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Pre Workout Side Effects
Are They Worth the Trouble?

Jason Hughes
Published by Jason Hughes
Fact checked by Markus Oliver, BHSc FACT CHECKED
Last updated: February 26, 2021

As a vegan health and fitness geek, I’m always looking for new ways to improve my diet and get more out of my exercising while avoiding harmful substances beyond just the animal ones.

In many cases, this leads me to fitness and dietary supplements designed to boost performance levels and help with weight loss. But in a market flooded with ineffective and sometimes harmful ingredients, I always caution on the safe side and have a chat with my dietician first.

For this post, I want to bring you my notes from that conversation. I’ll start with a brief section on what does pre workout do, and then dive right into some side effects and how to deal with them.

This will all help you make a decision if you’ve been asking yourself the same question I did: should I take pre workout as a health conscious vegan?

Let’s get right into it.

What is In Pre Workout Supplements?

Pre workout supplements

Basically, all vegan pre-workout supplements contain a similar set of ingredients, which include caffeine, creatine (more on this), citrulline, beta-alanine, and BCAA (branched chain amino acids) amongst others.

The different brands will, of course, include a variation of the amount used in the supplement, but they all have the same purpose; that is to boost your energy levels so that you will have more strength and stamina to be able to endure a hard workout session.

Mostly you will find them in the form of a powder that you mix with water into a shake. Time this for about 15 minutes before your training begins and you’ll notice some performance boosts.

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Believe it or not, but there are many different vegan pre-workouts produced by the supplement industry. However, the quality can vary a lot, so it’s not easy to know which is the right one for the best results. To make your choice easier, I have put together a list of recommendations for you to consider.

The best tip I can offer though, is always check out the information on the label and avoid anything that mentions “proprietary blend,” unless you receive a personal and trusted recommendation. (1)

What Does Pre-Workout Do To Your Body?

Bulky man with supplements

Pre-workout products help your body to increase available energy levels so that you can train harder and for longer. (2)

But you shouldn’t associate supplements as some form of doping, even though it does sound like it. Off-the-shelf vegan products are only produced with natural ingredients and are totally legal.

So does pre workout work? Don’t let your imagination run away with you and expect to have the strength of a WWE star, but you could expect a boost of between 10-25% in your performance.

And here is why they work.

1. Creatine-Based Pre-Workout


Creatine is needed so that muscle cells in your body can increase energy production.

The boost that creatine provides will give you the strength and stamina to perform at levels you haven’t seen before.

One study has shown a performance boost of more than 15% when using weights for resistance training.

This means a quicker build-up of muscles and the added advantage of burning up fat at the same time.

2. Caffeine-Based Pre-Workout

coffee bean

Most people take it purely for the mental stimulation, but there are significant metabolic benefits that make it a very effective fat burner. (3)

Most supplements contain the equivalent of 1-2 cups of coffee or about 150 mg of caffeine.

You definitely want to keep this in mind if you’re a coffee drinker as well, as you can quickly end up with the dreaded jotters

We'll talk about this more shortly.

3. Other Known Effective Ingredients

Although the above two ingredients are the most commonly used ones, there are many more to be found in a vegan dietary supplement.

  • Citrulline - This is a vitally important amino acid your body produces to help increase blood circulation. Taking a supplement prior to training will give you the boost you need for increasing your blood flow. This will then provide your muscles with the much-needed nutrition and oxygen for better pumps.
  • Sodium Bicarbonate - This is nothing other than household baking powder. While there is no conclusive scientific proof that it actually reduces acid buildup, some studies have shown a correlation. There is no harm whatsoever in taking it and even with a small possibility of it reducing the lactic acid in the muscles, it’s worth taking a chance.
  • L-theanine - When caffeine and L-theanine are combined, you will experience a boost in alertness and focus at the same time. It helps you stay motivated focused on your goals, both at the gym and at work as well. ​(4)​​​
  • BCAAs - ​"Branched-chain amino acid" is a protein which your body cannot produce, so it needs to be ingested with food. It has been scientifically proven that endurance improves while taking vegan BCAA, but the impact on muscle building is minimal. We had a good experience with Ready Fuel. If you're considering other options, check out our BCAA Solgar supplement review.

Now, let’s take a look at some negatives.

By accelerating ammonia clearance, supplemental citrulline postpones the inevitable decrease in muscle pH that happens during intense exertion.

