Does caffeine affect muscle growth?

does caffeine affect muscle growth

Caffeine is by far one of the most used drugs globally, but most people use it for its stimulatory effects. Not many people know that caffeine can increase muscle growth or that its muscle-building benefits are well documented in numerous research studies. In this article, we will try to answer the question does caffeine affect muscle growth?

What is Caffeine?

 The chemical name for caffeine is 1,3,7 trimethylxanthine. Caffeine is a naturally occurring substance found in the leaves, seeds or fruit of more than 60 different plants. Caffeine is a stimulant, meaning that it stimulates the brain. It also increases the circulation of chemicals and hormones such as cortisol and adrenaline. In small quantities, caffeine can give you a feeling of refreshment and focus. In large amounts, caffeine can make you feel anxious and have difficulty sleeping. [1]

Caffeine works by binding to adenosine receptors in the central nervous system, inhibiting adenosine binding. This binding on adenosine receptors inhibits the adenosine-mediated downregulation of the central nervous system activity.[2] By inhibiting the downregulation or “calming down” of the central nervous system, caffeine essentially stimulates it. This stimulation causes the elevation of energy, concentration and other beneficial effects.

Caffeine Molecule
Caffeine Molecule

How fast does caffeine work?

The stimulant effects of caffeine can be felt in as little as 15 minutes post oral administration. As with any other drug, the speed of caffeine absorption can vary widely and can be impacted by factors such as genetics, whether taken with food or on an empty stomach, if taken in pill form or as a liquid.

Caffeine is, on average, absorbed within about 45 minutes after consumption. Caffeine can peak in the blood anywhere from 15 minutes to 2 hours.[3]

How long does caffeine last?

The median half-life of caffeine is approximately 5 hours post-administration if taken orally. Caffeine remains in the blood between 1.5 and 9.5 hours.[4] Certain foods, nutrients, and drugs can delay caffeine absorption and peaks in the blood. For example, smoking speeds up the breakdown of caffeine, while birth control pills can slow the breakdown of caffeine. Foods high in fiber can slow the absorption of caffeine and thus slow the peak blood levels. The liver is the main organ responsible for caffeine breakdown and elimination, so chemicals, medications or diseases that impact liver function can also affect caffeine breakdown and elimination. 

What are the pros and cons of caffeine?

Caffeine is one of the most popular drugs on the planet, but often people forget that it is a drug and, as such, has benefits and risks or side effects. It is essential to understand both the positives and the negatives before you decide to take caffeine as part of your supplement regime.

Below is a list of the pros and cons of caffeine.


  • Helps muscle growth
  • Increases athletic performance
  • Increase weight loss
  • Decrease appetite
  • Decreases perception of effort
  • Stimulant
  • Increases alertness
  • Increases concentration
  • Diuretic properties


  • Negatively impact sleep
  • Increase anxiety
  • Elevate blood pressure
  • Increases sodium retention
  • Restlessness
  • Diuretic properties
  • Contraindicated with certain health conditions
  • Elevates heart rate
  • Increases cortisol

There are many more pros and cons, but these are the main ones that most people would be impacted by. Before even contemplating taking caffeine, you should consult your doctor to ensure that it is safe for you to do so.

Does caffeine affect muscle growth?

Caffeine has been shown to cause an increase in muscle growth compared to those who do not consume it. The primary source of caffeine consumption is via coffee, and this is where most researchers have focused their attention to see if caffeine has any muscle-building benefits. One study done by researchers at Harvard University showed that coffee drinkers could increase their testosterone levels while at the same time lowering their estrogen levels.[5] Testosterone is the primary anabolic hormone responsible for muscle growth and size, and if you can raise it, you will also increase your lean muscle mass. The increased testosterone was seen with as little as one cup of caffeinated coffee per day, and the most significant rise in testosterone levels was seen with 4 or more cups per day.

Another study done using rugby players showed that those given 800mg of caffeine before training showed an increase in testosterone of 21 percent compared to the placebo group, whose testosterone levels rose 15 percent.[6]

Increase in Testosterone per cup of coffee
Increase in Testosterone per cup of coffee

Caffeine has also been shown to speed up muscle recovery post-workout. As we all know, if you can improve and speed up muscle recovery, you can workout more intensely and more often, resulting in significant gains in muscle mass. Coffee and caffeine can speed up muscle recovery when taken with carbohydrates and your post-workout meal of protein shake.[7][8]

Another exciting area of research being done with caffeine and coffee is surrounding Sarcopenia. Sarcopenia is the muscle atrophy and wasting condition that is seen with aging. Researchers in Japan did a study that showed that people aged between 45 and 75 who consumed at least one cup of coffee per day had better grip strength and more skeletal muscle than those who did not drink coffee.[9]

Is too much caffeine bad for You?

Consuming too much caffeine can be dangerous and lead to mild side effects such as anxiety, insomnia, stomach upset, headaches, shakes, and jitters. In severe cases of caffeine toxicity, death can even occur. [10]How someone reacts to caffeine depends on a person’s age, weight, gender, and caffeine sensitivity. Genetic differences play a role in the tolerance and response to caffeine. People who consume caffeine regularly, such as drinking coffee every day, may develop tolerance to caffeine, which may reduce their side effects over time.

The real danger of consuming too much caffeine comes from the fact that it is in so many food products that we consume daily, and many people are unaware that they are consuming caffeine. The other risk factor is that caffeine is absorbed so rapidly. By the time you realize you have consumed too much caffeine, it is too late to do anything about it. As we mentioned above, the effects of caffeine can last for up to 9.5 hours.

How much caffeine is too much?

Based on the available research, 400 mg of caffeine per day is the safe level of caffeine that you can consume.[11][12] The important caveat to this number is that it will vary widely from person to person. As we mentioned above, age, sex, health status, and many more factors can impact caffeine absorption and tolerance. Each person needs to find a healthy amount that works for them and their lifestyle, with consultation with their doctor. 

So can caffeine impact muscle growth?

As you can see from the information we presented in the article, caffeine is a potent drug and can positively impact muscle growth. The studies provide some pretty interesting and compelling reasons why you should add caffeine to your supplement and muscle-building regime.

The information within this article is not to be taken as health or medical advice. For medical and health advice please always consult your doctor.