Pre-Workout Side Effects (and How to Avoid Them)

Pre-workout side effects can be common, so we’ve put together a guide on how to deal with them and get the best out of your supplement.

Disclaimer time. We want to start this article by saying that, if not taken correctly, pre-workout can have side effects that may have a negative impact on your health. If you have any concerns at all about taking a pre-workout or suffer from any illnesses, you should consult your doctor first.

Sure, they can help you feel stronger, go further and generally feel more energized at the gym. However, we’d be lying if we’d said we’d never felt a side effect from a bad pre-workout.

Luckily for you girls, we’ve learnt from our pre-workout side effects and are here to bring you the science on how to avoid the unwanted extras.

Related Article: Check out our guide to the Best Pre-Workouts for Women in 2019

Woman struggling to sleep as part of a pre-workout side effect

 1. Insomnia

A lack of sleep can impact your life in so many ways. Your mood will be low, your energy levels through the floor and you’ll struggle to concentrate. No one likes to be tired and cranky, especially if you’re trying to slay the gym on the regular.

If you start to find it hard to sleep after taking your pre-workout, check out the label. The majority of pre-workout formulas contain a healthy helping of a stimulant to improve your energy and focus levels when you head to the gym. This is usually present in the form of caffeine.

Now, we don’t mean an extra espresso before a workout, some are pumped with up to 400mg of caffeine. That’s a huge portion girl.

Imagine if you’re drinking your normal three coffees throughout the day, then you hit a caffeine pumped pre-workout right before your evening session. That’s a recipe for sleepless nights and staring at the ceiling for hours on end.

A study found that caffeine can impact sleep up to 6 hours after it’s been ingested [1], so it’s definitely worth keeping it as far away from your bed time as possible.

How to avoid it

Everyone has a different sensitivity to caffeine and metabolizes it at different rates. However, chances are if you’re suffering from insomnia from your pre-workout, you might be on the sensitive side.

To help avoid sleepless nights, but still get the most out of your workout, don’t take your pre-workout any later than five hours before you go to bed. If you usually hit the sack at around 11pm, take the supplement no later than 6pm.

If you try that and it doesn’t work, you can either half your portion of pre-workout, or even look for another brand that has a smaller, more manageable serving of caffeine in the formula.

[Related Article: Caffeine Anhydrous Explained – What is it and How Does it Work? ]

Woman drinking water to avoid dehydration after a pre-workout

2. Dehydration

There are a number of elements in a pre-workout that could leave you dehydrated. They can make you feel stronger and more energized, but they can also cause you to become dehydrated if you don’t have adequate water in your body.

Caffeine is a diuretic, which will increase your need to pee and potentially lead to a lack of water in your system. As a lot of pre-workouts have quite a large helping of caffeine in them, this can happen quite easily.

A lot of pre-workouts also contain creatine which boosts muscle pumps and power as you work out. It does this by drawing more water into your muscles, which can also lead to dehydration if you don’t have enough H2O in your body.

On top of that, if you head to the gym you’ll be sweating, which will contribute to the dehydration, especially if there’s creatine in the mix.

How to avoid it

As a pre-workout side effect, dehydration can be handled pretty easily. The best way to combat it is, you guessed it – drink more water.

We’re not just talking about downing a few glasses before you head to the gym, you need to be sipping on water all day long. If you take your pre-workout and the diuretics start to take effect, or you’re working out real hard, be sure to replace any water lost and drink accordingly. By doing this, you’re priming your body with the optimum amount of water, then topping up your body whenever it’s needed.

[Related Article: A Definitive Guide to Pre-Workouts for Women]

Woman holding her head because she has a headache

3. Headaches

This can be another side effect of dehydration. When you’re completely hydrated, your brain is full of water. If you don’t have enough water in your system, it shrinks temporarily, which can lead to a painful headache. The pain you feel from this can vary depending on the severity of your dehydration and can even lead to migraines.

Muscle pump ingredients can also give you a headache if you’re particularly sensitive to them. L-citrulline, L-arginine and beta-alanine are commonly used in pre-workouts to increase vasodilation, so your muscles feel bigger and more powerful.

