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Why Pre Workout Makes You Sick (+How To Prevent It!)

If you’re wondering why pre workout can make you sick, then you’ve come to the right place.

In this article, we dive deeper into:

  • Why pre workout makes you sick
  • 7 tips to get rid of pre workout sickness
  • What to do if you’re already experiencing pre workout sickness
  • Other common questions regarding pre workout use and nausea
woman being sick after taking pre workout

Why Pre Workout Makes You Sick (& How To Get Rid Of Pre Workout Sickness)

Pre workout supplements contain a wide range of ingredients, which can make it hard to pin point the exact reason for why it makes you feel sick.

That said, there are some common ingredients in pre workout which have been shown to cause pre workout nausea.

The 7 reasons why pre workout makes you sick are:

  • Having too much caffeine
  • Having too much creatine
  • Having too much l-citrulline
  • Having too much glycerol
  • Taking pre workout on an empty stomach
  • Taking too much pre workout
  • Having too much or too little water

Let’s take a look at these in some more detail.

1. Having Too Much Caffeine

Caffeine is the most widely consumed drug in the world.

Many pre workouts contain a large dose of caffeine to help improve focus and performance.

Now, I’ve always wondered why I feel a bit sick after a strong cup of coffee, and it turns out caffeine may be the culprit.

In one study, 12 subjects received a placebo, 250mg of caffeine, and 500mg of caffeine at different intervals.

(The study was blind, meaning the subjects didn’t know what they were taking at each interval.)

The results showed that nausea, anxiety and irritability were much more common in the subjects after taking the 500mg dose.

So with many pre workouts containing 400mg of caffeine, this explains why it may make you feel sick.

How To Fix It:

First, you should know exactly how much caffeine is in your pre workout supplement.

Knowing the amount of caffeine will help you monitor your total caffeine intake throughout the day.

The half-life of caffeine is around 6 hours.

In other words, if you drink a coffee at 9am, you’ll still have half of the caffeine in your system at 3pm!

So if your pre workout contains a large amount of caffeine, you should stay clear from other caffeine sources to keep your blood levels of caffeine at a sensible range.

2. Having Too Much Creatine

Creatine is a natural substance found in red meat and fish, that our bodies break down into ATP – our cells’ energy currency.

It’s added to many pre workout supplements as it’s safe, cheap and helps you squeeze out more reps.

Interestingly, some research suggests that creatine may lead to nausea.

In one study, 175 ALS patients consumed either 10g of creatine or a placebo over an average period of 310 days.

The results showed that 23% of the creatine group experienced nausea.

How To Fix It:

If you believe that creatine is the cause of your pre workout sickness, the sensible option is to choose a different pre workout supplement that doesn’t contain creatine.

But if you’ve already bought a pre workout with creatine, then it makes sense to avoid other sources of creatine throughout the day.

3. Having Too Much L-Citrulline

L-Citrulline is an amino acid that’s usually included in pre workout in the form of Citrulline Malate.

(This is L-Citrulline bounded to malic acid.)

When consumed, some of the L-Citrulline is converted to Arginine, which helps increase nitric oxide levels.

This helps improve blood flow and the widening of arteries, which is why many pre workouts give you an epic pump.

A study of 41 obese asthmatics investigated the effects of high dose L-Citrulline on asthma control.

According to the results, 41% of the subjects experienced mild nausea.

How To Fix It:

The best option is to opt for a pre workout that contains minimal L-Citrulline.

If that’s not possible, then ensure that none of the other supplements you take in that day contain L-Citrulline.

If it’s the taste that puts you off, you could even try mixing your pre workout in a smoothie to sweeten it up and give you some carbs before hitting the gym.

4. Having Too Much Glycerol

Around a quarter of all pre workout supplements are believed to contain glycerol, thanks to its ability to improve muscle pumps.

However, some research suggests that glycerol can induce feelings of nausea.

The current recommendation for glycerol supplementation is to take 1g/kg of body weight of it 1-2 hours before exercising.

Since pre workout is usually taken within 30 minutes of exercising, ingesting glycerol too close to your workout may explain why you feel sick after pre workout.

That being said, most pre workout supplements contain a relatively small amount of glycerol, so it’s unlikely to be the main cause of pre workout sickness.

How To Fix It:

Like creatine, glycerol can impact your body water levels, so ensure to stay hydrated throughout the day if your pre workout contains glycerol.

If that fails, then your best option is to take a different pre workout that doesn’t contain glycerol.

5. Taking Pre Workout On An Empty Stomach

Taking pre workout on an empty stomach may increase the chances of you feeling sick.


Well, taking it on an empty stomach means the pre workout is absorbed much quicker in your stomach.

So the caffeine, creatine, l-citrulline, and glycerol levels in your blood rise more rapidly.

The outcome of this is feeling the effects of pre workout much more intensely.

(It’s the same reason why drinking alcohol on an empty stomach gets you a lot drunker – your blood alcohol levels rise rapidly.)

Also, there seems to be a lot of anecdotal reports of people feeling nauseous after taking pre workout on an empty stomach.

How To Fix It:

Have a small snack 30 minutes before taking your pre workout drink.

If your current diet doesn’t allow this, then split your last meal into two smaller meals and eat one of them an hour before working out.

