What Is Pre-Workout? Is It Safe? A Detailed Guide

by on |

For enhancing athletic performance and recovery, many people turn to supplements. There is a huge range of supplements available to cater to every need and outcome. 

One of the most popular supplements is pre-workout. As the name suggests, this supplement is taken before a workout to enhance exercise performance.

In this article, we will go into depth about pre-workout supplements and review studies that have been conducted on these supplements.

What Is Pre-Workout?

Pre-workout tends to refer to a supplement in either powder, liquid, or pill form. It contains a number of stimulating substances with the intention of priming the body for exercise.

Commonly used substances include branch chain amino acids, beta-alanine, caffeine, creatine, and nitric oxide.

While there is a range of different products available, each product contains different combinations and quantities of each substance.

However, ultimately, the goal is the same: optimising energy production, athletic performance, and recovery.

Ingesting these stimulants causes physiological changes, including enhanced blood flow, increased energy production, reduced fatigue, and improved endurance.

How Does Pre-Workout Work?

The effects that pre-workout has on performance and recovery can be attributed to several substances.

The primary ingredient for the majority of pre-workouts is caffeine which is synonymous with improving energy and alertness.

In addition, caffeine has been shown to positively impact pain receptors, thus reducing the feelings of fatigue and promoting endurance (1).

Amino acids are also commonly used in pre-workout supplements to help to fight fatigue and promote exercise endurance.

Furthermore, these acids are well-known for the role they play in recovery. For example, amino acids are required to cause muscle protein synthesis to repair the muscles after training (2).

Other substances, such as nitric oxide, cause vasodilation to enhance blood flow to the muscles and the brain (3). This can lead to a substantial improvement in performance.

Although these substances appear to impact the physical primarily, they also have an impact on the brain. For example, stimulants can positively impact cognitive functions like focus and alertness.

Pre-Workout Benefits

This section will evaluate the benefits associated with pre-workouts by reviewing the research conducted on these supplements.

1. Boosts Energy Production

As highlighted, one of the primary purposes of taking pre-workout is to improve energy levels. Therefore, energizing the body will have a positive impact on how we perform.

Enhancing energy levels will allow exercise to be sustained at a high standard for a prolonged period of time.

Although several substances contribute towards increasing energy, caffeine and creatine have the greatest impact.

Caffeine is one of the most thoroughly studied drugs in science. Research categories caffeine as an ergogenic aid which means it can be used to enhance performance.

The drug acts on the nervous system and stimulates the brain, causing tiredness to reduce and alertness and focus on increasing (4).

Creatine is another well-studied substance that can often be found in pre-workout supplements. Unlike caffeine, creatine is naturally found within the cells of the body.

Creatine is essential for producing energy within muscle cells. Therefore, consuming creatine can enhance the amount of energy available and improve performance (5). 

2. Enhances Muscular Strength and Endurance

As well as enhancing energy, pre-workouts may improve muscular endurance. Once again, substances like creatine and caffeine have been found to cause endurance to increase.

A systematic review and meta-analysis on caffeine determined that caffeine can significantly improve strength and endurance (6).

Creatine also appears to be beneficial. Consuming creatine will allow the amount of energy produced to increase and consequently allow for heavier lifts and greater endurance (7).

Specific branch-chain amino acids such as arginine and citrulline may also improve endurance (8).

Combining heavier lifts and improved fatigue resistance will positively impact muscular strength, size, and athletic performance.

3. Increases Blood Flow

Vasodilation is the widening of blood vessels. This response can be triggered for various reasons, with one being the consumption of specific substances.

Once again, BCAA’s like arginine and citrulline have been found to cause vasodilation and consequently enhance blood flow (9).

While they do not directly cause vasodilation, they trigger the release of a compound known as nitric oxide. It is this compound that brings about the vasodilation response.

Vasodilation is of particular significance when it comes to exercise. Improving blood flow to the working muscles and the brain can substantially improve how we perform.

