postobese human volunteers. Am J Clin Nutr. 1989 Jan;49(1):44-50. doi: 10.1093/ajcn/49.1.44. PMID: 2912010.
  5. Evans J, Richards JR, Battisti AS. Caffeine. [Updated 2022 Nov 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:
  7. Schubert MM, Irwin C, Seay RF, Clarke HE, Allegro D, Desbrow B. Caffeine, coffee, and appetite control: a review. Int J Food Sci Nutr. 2017 Dec;68(8):901-912. doi: 10.1080/09637486.2017.1320537. Epub 2017 Apr 27. PMID: 28446037.
  8. Nasr L, Sacre Y, Attieh R, Mannan H. Association between the Timing of Pre-Workout Macronutrient Intake and Rated Appetite among Resistance-Trained Adults in Jbeil, Lebanon. Int J Environ Res Public Health. 2023 Jan 29;20(3):2399. doi: 10.3390/ijerph20032399. PMID: 36767765; PMCID: PMC9915277.
  9. Lohsiriwat S, Hirunsai M, Chaiyaprasithi B. Effect of caffeine on bladder function in patients with overactive bladder symptoms. Urol Ann. 2011 Jan;3(1):14-8. doi: 10.4103/0974-7796.75862. PMID: 21346827; PMCID: PMC3036994.

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