They can also cause the vessels in your brain to expand, which can then cause headaches.

How to avoid it

If you’re experiencing dehydration symptoms like fatigue, dizziness, dark urine and extreme thirst, then your headache may be caused by the lack of H2O in your body. To combat this, ensure you’re drinking enough water throughout the day and before and after you take your supplement.

If you’re not dehydrated and you’re still experiencing headaches, try reducing the amount of pre-workout you take, or look for a product without any vasodilating ingredients in the formula.


A woman bent over with her hands on her knees after a long run.

4. The runs

Sorry girls, but unfortunately this can be a pre-workout side effect.

Some ingredients can directly cause these issues in certain measurements. High dosages of magnesium, caffeine, arginine and creatine are key culprits, so check the serving sizes if you’re particularly sensitive to this kind of issue. Then maybe give it a test run before you knock back a shake in the middle of the gym.

Unfortunately, the supplement market is full of products that are thrown together rather than carefully created. That means that some supplement creators don’t recommend you take enough water with your pre-workout. You should aim to mix your supplement with a lot of water as, if you don’t have enough, you could end up with a paste in your stomach.

To absorb this paste, your body draws water into your stomach. Unfortunately, this can also mean water ends up in your intestines, causing diarrhea effects.

How to avoid it

If you find you’re particularly sensitive to the ingredients above, check the label of every pre-workout you buy.

However, it’s quite likely that you’re running to the toilet because of the way the creators recommend you take it. First, try taking the supplement with more water, then be sure to drink plenty after you’ve ingested it. That should help to reduce the risk of diarrhea.

This side-effect can also lead to further dehydration, so be sure to drink more water if you ever experience it.

A doctor holding a blood pressure monitor and measuring someones blood pressure

5. High blood pressure

Just about every pre-workout contains stimulants, for a good reason. They boost your energy levels and increase your focus, so you can get more out of your workout.

A recent study found that an average of 150-200mg of caffeine helped weightlifters to significantly improve their squat and bench press[2].

However, by their very nature, a stimulant like caffeine can increase your blood pressure. You may feel this more when you’re working out, as lifting weights or hitting cardio will also boost your heartrate.

This can be associated with feelings of anxiety or stress too, so if you experience these issues, or you have a blood pressure issue, always consult your doctor before you take a pre-workout.

How to avoid it

A lot of pre-workouts contain caffeine or similar stimulants, however there are a number of products available with a smaller dosage. If you’re worried about your blood pressure, do some research and find a pre-workout that has a much lower stimulant content, or that contains none at all.

Woman holding her hand to represent hand tingles

6. The tingles

You may occasionally feel tingling in your hands and feet when you take a pre-workout. This side effect is caused by the ingredient beta-alanine. It’s a common ingredient in these supplements and can be found in naturally in high-protein foods.

It’s a common addition to pre-workouts because it can help to boost muscular endurance during a workout. However, in doses above a gram or so, it can cause tingling or itching sensations in your hands and feet – this is called paresthesia.

It isn’t actually harmful to you in any way, but it can be annoying if you’re trying to smash a workout.

How to avoid it

If the tingles are too annoying for you to get the most out of your workout, a simple way of avoiding them is to avoid beta-alanine altogether, or lower your pre-workout dose so you’re taking on less than 1g of it.

The final scoop

Whether you’re already using one or scoping out the market, it’s always a great idea to be aware of any potential pre-workout side effects. A pre-workout has the power to help you go further and achieve more, but if they’re making you feel ill you won’t get the best out of them.

Once you know what these side effects are and how to minimize their impact on your body, you can start to really benefit from the pre-workout. Try out our helpful solutions now and maximize the effectiveness of your supplement.


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[1] Drake, C et al (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med. Nov 1195 – 1200.

[2] Del Coso, J et al (2012). Dose response effects of a caffeine-containing energy drink on muscle performance: a repeated measures design. Journal of the international Society of Sports Nutrition. May 9:21.


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