If you usually work out fasted, then take a handful of nuts or a small portion of fruit intra workout to help stabilize your blood sugar levels.

But there’s a bit of a balancing act here…

If you have too much food, you may be more likely to puke when working out (especially legs!) so use some common sense.

6. Taking Too Much Pre Workout

The more pre workout you take, the more likely you are to feel nauseous.

(Assuming the pre workout contains caffeine/creatine/l-citrulline/glycerol of course!)

Going back to caffeine study, subjects were much more likely to experience nausea at doses of 500mg.

And with many pre workouts containing up to 400mg of caffeine per serving, you can very easily exceed this if you take more than the recommended amount.

For this reason, I’d generally avoid taking pre workout twice a day.

How To Fix It:

Too much of a good can thing becomes a bad thing.

And the same can be said for pre workout – you’re much more likely to suffer from nausea if you take too much of it.

Likewise, the less pre workout you take, the less adverse effects you’ll experience.

It’s important to follow the dosage recommendations and serving size on the product label, as well as instructions on consuming the supplement.

Make sure you double check these every time you use a different pre workout.

7. Having Too Much or Too Little Water

Something as simple as using too much water in your pre workout drink can cause sickness.

If you’re working out with a belly that’s too full, all the water could be sloshing around leading to further abdominal discomfort.

On the other hand, taking your pre workout drink with too little water can make you feel sick due to the bad taste of pre workout.

Many of the ingredients found in pre workout, like L-Citrulline have a sharp, bitter taste. To combat this, pre workout companies will often add a ton of artificial sweeteners which can lead to an upset stomach and feelings of nausea.

How To Fix It:

Most pre workout supplements will have recommendations for the amount of water you should be using per serving, so follow these carefully.

It’s best to start with a lower amount, and if the taste is too strong, add a bit more until it’s easier to drink.

Remember not to chug your pre workout drink too fast, as this can also lead to nausea.

What To Do If You’re Already Experiencing Pre Workout Nausea?

One of my favorite quotes is: An ounce of prevention is worth a pound of cure.

And it’s oh so applicable here.

The best way to stop feeling sick after taking pre workout, is to prevent feeling sick in the first place!

But what if you’re currently experiencing pre workout sickness?

Try these tips:

  • Take It Easy
  • Have a Snack
  • Rest Up at Home

Take It Easy

If the nausea is mild, then you should be able to work out with minimal issues, but remember to take it easy.

Do some light cardio and start off with some light warm up sets.

If the nausea subsides, then carry on with your workout as normal.

(Although you should probably avoid heavy movements which put pressure on your core, like squats and deadlifts!)

If you start exercising and the nausea doesn’t go away, it’s probably best to stop exercising for the day.

Have A Snack

banana pre workout snack

Sometimes, a small snack like a banana or a protein bar can help settle your stomach.

Give this a try, and you start feeling better, feel free to start your workout and remember to take things slow and steady.

Rest Up At Home

If you’ve started a light warm up and eaten a snack but don’t feel any better, you should rest up at home as a precaution.

After all, you won’t gain anything from your workout if you can only push yourself at 30% of maximum effort without wanting to puke.

Frequently Asked Questions

How Long Does Pre Workout Sickness Last?

There are many factors which can affect the duration of pre workout sickness.

How much pre workout did you take?

Have you taken any other forms of caffeine, i.e. coffee, at the same time as your pre workout?

Have you taken creatine in addition to pre workout?

These are just some things that can play a part in the length of pre workout sickness.

But roughly speaking, pre workout sickness lasts anywhere between 30 mins and 3 hours for most people.

The more pre workout you take, the longer the sickness will last.

Do All Pre Workouts Make You Sick?

No – not all pre workouts make you nauseous.

Many pre workouts out there are free from caffeine/creatine/l-citrulline.

Since these are the culprits that make you feel sick, then you should feel fine after taking a pre workout that excludes these ingredients.

Should You Stop Taking Pre Workout If It Makes You Nauseous?

This depends on a few things.

First, how severe is the nausea?

If you feel just a tad queasy, and it doesn’t affect your workout, then you may be able to fight through it and accept it as a mild annoyance.

But if you feel on the verge of throwing up after taking it, then you should consider reducing the dose.

Reducing the dose should help, but if it doesn’t, then you may want to switch to a pre workout that’s free from caffeine/creatine/l-citrulline.

If that fails?

(Which I doubt it will…)

Then you should probably stop pre workout.

Should You Be Worried If Pre Workout Makes You Sick?

Not at all!

Worrying is a negative emotion which drains you of your energy.

This can reduce the intensity of your workout, which is the opposite of what you want after taking pre workout!

You also need to bear in mind that you’re in control of the situation.

You know exactly why you feel nauseous.

(Feeling sick may be worth worrying about if you don’t know the cause. But in this scenario, you do.)

Final Thoughts

In summary:

  • Some of the ingredients in pre workout, like caffeine, can cause sickness in high doses.
  • Sometimes, how you take your pre workout (i.e. how much you take) can determine whether you feel sick after pre workout.
  • There are many ways to get rid of pre workout sickness, including choosing a different pre workout that doesn’t have problem ingredients, and taking less pre workout.

That’s all for pre workout nausea, but perhaps you’re interested in funny pre workout names? Or does pre workout show on a drug test?

Hope this helped!