Mike Roussell, Nutritional Consultant

Does Pre Workout Have Side Effects?

side effects

Yes, pre workout has some side effects including nausea, headaches, jitters, and insomnia.

However, while discussing side effects with people, I generally found that those who suffered any negative effects also suffered from allergies or intolerance to some ingredients.

That’s one of the reasons you should always read the labels on a product carefully to check that the product doesn’t contain anything that could cause an upset. If you spot something that has caused a problem before, then it’s best to avoid it altogether.

Of course, there is always the possibility of encountering a negative reaction to a product even when you haven’t previously had any problems; that’s why it’s important to immediately note any bodily reactions after taking a supplement.

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The main things to look out for are:

  • Nervousness and headaches are to be expected if your caffeine dose is too high. This can easily happen if you drink a lot of tea or coffee throughout the day and you might have experienced it before as feeling jittery.
  • Insomnia is another negative aspect of caffeine, so you need to be careful. This has happened to me on occasion where I went to the gym late in the evening. By the time I was finished and ready for bed the caffeine hadn’t worn off; bad idea.
  • Diarrhea is possible, but not so common. It may cause a laxative effect when caffeine, creatine and sodium bicarbonate are combined, and this all depends on the sensitivity of your digestive system.

Just reading these you might be wondering: is pre workout bad for you? The simple answer is no, it’s not bad for you, and the majority of people don’t suffer side effects. At the same time, if you do encounter some, then there are some tips you can follow to reduce them.

​Watch this video to learn more about its other side effects.


How To Get Rid Of Pre-Workout Side Effects

You can get rid of pre-workout side effects by eating before you take it, drinking more water and reducing the dose you take.

There should be no serious impact on your health with the above side effects, but they can be avoided or cured by following these simple steps.

1. Insomnia


Everyone experiences the effects of caffeine differently. I’m always amazed when friends offer me a cup of coffee late in the evening and mention that they’ve never had a problem with insomnia.

I, personally, avoid drinking coffee late in the afternoon or evening. What’s more, I don’t drink it at all in the afternoon when I plan on going to the gym.

If you know that coffee is the cause of your insomnia, you shouldn’t take any vegan pre-workout shake after 7 pm.

If this isn’t possible, then look for one that has a lower amount of caffeine or doesn’t contain any at all so that it won’t affect your sleep.

2. Diarrhea

Stomach Pain

This is possibly one of the most embarrassing side effects you can be faced with.

Normally, either intolerance to one of the ingredients or drinking pre workout on empty stomach is the cause of this. Knowing when to take pre workout shakes is the best solution.

Firstly, you should only drink a vegan supplement after eating something, even just a small snack. It’s generally not good to drink one if you’ve not eaten for hours.

Furthermore, start by only drinking half the recommended amount.

As your stomach adjusts to it, you can increase the amount accordingly.

3. Dehydration


Should you suddenly become thirstier than normal while exercising, maybe the substance combination in your supplement does not agree with you, or you took too much pre workout.

Some products are designed to target your reserve of glycogen, a resource of energy that fixes itself to water.

It’s better for you to drink something before your mouth goes dry and you begin to feel thirsty.

Once you reach this stage, you will find that it has a considerably negative influence on performance.

So it's really recommended to drink lots of water everyday.

When you have less fluid in your body, your heart has to work even harder to pump blood.

Amy Marturana, Health and Fitness Journalist

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4. Headaches

man having headache

Dehydration and high doses of caffeine are often the cause of headaches.

But there are other ingredients which expand your blood vessels, thereby helping to boost your blood circulation.

Generally, this effect is positive, but some people suffer from a sensitivity of this effect in the brain and experience headaches.

Vegan supplements don’t normally cause migraines, but consistent headaches should be taken seriously.

If it does happen, then just take a few days break. If it happens again, then you’ll need to consider a different option.

5. High Blood Pressure

High Blood Pressure

Naturally, a side effect of stimulants is that they are known to boost your heart rate, which in turn causes your BP to rise.

If you are already aware of problems with your blood pressure, you should completely avoid taking any form of stimulant.

If you’ve suffered with sporadic BP problems, then measure it before and after you work out.

Should it be considerably higher than normal, then you should look for a vegan product that is caffeine free.

Most of the time, high blood pressure can be avoided by eating foods high in fat and cholesterol.

