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Pre-Workout Side Effects

7 Pre-Workout Side Effects (& How To Avoid Them)

Pre-workouts are one of the most popular supplements on the market and the number of people taking them for workouts is growing each year.

They come in a range of forms including pills, shakes, and drinks and they contain different ingredients including caffeine, L-glutamine, and creatine, to name a few.

Pre-workouts are designed to give people a boost during their workout as they can increase energy levels, improve mental focus, and help to increase stamina.

However, whilst there are benefits to pre-workout supplements, many people are concerned about the potential side effects of these products.

Below, I’ve outlined 7 of the most asked about pre-workout side effects that can potentially be caused when using these supplements which include addiction, dependence on them to work out, building a tolerance, making you sick, itching, jitters, and insomnia.

I’ve also explained the different things that can be done to avoid these side effects so that you can get the most out of your workout without worrying about side effects.

Pre-Workout Side Effects

Most supplements will have some side effects and these will either be direct and known side effects – in which case they will be clearly displayed on the packaging – or they will be side effects as a result of an individual reaction or from taking the wrong dosage. 

It’s a rare occurrence but people have died from miss-taking or overdosing on pre-workout so it’s always important to check out the recommended manufacturer dosage and side effects before taking any pre-workout supplement. 

For pre-workouts, there are a number of common side effects which include:

  • Addiction
  • A dependence on pre-workout when exercising
  • Become tolerant to the ingredients
  • Sickness
  • Itching 
  • Jittery
  • Insomnia or difficulty sleeping

Below, we’ll look into each one of these common side effects in a bit more detail.

1) Addiction

One potential side effect of pre-workout is addiction. In general, pre-workout products don’t contain ingredients that would cause addiction. However, there is an exception to this: caffeine.

Caffeine is a kind of stimulant. It’s often used in pre-workout products because it provides a big boost in energy levels and can increase mental focus – both of which people want when they’re about to workout.

The levels of caffeine in pre-workout products are often high. 

For example, the average cup of coffee will contain about 40mg of caffeine, whereas pre-workout products can have doses of 400mg and more!

Related – Coffee vs pre-workout (compared)

The downside of this is that caffeine contains addictive properties that can cause a kind of physical dependence.

This can be a problem as caffeine addiction can cause people to continually crave caffeine.

Being physically dependent on caffeine can also cause issues when people try to stop. 

As people become used to caffeine, they can experience withdrawal symptoms such as headaches and difficulty concentrating, when they don’t have caffeine.

To avoid becoming addicted to pre-workout then, it’s important to monitor and reduce caffeine consumption.

Caffeine addiction can be caused by regularly consuming pre-workout products that contain caffeine. 

By limiting the frequency of pre-workout use it’s less likely that people would become dependent on the caffeine it contains, as it’s not something that’s being regularly consumed.

This can mean cutting back on the number of times per week that pre-workout supplements are used. Using these products sparingly will help to prevent developing a caffeine addiction.

Another option is to go without caffeine. As caffeine is the potentially addictive ingredient, then it makes sense to look for alternatives.

The good news is that there are a range of caffeine free pre-workout products on the market so finding one without caffeine shouldn’t be a problem.

2) Dependence On Them To Workout

As I’ve mentioned, the ingredients in pre-workout products generally aren’t addictive with the exception of caffeine.

However, even though the ingredients aren’t addictive, some people can become dependent on pre-workout to workout.

This is because pre-workout can make people feel good by giving them a big boost in energy which can allow them to maximize their workout.

At times, people may feel like they can’t workout without taking pre-workout first, or they may feel like they need to take pre-workout on days when they aren’t working out.

This kind of dependence usually happens when people regularly use pre-workout products, as they may not workout without them for a while and then struggle to workout without them anymore.

Pre-workout products aren’t supposed to be used all the time, so this kind of dependence should be avoided. 

I’ve never personally felt the full effects or pre-workout so don’t tend to take any buy some people take pre-workout everyday (even when not training) or have to have pre-workout before every single workout

To avoid becoming dependent on pre-workout, it’s important to use them sparingly. 

Reserving pre-workouts for intense workouts and not consuming them often means that people will have to workout without them most of the time.

This way they don’t build up a kind of dependence or reliance on them to workout.

3) Build A Tolerance

Another key issue when it comes to pre-workout products is building up a tolerance.

A tolerance happens when people become used to the ingredients within a pre-workout product. 

