Pre workout is the go-to supplement nowadays thanks to its ability to improve focus, energy and fat loss.
Here’s everything you need to know about pre workout and nausea.
Does Pre Workout Cause Nausea?
Some pre workouts can cause nausea due to the high caffeine, creatine and L-Citrulline content. Studies have shown that these ingredients can cause nausea when taken in high doses.

In this article, we cover why some pre workouts cause nausea, whether taking pre workout on an empty stomach causes nausea, how to stop feeling sick after taking pre workout, and much more!
Which Ingredients In Pre Workout Can Cause Nausea?
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.
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.
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.
Does Taking Pre Workout On An Empty Stomach Cause Nausea?
Taking pre workout on an empty stomach may increase the chances of you feeling sick.
Why?
Well, taking it on an empty stomach means the pre workout is absorbed much quicker in your stomach.
So the caffeine, creatine and l-citrulline 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.
Does Taking Too Much Pre Workout Cause Nausea?
The more pre workout you take, the more likely you are to feel nauseous.
(Assuming the pre workout contains caffeine/creatine/l-citrulline 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.
Do All Pre Workouts Cause Nausea?
No – not all pre workouts cause nausea.
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 taking pre workout.
Should You Be Worried If You Feel Nauseous After Taking Pre Workout?
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.)
What Should You Do If You Feel Nauseous After Taking Pre Workout?
Ultimately, this depends on how nauseous you feel.
If it’s just a little queasy, then you can still workout as normal.
(But I’d definitely avoid training legs!)
Whereas if you feel like you could puke, you’re best off cutting your losses and skipping your workout.
The last thing you want when mid bench press is to end up choking on your sick!
How To Stop Feeling Sick After Pre Workout
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!
So with that in mind, here are a few ways to prevent feeling sick after pre workout.
Take it after you’ve eaten
As covered earlier, you’re much more likely to feel sick after taking pre workout on an empty stomach.
And so, you’re much less likely to be nauseous if you have your pre workout just after a meal.
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.
Use less pre workout
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.
Avoid taking additional caffeine/creatine
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 when taking pre workout, you should stay clear from other caffeine sources to keep your blood levels of caffeine at a sensible range.
Also, you might want to stop taking creatine on its own if there’s a fair amount of it in your pre workout.
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