How much caffeine should you take before a workout?

Kelsey Brown, BSc


June 8, 2022

The most recent trait release focused on the effects of caffeine and how this supplement can be beneficial for muscle building.

My personal result told me that I am an increased responder with high sensitivity. This means that I am more likely to feel the stimulating effects of caffeine quicker than others, but with high intake, I am more likely to experience undesired effects such as anxiety and insomnia.

I wanted to explore what the most effective caffeine intake for myself would be, so here’s what I found out.

The muscle-building benefits of caffeine

Caffeine is one of the most popular ergogenic aids, which can be found naturally in the fruit, leaves and beans of coffee, cacao, and guarana plants. It is also one of the most studied supplements, there is a vast amount of evidence supporting the use of caffeine for enhanced physical performance.

Consuming caffeine can help improve alertness and reaction time and reduce perceived exertion rate, which helps delay feelings of fatigue and allows you to workout for longer periods. This can be useful when you are looking to increase muscle mass, as caffeine can allow you to complete more sets during a workout and at a greater intensity, helping to stimulate the necessary muscle breakdown for subsequent growth.

Getting adequate sleep is an important factor in building muscle and strength as this is the time when our muscles recover and adapt. However, over-consuming caffeine or using it late into the day can have a detrimental effect on both your sleep quality and duration, which carries consequences for your workout recovery and overall muscle growth. The amount of caffeine you consume, as well as the time that you consume it, is therefore a necessary consideration if you are looking to maximise your muscle-building results.

Caffeine response and genetics

While caffeine is considered to be beneficial for exercise performance, not everyone responds to it in the same way. For instance, your CYP12A gene can indicate whether you are a fast or slow metaboliser of caffeine.

Fast metabolisers are those who break down caffeine quickly after consumption and are likely to feel its effects sooner, while slow metabolisers are likely to experience its effects later but also for a slightly prolonged period. Gaining this insight can help to inform the ideal timing of your caffeine consumption, whether it’s to enhance exercise performance or to minimise your risk of sleep disturbance.

A second gene which is responsible for the differences in how we individually respond to caffeine is the ADORA2A gene, which is associated with caffeine sensitivity. Carriers of the ADORA2A TT genotype have been found to have a higher sensitivity to caffeine and are more likely to experience negative effects with caffeine intake, such as anxiety and insomnia. As a result, carriers of this genotype may need to be more mindful of how much caffeine they consume before workouts and throughout the day.

Recommended caffeine intake for exercise

The recommended intake of caffeine to support exercise performance and muscle building varies depending on caffeine sensitivity. For those with high caffeine sensitivity, FitnessGenes recommend that they limit their pre-workout caffeine intake to 1.5-3 mg per kg of bodyweight. For those with normal caffeine sensitivity, this recommended dosage increases to 3-6 mg per kg of bodyweight.

For example, an individual who weighs 75 kg and has a high sensitivity to caffeine would be recommended to take between 112.5 mg and 225 mg before a workout to maximise its performance benefits without increasing their risk of insomnia or anxiety.

For an individual of the same weight with normal sensitivity to caffeine, this recommendation would be increased to between 225 mg and 450 mg of caffeine before a workout.

Sources of caffeine

To place this in context, I’ve calculated my personal recommended caffeine intake and identified the sources I could use to reach this.

As a female of 62 kg with a high sensitivity to caffeine, my recommended pre-workout caffeine intake ranges from 93 mg to 186 mg.

There are a few different ways that I could get my caffeine intake before my workout. An 8-ounce mug of black coffee can contain around 95 mg of caffeine, so just two of these would put me towards the higher end of my recommended intake. A shot of espresso contains around 63 mg, so a double shot would put me in the middle of the bracket without consuming as much liquid as two mugs of coffee.

If you don’t like the taste of coffee, you may wish to try an energy drink to get some caffeine on board before exercise. Energy drinks differ in the amount of caffeine they contain, with Lucozade having just 46 mg per 380 ml bottle, Redbull having 80 mg in a 250ml can and Monster containing 160 mg in a normal can. However, these types of drinks can also contain high amounts of sugar, so that is something to take into consideration.

While drinking coffee or energy drinks can provide good quantities of caffeine, taking on that much liquid and sugar may not be desirable. There are gels and tablets which can provide a set amount of caffeine. For example, a Myprotein caffeine tablet contains 200 mg per tablet.

As benefits can be seen with lower amounts of caffeine, you don’t necessarily need to max out your recommended intake to obtain the full performance benefits. It is worth experimenting yourself and seeing if there is a difference in your performance after consuming different amounts of caffeine within your recommended range.

Discover your optimal caffeine intake

Ready to discover your optimal caffeine dosage, when you should take it, and when you should avoid it?

Become a FitnessGenes member by purchasing your DNA analysis or DNA upload product today to unlock Caffeine Responsivity and Building Muscle alongside 120+ more health and fitness-related traits

Kelsey Brown, BSc

Kelsey holds a BSc in Sport and Exercise Science (University of Winchester) and works as a part of the science team, carrying out research for trait and action creation and blog content. She plays netball for her local team and after enjoying learning her wedding dance so much has started Latin and Ballroom dance classes with her husband.

Start Unlocking Reports For Free

Create a FitnessGenes account to unlock your lifestyle-based reports for free, each with personalized insights and actions.
No credit card details required.

Get Started For Free