Few supplements generate as many questions as creatine. It is mainly associated with gyms and bodybuilding, but in reality it is one of the most studied substances in sports nutrition, with decades of research into how it works and its possible applications.
Moreover, it is not a substance foreign to our bodies: the body produces creatine naturally, and we can also obtain it through certain foods.
In this guide, we explain what creatine is, what it is used for, and how it works, reviewing the available evidence and debunking some of the most common myths.
What exactly is creatine?
Creatine is a nitrogenous compound that the body naturally produces from three amino acids: arginine, glycine, and methionine. The kidneys and liver are primarily involved in this process.
We also obtain creatine through our diet, especially from animal-based foods such as meat and fish. People who follow vegetarian or vegan diets generally have lower muscle stores on average, since their diets provide much smaller amounts of creatine.
Approximately 95% of the body’s creatine is stored in skeletal muscle, both in free form and as phosphocreatine. The remaining percentage is distributed among other tissues with high energy demands, including the brain.
An adult can store approximately 120 to 140 grams of creatine, although this amount varies depending on body size, muscle mass, diet, and other individual factors.
Each day, a small portion of these stores is converted into creatinine and naturally eliminated through the urine. This is why the body continuously carries out a process of synthesis, use, and renewal.
Creatine is not a recent discovery
Creatine was first identified in 1832 while studying the components found in meat. Its name comes from the Greek term kreas, which means precisely “meat.”
Throughout the twentieth century, its role in energy metabolism—and especially in the rapid availability of energy for muscle—became better understood.
Its popularity as a sports supplement increased during the 1990s, at the same time that research into its use by athletes and physically active people was growing.
This long history explains why creatine has a much more extensive scientific track record than other ingredients recently introduced to the supplement market.
How does creatine work in the body?
To understand how creatine works, we first need to know about ATP, or adenosine triphosphate.
ATP acts as an immediate source of energy for cells. Muscles use it, among other functions, to contract during exercise. However, available stores are limited and are rapidly depleted during high-intensity exertion.
When ATP releases energy, it becomes ADP. At this point, phosphocreatine comes into play: it can donate a phosphate group to ADP to help regenerate ATP.
This process is part of the ATP-phosphocreatine system, or phosphagen system, which is particularly relevant during very intense, short-duration activities such as:
- A sprint.
- A jump.
- A heavy lift.
- A demanding set of squats.
- An explosive action during a team sport.
Creatine supplementation increases total creatine and phosphocreatine stores in the muscles above the levels obtained through diet alone.
In this way, the muscle has a larger reserve available to regenerate ATP during successive sets of brief, high-intensity exercises.
What is creatine used for?
Creatine’s main application is related to performance during brief, repeated, high-intensity efforts.
Scientific research has focused particularly on its effects in activities such as strength training, sprints, jumps, and sports that combine periods of maximum intensity with short recovery breaks.
Its main uses include:
- Performance during brief, high-intensity efforts.
- Strength training and muscular power.
- The ability to repeat sets or explosive actions.
- Increased muscle stores of creatine and phosphocreatine.
- Support for the rapid regeneration of ATP.
- Training aimed at developing muscle mass.
Creatine does not act as a stimulant and does not necessarily produce an immediate feeling of activation. Its effect is not like that of caffeine, nor does it depend on experiencing a “rush” before training.
Its use is mainly based on the progressive increase and maintenance of muscle stores.
Creatine and physical performance
The relationship between creatine and physical performance is one of the areas with the strongest scientific support.
The most consistent results are observed in exercises that require producing a high amount of force or power over short periods, especially when these efforts are repeated several times.
For this reason, creatine may be particularly interesting for:
- Weight training.
- Weightlifting.
- Powerlifting.
- Cross training.
- Track sprinting.
- Team sports.
- Disciplines involving jumps or accelerations.
- High-intensity interval sessions.
Its usefulness may be lower in exclusively aerobic, prolonged activities performed at a steady intensity, since other energy systems are primarily involved in them.