6. Tingling Sensations

Tingling Sensations

Vitamin B3 and beta-alanine are two of many ingredients that cause sensitivity in some people, as they have a direct impact on your nervous system. (5)

It is possible that you’ll sense a certain amount of tingling in your body after taking a product containing these ingredients.

There is nothing abnormal about this, and it should stop after a short time.

I don’t consider it to be so problematic; it’s just a little distracting.

Just ignore it completely as it normally stops pretty soon after I start training.

It's better to take a moderated amount of Vitamin B3 and beta-alanine to avoid these tingling sensations.

Related: Our Recommended Beta-Alanine Supplements

Frequently Asked Questions


How often should I take pre-workout?

You should drink a pre-workout supplement once or twice a day depending on how often you exercise. Should you drink too much, you’ll start feeling jittery or unwell. Drinking too much also causes your heart rate to increase. It could even cause stomach problems, and you’ll find that you lack focus.

When should I drink pre-workout?

You should drink your pre-workout about 15 minutes before you start your exercise routine (you can read our article on building a workout routine here). Some people absorb the nutrients faster or slower which means you may need to experiment with this a little.

Is pre-workout bad for your kidneys?

No, generally speaking, pre-workout is not bad for your kidneys if you follow the recommended dosage. But, if you continue taking an excessive amount after suffering side effects, it could be bad, although kidney failure is not likely. Some of the ingredients could cause your blood pressure to rise and also cause dehydration which may have a negative impact on your kidneys with continuous high doses.

Can pre-workouts cause heart palpitations?

Yes, pre-workouts can cause heart palpitations if you already have a heart problem and take large doses of the supplement. If not, there is no need to worry. Your heart rate and blood pressure will rise due to the creatine and caffeine, but by just taking the recommended amount there shouldn’t be any problem.

Does pre-workout make you gain weight?

Yes, pre-workout can make you gain weight, but you won’t need to worry about getting fat. The build-up of new muscle tissue, which weighs more than fat, is the cause of an increase in your body weight. Rather than - looking at what your scales tell you, check out your BMI instead.

How long do the effects of pre-workout last?

The effects of pre-workout last between 1 to 2.5 hours on average, dependent on the dose you take and the concentration of the ingredients. Your metabolism and how hard you train will also have an impact, but for most people, this is long enough to cover a training session.

Can pre-workout cause or worsen depression?

No, generally pre-workout doesn’t cause or worsen depression, but you have to be careful with some ingredients. As long as you don’t buy a product containing artificial sweeteners such as Dimethylamylamine (DMAA) or Aspartame, there should be no problem. These ingredients really should be avoided if you have any mental health issues, but other than that there is no proof that pre-workout causes depression or worsens it.

Should You Take Pre-Workouts? The Bottom Line

So you’re now probably thinking “Should I take pre-workout supplements or shouldn’t I?"

The answer to this question is easy. Take them, but monitor any side effects and take immediate action if you notice any.

Believe it or not, they really do work, and high-performance athletes rely on them heavily. Just be sure to check out the various ingredients to ensure that you don’t have an intolerance to any of them.

These products provide so many benefits and as long as you only take the recommended dosage and buy a high-quality product very few downsides. We have a dedicated section on this site to help you find the best possible vegan pre-workout products available.

We also recommend checking out the 4-Gauge Pre-Workout Supplement as our top recommendation for you.

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  1. Uniformed Services University, PROPRIETARY BLENDS: WHAT DOES THIS MEAN?, retrieved from https://www.opss.org/article/proprietary-blends-what-does-mean
  2. Tia Ghose, Senior Writer, The Truth about Pre-Workout Supplements, retrieved from https://www.livescience.com/53095-do-preworkout-supplements-work.html
  3. Wilcox AR., The effects of caffeine and exercise on body weight, fat-pad weight, and fat-cell size., retrieved from https://www.ncbi.nlm.nih.gov/pubmed/7132651
  4. Michael J Breus Ph.D., What You Need to Know About L-theanine, retrieved from https://www.psychologytoday.com/intl/blog/sleep-newzzz/201708/what-you-need-know-about-l-theanine
  5. Rosemary A Fricker, Emma L Green, Stuart I Jenkins, and Síle M Griffin, The Influence of Nicotinamide on Health and Disease in the Central Nervous System, retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5966847/

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1 thought on “Pre Workout Side Effects
Are They Worth the Trouble?

  1. My buddies and I were debating about pre workout side effects because some of them experience headaches, high blood pressure, and more. Maybe not all supplements are for everyone I should say.

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