Creatine is one of the most popular sports nutrition products, and for good reason; it is one of the only legal ergogenic aids, has very few side effects, and boasts a plethora of benefits. 

In numerous studies, creatine has been shown to boost athletic performance, increase lean muscle mass, increase the storage of glycogen in muscle (aka, the stored carbohydrates used to fuel bouts of exercise), and can help prevent muscle loss in older adults when used alongside a resistance training program.

But what exactly is creatine and how does it work?

Creatine is a compound produced from amino acids. In the diet, creatine can be obtained from fish, meat, milk, and mollusks. The amount of creatine from food typically ranges from 1-2 grams per day when consuming an omnivore-style diet. The human body can also produce about 1 gram of creatine per day.

The majority of the body’s creatine (about 95%) is found in skeletal muscle, particularly in the fast-twitch muscle fibers associated with anaerobic exercise metabolism. Anaerobic exercise is anything that involves powerful, ballistic movement that is short in duration, yet high in intensity. Running or cycling sprints, heavy weight lifting, and box jumps are all examples of anaerobic activities.

In order to facilitate movement, muscle needs a compound called adenosine triphosphate, or ATP. The breakdown of ATP produces the energy required for movement, and the intensity of that movement will determine how the body obtains this energy.

Creatine acts as a substrate for ATP production via the phosphocreatine system. Muscle cells use creatine to make a compound called phosphocreatine (abbreviated as PCr), which is then used to convert adenosine diphosphate (ADP) to ATP during acute, high-intensity exercise lasting 10-20 seconds. Phosphocreatine donates a phosphate group to ADP, allowing it to convert to ATP, and therefore produce energy. While efficient, this process does not produce a large amount of ATP. If exercise continues for longer than 20 seconds, the body will switch to a metabolic process that yields a higher amount ATP, either through glycolysis or oxidative phosphorylation via the mitochondria. (Remember, the mitochondria is the powerhouse of the cell!)

Fatigue during high-intensity exercise can be linked to the hydrogen ions produced during exercise. Phosphocreatine can buffer these hydrogen ions, which reduces onset of fatigue and allows for longer bouts of anaerobic exercise. Supplementing with creatine can increase phosphocreatine concentrations by 10-40%.

Creatine’s Potential Mental Health Benefits

Additionally, newer research indicates that creatine may have mental health benefits. Some studies have found that phosphocreatine levels in the brain — which can be augmented with creatine supplementation — are linked to depression. 

Specifically, higher levels of phosphocreatine were associated with reduced symptoms of depression, as measured by depression rating scale scores.

How to Take Creatine, Side Effects, and Dosing

Creatine is typically found in a powder, but it can also be an ingredient in pre-workout supplementation mixes and drinks. On its own, a serving of creatine is usually 3-5 grams, depending on the manufacturer.

As mentioned, creatine has very few side effects. The most common complaints are water retention, dehydration, gastrointestinal upsets or diarrhea, and muscle cramping. These usually pass within a short period of time. Importantly, creatine is not on the list of banned substances put forth by the World Anti-Doping Agency, the International Olympic Committee, and the National Collegiate Athletic Association. Therefore, it can be used by athletes without concerns for safety or fear of disqualification.

Another perk of creatine is that the timing of the dose is not very specific. Studies have shown that, so long as creatine is taken consistently and around exercise (30-90 minutes before or after), an individual can reap the benefits of creatine supplementation. Creatine supplementation can begin with a loading regimen of 20-25 grams per day, in divided doses, for 5-7 days. 

This is done to quickly saturate the muscle’s creatine stores, and see the benefits of supplementation faster. However, this loading regimen is associated more directly with the side effects listed above. 

Some athletes may choose to only supplement with 3-5 grams per day; this usually results in less side effects, but benefits may not be seen for several weeks. 

Who Will Benefit from Creatine

It’s important to mention that not everyone will derive benefits from creatine. Within the context of sports performance, the general consensus is that strength and power athletes — such as weightlifters, sprinters, and even some team sport athletes like soccer players — see the most improvement in physique, athleticism, and recovery from creatine supplementation. 

Endurance athletes, such as runners, may not see much improvement due to the different metabolic processes the body uses in endurance sports. That said, a recreationally active individual, who may be strength training a few times a week and participating in cardiovascular sessions on a regular basis, could still notice changes in lean muscle mass.

More specifically, creatine could be used by individuals starting a strength training program, in order to maximize the adaptations to that style of training (i.e. increased muscle mass, better recovery between sets of exercise, etc). An athlete competing in a seasonal sport may find that creatine supplementation is most helpful when their strength training volume is the highest, wherever that happens to fall in their training plan.


Overall, creatine is a safe, effective supplement for athletes, recreationally active individuals, those looking to prevent the loss of muscle with aging, as well as those looking for potential mental health benefits by increasing levels of phosphocreatine in the brain. 

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Author: Maddie Hays, MSN, CN, Functional Medicine Nutritionist



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