Creatine and strength training
The combination of creatine and strength training has been extensively researched.
During an intense set, immediate ATP stores decline rapidly. Phosphocreatine helps regenerate it, so having higher muscle stores may be useful when repeating high-intensity efforts.
Some studies have observed improvements in variables related to strength, power, and total training volume when supplementation is combined with appropriate planning.
Creatine does not build muscle automatically and does not replace training. Its possible contribution to muscle-mass development is related, among other factors, to the ability to sustain a greater training stimulus over time.
Consistency, nutrition, rest, and an exercise program adapted to each person remain essential for achieving results.
Creatine and recovery
The relationship between creatine and recovery has also been the subject of various studies.
The phosphocreatine system participates in the rapid regeneration of ATP, especially during rest periods between brief, intense efforts. For this reason, its influence on the ability to repeat sets and explosive actions has been studied.
Other studies have analyzed creatine supplementation in relation to markers of muscle damage, inflammation, and post-exercise recovery.
Results may vary depending on the type of training, the dose used, the duration of supplementation, and the characteristics of the participants. Therefore, this remains an active area of research.
Creatine and muscle hydration
When they begin taking creatine, some people notice a small increase in body weight. This has led to the myth that creatine “causes weight gain” or produces harmful fluid retention.
Creatine supplementation may increase the water content inside the muscle. This is mainly intracellular hydration, meaning water located inside the muscle cell.
This phenomenon is not equivalent to an increase in body fat. The extent of the change and its effect on weight may vary from person to person.
The relationship between creatine, body-water distribution, exercise in hot environments, and hydration status has also been investigated, without this meaning that it replaces proper fluid intake.
Creatine, the brain, and cognitive function
Although most of the body’s creatine is found in muscle, it is also present in the brain, where it participates in processes related to energy metabolism.
For this reason, there is a growing line of research on creatine and cognitive function.
Studies have explored its use in situations involving high cerebral energy demands, sleep deprivation, mental fatigue, aging, and diets with low creatine intake.
Some research has observed interesting results in certain tasks and population groups, while other studies have not found conclusive effects. The doses, contexts, and profiles of people for whom it may be most relevant are still being studied.
Therefore, this is a promising field of research, but the results are less consistent than those obtained in the area of brief, high-intensity exercise.
Creatine and aging
The relationship between creatine and aging has received increasing attention in recent years.
As time passes, changes may occur in muscle mass, strength, and the ability to perform certain activities. For this reason, different studies have analyzed creatine supplementation in older adults, especially when combined with resistance training.
Some studies have found favorable results in variables related to strength, lean mass, or functional capacity. However, results depend on factors such as age, initial fitness level, diet, and the training program applied.
Creatine does not replace strength exercise, but it continues to be studied as a possible supplement within strategies aimed at maintaining muscle function during aging.
Is creatine a steroid or a doping substance?
No. Creatine is neither a hormone nor an anabolic steroid.
It is a compound that our bodies produce naturally and that is also found in common foods such as meat and fish.
Nor is it included on the World Anti-Doping Agency’s list of prohibited substances.
Even so, athletes subject to testing should choose supplements that offer traceability guarantees and have undergone appropriate testing to reduce the risk of contamination with undeclared substances.
Who can take creatine?
Creatine is not used exclusively in bodybuilding or by professional athletes.
Taking creatine is common among adults who engage in strength training, high-intensity sports, or activities that include repeated explosive efforts.
It has also been studied in:
- Physically active people.
- Older adults who perform resistance training.
- Vegetarians or vegans.
- Individuals with low meat and fish intake.
- Athletes involved in strength, speed, and power sports.
- People interested in improving the quality of their training.
In cases of illness, pregnancy, breastfeeding, drug treatment, or any other clinical circumstance, it is advisable to consult a healthcare professional beforehand.
Food supplements should not be used as substitutes for a varied, balanced diet or a healthy lifestyle.
Differences between creatine and other supplements
Creatine may be confused with other common sports-nutrition products, but its function is different.