There must be a steady flow of blood during exercise to transport key nutrients, such as oxygen, the working muscles.

Furthermore, waste products, such as CO2, are produced during exercise and must be removed. Enhancing blood flow can facilitate the efficient removal of these waste products.

Therefore, pre-workouts may cause an increase in blood flow and consequently boost endurance and performance.

4. Enhances Mental Focus

Often, the importance of the mental side of training is overlooked. However, focus, alertness, motivation, and drive all significantly impact how well we train.

As highlighted, stimulants like caffeine onset a range of physical changes. However, they also bring about many mental changes.

Studies have indicated that stimulants act on the nervous system to boost alertness, attention, concentration, focus, and mood (10). 

Improving these cognitive functions can facilitate better physical performance and cause us to make significant progress with our training.

Furthermore, improving cognition may aid concentration levels and improve exercise safety and efficiency.

Pre-Workout Side Effects

A good quality pre-workout supplement can effectively improve performance. However, it should be noted that they may also cause certain side effects, including:

  • Diarrhea
  • Dehydration
  • Headaches
  • High Blood Pressure
  • Tingling
  • Insomnia

Common Active Ingredients In Pre-Workouts

As mentioned, the ingredients included in a pre-workout vary from product to product. This section will highlight four of the more common ingredients used in pre-workout supplements.

1. Caffeine

Caffeine is a drug that most people consume every day. Caffeine occurs naturally in several plant products, including coffee beans, cacao beans, and kola nuts.

Due to its powerful effects, caffeine tends to be the main ingredient contained within pre-workouts.

The substance has consistently been found to improve exercise performance. As highlighted, caffeine can positively impact fatigue, energy levels, and muscular performance.

2. Nitric Oxide

Studies into nitric oxide have yielded very positive results. It appears that increasing levels of nitric oxide in the body enhances blood flow and energy metabolism.

This makes it valuable for those who are looking to enhance their exercise performance. These changes may enhance fatigue resistance, athletic performance, and muscle recovery.

Many pre-workouts contain specific substances, such as arginine and citrulline, that can cause an increase in nitric oxide levels.

3. Creatine

Research on creatine supplementation has highlighted that it can significantly improve muscular strength and endurance.

Creatine is needed for energy production within the muscles. Therefore, by saturating the muscles with creatine, more energy can be produced. 

Increasing energy levels will allow us to produce the power required to lift heavyweight. In addition, more energy also means that exercise can be maintained for a longer duration.

4. Beta-alanine

Beta-alanine is an amino acid that appears to be beneficial for enhancing exercise performance.

Studies on the acid have suggested that supplementation of beta-alanine significantly reduces fatigue. This allows us to exercise at a greater intensity for an extended time period (11).

While beta-alanine is effective, it may cause the tingling sensation that is often experienced with pre-workouts.

Considerations Before Taking Pre-Workouts

1. Dosage

Due to the vast number of pre-workout supplements available, dosages vary from product to product. The quantity of specific ingredients will determine how much should be taken.

It is crucial that the recommended doses found on the product adhere to. Exceeding the recommended doses may increase side effects and adversely impact performance.

A doctor must be consulted before taking any pre-workouts. Many highly stimulating compounds within pre-workout may not be suitable for all. 

2. When To Take It

Some individuals will take pre-workout immediately before stepping into the gym. However, this is not optimal if we are looking to maximize the benefits of taking pre-workout.

Most of the ingredients contained within pre-workout do not take full effect instantly. It takes some time for the active ingredients to reach peak levels in the blood.

Therefore, it is recommended that pre-workout should be taken thirty to sixty minutes before exercise.

3. Cycling Pre-Workout

After taking pre-workout for a period of time, the body may adapt and become accustomed to it. As a result, the effects that are experienced may not be as powerful. 