Essentially, over time the cells within the body can become desensitized to certain things. This means that these ingredients are no longer felt in the same way anymore.

This usually happens through repeated exposure to stimulants, such as caffeine, in pre-workout supplements. Although it can also happen with other ingredients too, such as beta alanine.

Many people will notice a decrease in the effectiveness of their pre-workout after around 4-6 weeks of consistent use. But tolerances do vary between individuals.

To avoid building up a tolerance to pre-workout it’s important to take breaks from ingredients. 

Different pre-workout products will come with different instructions for when to take a break, but generally it will be after around 4-8 weeks of use.

During this break, people can change to a different pre-workout product that contains different ingredients. This is known as product cycling. 

People can also take a complete break from pre-workout products and go without them.

Generally, product cycling or taking a break is done for a couple of weeks. During this time, people’s tolerance to the ingredients within pre-workout decreases.

This means that when they go back to using them they have their original kick again.

You could also look to use a non-stimulant pre-workout which contains some of the same energy/mental boosting ingredients as a regular pre-workout but without the stimulants that you can become dependent on (or tolerant to).

4) Make You Sick

Pre-workout supplements can make some people sick

This can include gastrointestinal and digestive issues like nausea, stomach ache, and diarrhea, but there are others too.

These kinds of side effects can be caused by different ingredients within pre-workout products, as well as the dosage of these ingredients.

For example, caffeine can cause higher levels of stomach acid, especially in people who already have sensitive stomachs. 

When stomach acid levels get high, they can irritate the lining of the stomach leading to things like nausea and stomach pains.

As caffeine is a stimulant, it can also trigger the digestive system. 

Basically, it can cause more contractions in the bowel, leading to diarrhea or a sudden need to go to the toilet which obviously isn’t ideal when you want to be working out!

This is a newbie mistake that you don’t want to be caught making! If you get carried away and take too much pre-workout, you can easily end up getting caught short in the gym. 

Thankfully this has never happened to me but I do know a few people personally who have had mid leg session diarrhea because of the amount of pre-workout they’ve taken so definitely be cautious when choosing a dosage.

Higher doses of ingredients like caffeine are going to play a bigger role in this as the more caffeine consumed the more of an effect it’s going to have.

Though I’ve focussed on side effects related to caffeine, these kinds of digestive symptoms can also be caused by sodium bicarbonate, magnesium, and creatine

When it comes to avoiding these kinds of side effects, it can be difficult as it’s hard to identify which ingredient is causing the problem.

Some people try a trial and error approach by using different pre-workouts containing different ingredients until they find one with ingredients that work for them.

Another approach is to try taking pre-workout with and without food. 

Some people find that these digestive symptoms can be helped by taking their pre-workout after eating. For example, if pre-workout causes excess stomach acid then eating before can help with this.

However, for other people the opposite is true. Some find that taking their pre-workout on an empty stomach helps to reduce digestive side effects.

As everybody’s different, it can be a case of trying it and seeing what works as there isn’t one solution for everybody.

5) Itchy 

Pre-workout can also make people itchy. This is caused by the ingredient ‘beta-alanine’, which is an amino acid that plays a role in muscle endurance during intense workouts. 

This is why it’s sometimes called the ‘beta-alanine itch’.

Though it should be noted that an allergic reaction can also cause itching. This is much more serious and you should get medical attention if you experience signs of an allergic reaction.

Side effects associated with beta-alanine include itching, tingling, pins and needles, as well as numbness in the skin. They’re usually experienced in the neck, arms, and shoulders and last for about 30-45 minutes once they have started.

This is thought to happen because beta-alanine can cause ‘acute paresthesia’ as beta-alanine affects the nerve endings in the skin.

Although pre-workout itching isn’t thought to be harmful, it can be distracting and uncomfortable during a workout so there are different things you can do to avoid it. 

Itching is usually caused by higher doses of beta-alanine of 2g or higher.

Therefore, splitting the dose of beta-alanine and taking smaller doses more frequently may stop pre-workout itching. 

Rather than taking one dose before a workout, taking a smaller dose before a workout and another at another time should reduce the skin sensations it causes.

Another option is to avoid pre-workout supplements containing beta-alanine completely. 

It can be hard to separate out and accurately weigh beta-alanine, especially if it’s within a mix containing other ingredients, so avoiding pre-workout containing beta-alanine entirely might be a better option.

There are plenty of pre-workout supplements on the market, so finding one that is beta-alanine free shouldn’t be an issue.

