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Is Pre-Workout Bad For Your Brain? (Ingredients And Impact)

Michael Garrico
Published by Michael Garrico | Co-Founder & Marketing Director
Last updated: August 14, 2023
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There is no doubt that pre-workout can boost workout performance, but one of the common questions I get as a fitness professional is whether this popular supplement is bad for your brain.

To give my clients an accurate answer and hopefully put their minds at ease, I went over a few scientific studies on the subject and consulted our dietician about the common ingredients in pre-workout and their impact on the brain.

Read on to find out what I learned.

Quick Summary

  • A pre-workout supplement isn't bad for the brain, but it is linked to some side effects like headaches, and jitteriness.
  • Caffeine, L-citrulline, creatine, and nootropics are some of the ingredients found in pre-workout supplements.
  • Some people taking pre-workouts might experience insomnia, restlessness, and anxiety because of caffeine.

Is Pre-workout Bad for Your Brain?

A muscular person with a headache in the gym

Pre-workout is not bad for your brain, but it does come with some risk of side effects, including jitteriness and headaches.

Let’s examine this popular workout supplement a bit closer.


Let’s first look at the most common pre-workout ingredients and how they may affect the brain.


The most common ingredient in many pre-workout supplements is caffeine.

Caffeine is a central nervous system stimulant that most know improves energy and alertness, but it is also proven to enhance exercise performance [1].

Caffeine can improve many aspects of brain function [2].

These include:

  • Vigilance
  • Mood
  • Learning
  • Reaction Time
  • General cognitive function
  • Attention
  • Alertness

However, caffeine withdrawal symptoms might include headaches, and over the course of the abstinence crisis, it might actually cause the reverse of the aforementioned effects.


L-Citrulline is added to pre-workout to boost nitric oxide production and increase blood flow [3]. This increased blood flow helps hard-working muscles during a workout to get you better pumps and benefits the brain in several ways [4].

Some of these include:

  • Increased energy
  • Increased oxygen
  • Improved mental clarity
  • Boosted memory
  • Increased cognitive capacity to think clearly and make decisions
  • Improved problem-solving skills


A person drinking pre-workout

When people think about creatine in pre-workout supplements, they understand its benefit to muscle growth and recovery.

Additionally, many studies suggest that creatine benefits cognitive function [5].

More research shows that creatine supplementation of 5-20 grams daily may improve healthy adults’ short-term memory and reasoning ability [6].


Many popular pre-workout supplements contain nootropics, also known as cognitive enhancers or “smart drugs”.

In pre-workout, they are not drugs but natural ingredients that improve cognitive function [7].

Nootropics can enhance brain function in the following ways:

  • Increase focus and clarity
  • Increase motivation to perform tasks
  • Improve understanding
  • Boost memory and knowledge retention
  • Reduce mental fatigue
  • Reduce boredom
  • Improve brain health
  • Improve mental acuity
  • Improve reaction time
  • Heighten mood
  • Boost creativity

Examples of nootropics in pre-workout include:

  • L-theanine
  • Creatine
  • Rhodiola Rosea
  • Acetyl L-Carnitine
  • L-Tyrosine
  • Vitamin B12
  • Caffeine

“L-theanine is an amino acid found in tea that can increase feelings of calmness and may be linked to increased creativity. Its effectiveness is even greater when combined with caffeine.”

- Erica Julson, MS, RDN


A person holding a bottle of pre-workout

The most common practice is taking a pre-workout supplement before exercise to enhance athletic performance and increase stamina and energy.

Additionally, pre-workout can improve focus for studying, increase mental function for work or school, or increase mental energy for a late-night cram session.

Side Effects

Most side effects from pre-workout supplements come from the stimulants they contain.

These include:

  • Jitteriness
  • Anxiety
  • Headaches
  • Insomnia
  • Restlessness
  • Drowsiness

How to Safely Use It

A muscular person drinking from a bottle

For most people, pre-workout supplements are safe.

It is always best to consult your doctor before using any supplement, including pre-workout, to discuss any underlying medical conditions or medication interactions.

Also, to minimize potential adverse effects, do not take a higher dose than the manufacturer suggests.

If you are sensitive to stimulants, you can cut the dose in half to see if that helps with any side effects.


Does Pre-workout Mess With Your Head?

Pre-workout can mess with your head, likely due to stimulants. Caffeine is the most common stimulant in pre-workout supplements that can cause anxiety, restlessness, and insomnia.

Headaches are another side effect of stimulants and citrulline, another common pre-workout ingredient.

Does Pre-workout Affect Serotonin?

Pre-workout can affect serotonin which helps regulate behavior and attention. If pre-workout contains caffeine, it increases the serotonin neurons in the brain leading to improved mood and energy levels [8].

So, Is Pre-workout Really Bad for Your Brain?

My research suggests that pre-workout supplements themselves are not harmful to your brain, but some ingredients may cause adverse effects like headaches or anxiety.

Since there is no shortage of pre-workout options, we research and test many products here at Total Shape to make finding the right one easier for our clients.

Check out our lists of best pre-workout supplements here:

Top picks on our lists proved to be reliably effective with many of our clients without causing any of the commonly reported side effects.


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