Therefore, it may be worthwhile cycling pre-workout. This is where the supplement is taken for a prolonged period of time and then ceased for a short time.

Cycling pre-workout will allow the body to recover and may improve its sensitivity to pre-workout ingredients.

4. Sleeping Pattern

As reflected on, pre-workouts highly stimulate the nervous system, enhancing alertness and reducing tiredness.

Consequently, pre-workouts have the potential to disrupt sleep and make it more challenging to fall asleep. As a result, it may not be wise to take pre-workout in the evening.

Many believe that taking pre-workout during the day will not affect sleep. However, some stimulants stay in the bloodstream for a long time and, therefore, may still disrupt sleep (12).

5. Proprietary Blends

Proprietary blend supplements are products that list each ingredient but do not specify the quantities. Many manufacturers use these blends to hide their formulas from competitors.

The issue with this is that some manufacturers take advantage of this and add small key ingredients.  This allows them to advertise while cutting costs effectively.

The small quantities that are used often fall short of the optimal quantities determined by scientific studies. Therefore, these products may be ineffective for enhancing performance.


Is pre-workout bad for the body?

Providing that a high-quality supplement is chosen and the dosage instructions are adhered to, pre-workouts are safe.

There are some potential side effects associated with pre-workout. However, these are not severe and will pass as the effects of the pre-workout wear off.

That said, for certain populations, it may not be safe to take pre-workout. For example, those with medical conditions must consult a doctor before taking any pre-workout supplement.

What is in pre-workout that causes itching?

A popular pre-workout ingredient is beta-alanine. This amino acid has been found to reduce fatigue and enhance athletic performance significantly.

However, it does appear to cause sensations of burning, itching and tingling. It is thought that the acid interacts with receptors found in skin neurons which causes these sensations.

While these feelings may be unpleasant, typically, they are not anything to be concerned about. 

How long does pre-workout last?

Typically, the effects of taking pre-workout will be felt for one to two hours; however, this depends on the quantities of key ingredients.

Supplements that contain a large quantity of stimulants may experience effects for a longer duration than those with small quantities.

However, because some stimulants stay in the system for a long time, residual effects may be felt for up to six hours.

What makes a good pre-workout?

Studies have indicated that certain ingredients, such as caffeine, creatine, and beta-alanine, significantly affect performance. 

Therefore, a pre-workout supplement must contain these well-researched substances in decent quantities.

Proprietary blends hide the quantities of each ingredient and may, therefore, be ineffective. Additionally, extremely stimulating pre-workouts may cause significant side effects.

Is it okay to take pre-workout supplements on an empty stomach?

While taking pre-workout on an empty stomach may improve absorption time, it may also increase side effects.

Therefore, always refer and adhere to the manufacturer’s consumption guidelines.

Is it bad to drink pre-workout and not workout?

The majority of pre-workout supplements are safe to consume. Therefore, taking pre-workout and not working out is unlikely to have any detrimental effects.

That said, taking pre-workout on non-training days is needless and of little benefit. Furthermore, the body’s sensitivity to pre-workout may reduce if it is taken every day.


The studies that have been conducted on pre-workouts indicates that it can serve as a useful ergogenic aid.

Research suggests that the supplements can increase energy production, improve muscle performance, boost blood flow, and sharpen mental focus.

Key ingredients such as caffeine, creatine, arginine, citrulline, and beta-alanine have been attributed to causing these changes.

While the vast majority of pre-workouts are safe to consume, some individuals may experience side effects. These include dehydration, hypertension, insomnia and tingling.

As with all supplements, it is recommended to consult a doctor before taking any pre-workout product.


  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5306327/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4985555/
  3. https://www.ncbi.nlm.nih.gov/pubmed/27974299
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6548757/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3407788/
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5839013/
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5469049/
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4974864/
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6683098/
  10. https://www.ncbi.nlm.nih.gov/books/NBK209050/
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3374095/
  12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3805807/

Leave a Comment