Creatine and protein
Creatine is not the same as protein.
Protein provides amino acids that the body uses to build and repair tissues. Creatine, on the other hand, is involved in the rapid ATP-regeneration system.
Therefore, creatine and protein perform different functions and should not be considered equivalent products.
Creatine and pre-workout
Pre-workout products may contain caffeine and other ingredients intended for use before physical activity.
Creatine is not a stimulant and does not necessarily produce an immediate feeling of energy. Its function is related to maintaining muscle stores, not to creating a temporary boost before training.
Creatine and BCAA
BCAAs are branched-chain amino acids. Creatine is neither a protein nor an amino acid, but a compound synthesized by the body from amino acids.
Both products have different characteristics and functions.
Creatine and fat burners
Creatine is not a fat burner. Its main function is not to speed up lipid metabolism or cause direct loss of adipose tissue.
Frequently asked questions about creatine
Is creatine the same as protein?
No. They are different compounds and perform different functions.
Protein provides amino acids, while creatine participates in the rapid ATP-regeneration system during intense, short-duration efforts.
Can you take creatine every day?
The most studied protocols use creatine every day to increase and maintain muscle stores.
A common maintenance regimen is around 3–5 grams per day, although the appropriate amount may depend on the product and individual circumstances.
The directions for use and the recommended dose on the food supplement should always be followed.
Is it necessary to take breaks?
Standard research protocols do not necessarily require alternating periods of use and rest.
Regularity helps maintain elevated muscle stores. Nevertheless, the product directions and individualized recommendations from a professional should be followed when necessary.
Does creatine cause weight gain?
Creatine does not, by itself, cause an increase in body fat.
Some people may notice an initial increase in weight related to a rise in body and muscle water content.
This change should not be confused with an increase in adipose tissue and may vary considerably between individuals.
How long does creatine take to work?
The time needed to increase muscle stores depends on the regimen used and each person’s initial levels.
With daily maintenance intake, the process is generally gradual and may take approximately three to four weeks.
Some protocols use an initial loading phase to accelerate the saturation of muscle stores. However, this phase is not essential to reach high levels in the long term.
When should you take creatine?
Daily consistency is generally more important than taking it at a specific time.
Creatine does not act as an immediate-effect stimulant. It can be taken at whatever time of day is most convenient and makes it easier to follow a regular regimen.
Do you have to take creatine before training?
It is not essential to take it immediately before exercise. Its function depends on increasing and maintaining muscle stores, not on an immediate effect associated with a single dose.
For this reason, it can be consumed before or after training, with a meal, or at another time of day.
Does everyone produce the same amount of creatine?
Not exactly. Synthesis and stores may vary depending on muscle mass, diet, and other individual factors.
People who consume little meat or fish generally obtain less creatine from their diet and may start with lower muscle stores.
Is creatine a food supplement or a medicine?
Creatine products intended to supplement the diet are marketed as food supplements, not medicines.
They are not intended to prevent, treat, or cure diseases and should be used according to the manufacturer’s directions.
What is the most studied form of creatine?
Creatine monohydrate is the most studied form and the one used in much of the available scientific literature.
Other forms of creatine are available on the market, but having a different name does not necessarily mean that they are more effective.
Choosing a high-quality creatine monohydrate should also take into account factors such as purity, composition, traceability, manufacturing process, and the testing carried out on the product.
Conclusion: what creatine is and what it is really used for
Creatine is a compound that the body naturally produces and that contributes to the rapid availability of energy for muscle.
Supplementation increases muscle stores of creatine and phosphocreatine, so its application is especially associated with performance during brief, repeated, high-intensity efforts.
In addition to its use in strength and power training, creatine continues to be studied in relation to recovery, aging, muscle hydration, and brain energy metabolism.
In these latter areas, results may depend on the population, dose, and context studied, so it is important to interpret the research rigorously.
Understanding what creatine is and what it is used for helps debunk myths and make informed decisions about its use.