6) Jitters

Pre-workout products can also cause jitters. Jitters are a kind of shaky feeling involving the physical sensations people experience when they consume a lot of caffeine.

They happen because caffeine acts as a stimulant to the nervous system.

As I’ve mentioned, pre-workout products often contain high doses of caffeine, sometimes as high as 400mg and above. 

Considering the high dose of caffeine that can come in just one pre-workout supplement, it’s unsurprising that people can feel jittery afterwards!

This jittery feeling isn’t something you want. It can be distracting during a workout, and potentially dangerous if it causes hands to shake.

To avoid this jittery feeling, there are different things that can be done. The main one is to reduce caffeine consumption. As this feeling is caused by caffeine, reducing the amount should reduce its effects.

Whilst pre-workout products often contain high doses of caffeine, not all pre-workout products do. 

There are a variety of pre-workout products on the market today, so aim for one with a low caffeine dose to minimize any jitters.

However, people’s sensitivity to caffeine varies greatly. Some people will feel jittery even with low doses of caffeine. In this case, it can be best to completely avoid caffeinated pre-workout products.

Instead, go for a product that is caffeine free.

7) Insomnia

Another potential side effect of pre-workout is insomnia. 

Insomnia is a kind of sleep disturbance characterized by struggling to fall asleep, struggling to stay asleep, or not being able to sleep at all. 

Insomnia and other kinds of sleep disturbance can be caused by pre-workout because they contain caffeine – the caffeine content is a recurring theme throughout in case you’ve not noticed yet!

As I mentioned, caffeine is a stimulant. As it provides a big boost in energy, it can make it much harder to have a good night’s sleep.

This is a problem because sleep is crucial for our overall health and well-being. It also plays a significant part in muscle recovery and development, so sleeping poorly can undermine the gains seen from working out.

To avoid insomnia and sleep disturbance as a result of pre-workout there are different things that can be done.

One option is to get the timings right for taking pre-workout.

The effects of caffeine reduce over time as caffeine has a half life of about 5-6 hours. This means that about half the caffeine will have been metabolized within this time period. As a result, it’s effects shouldn’t be as strongly felt after this time.

In order to reduce the potential negative impact of pre-workout on sleep then, make sure it isn’t consumed within 5-6 hours of bedtime. 

Related – How long does pre-workout stay in your system

This way, the caffeine within pre-workout has already reduced in effectiveness by bedtime, which should reduce its impact on sleep.

This is also the reason we don’t recommend taking pre-workout at night

If you train in the evening, it may be best to avoid a pre-workout and just power through a session without it because a loss of sleep could be more detrimental to your progress than an “unstimulated” workout. 

With this being said though, as I mentioned earlier, people’s responses to pre-workout and their sensitivity to caffeine does vary. 

Unfortunately, some people will experience sleep disturbance regardless of what time they take their pre-workout as it’s just how their body responds to caffeine.

In this case, another option is to go for a pre-workout without caffeine. Due to the popularity of pre-workout there’s a huge range of low-caffeine and caffeine-free options to choose from.

How to Reduce Pre-workout Side Effects

To reduce pre-workout side effects, try to implement some of the following: 

  1. Only take the recommended dosage and take the minimum amount you need to still feel the maximum effects from it
  2. Don’t take pre-workout late at night. This will minimize the impact on your sleep
  3. Rotate pre-workout ingredients to minimize your tolerance to it
  4. Cycle pre-workout usage every 4-8 weeks to ensure you don’t become tolerant or dependent on pre-workout
  5. Test different ingredients and ingredient quantities to see what works best for you in terms of focus, energy, and pump in the gym without the crash or other side effects
  6. Try stimulant-free pre-workouts like nootropics to see if you respond better to this Stim-free pre-workouts won’t cause jitters, tingles, nausea, or other side effects associated with stimulants
  7. Stay hydrated. This is a huge one as dehydration will compound the side effects from pre-workout and in many cases could even be the root cause of the side effects that you feel


Please keep in mind this article is for informational purposes only and should not be taken as medical advice. Before taking supplements like pre-workout you should seek advice from your medical practitioner. 

If you do feel any harmful side effects from pre-workout supplementation then seek medical attention or advice immediately. 

If you’ve found this interesting then you might also want to see our article on what to do if you take too much pre-workout

The anxiety from taking too much pre-workout isn’t fun so it’s good to know how to avoid it or deal with it if you do get too carried away with the number of scoops…

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