Creatine is not a substance foreign to the body. Our body produces it daily from the amino acids arginine, glycine, and methionine in the liver and kidneys. We also obtain small amounts from our diet, mainly in the form of meat (raw beef 0.3–0.5 g/100 g). Cooking reduces the creatine content in meat.
In recent years, creatine has become the most widely used supplement, not only among athletes. As is often the case, several myths and frequent questions have arisen around creatine. So let’s clear things up once and for all.
Every athlete who takes their performance seriously will sooner or later face the question: “Which supplements are best for me—do I even need any?” One of the most well-proven supplements is creatine monohydrate.
The primary energy source for every muscle contraction is ATP (adenosine triphosphate). It acts as a universal fuel without which no movement is possible.
However, ATP stores in muscles are small and last only for the first few seconds of maximal exertion. Once ATP is depleted, cells must immediately regenerate it.
To continue at high intensity, the body uses the phosphocreatine system. Here’s how this energy conversion works: When a muscle contracts, an ATP molecule donates one phosphate group, releasing energy. The result is a “depleted” ADP molecule (adenosine diphosphate—having only 2 phosphates instead of 3). To avoid long delays, phosphocreatine stored in the muscles steps in. Phosphocreatine breaks down into creatine and a phosphate group, and this phosphate group is then transferred to ADP—recharging it back into ATP. This allows the muscle to continue at maximal intensity.
Long-term creatine supplementation increases your muscle phosphocreatine stores.
When you start taking creatine, you’ll likely notice one thing after a few days: the number on the scale jumps slightly upward. Many people panic at this point, thinking they’re gaining fat. The reality is quite different.
The initial weight gain when using creatine is mostly due to increased muscle hydration, not an increase in fat mass.
Early studies on creatine use—especially during the loading phase (about 20 g per day)—did show slight water retention in the first few days, but there’s a specific reason for this. Creatine is an osmotically active substance, meaning: creatine accumulates in the muscle cell and begins drawing water into the cell. This significantly supports cell hydration and increases cell volume.
Many athletes therefore worry they will look puffy or waterlogged. Longer-term studies show that creatine does not cause significant water accumulation outside the cells or lead to edema.
While classic water retention (e.g., due to hormonal changes or higher dietary sodium intake) is stored under the skin and creates a soft, puffy appearance, creatine works differently. If body water increases, it is predominantly intracellular water directly within the muscles. As a result, muscles appear fuller and firmer.
One of the biggest fears associated with creatine use is concern about kidney damage. Let’s examine this through scientific data.
Kidney damage from long-term supplementation at recommended daily doses has never been confirmed. So how did this belief arise? It all revolves around how kidney function is measured and how the body handles creatinine.
Every day, approximately 1–2% of the total creatine in muscles spontaneously converts to creatinine (a waste product of metabolism). Creatinine enters the blood, where it is filtered by the kidney glomeruli and then excreted in urine.
Serum creatinine concentration in the blood is commonly used as a clinical marker of glomerular filtration.
Why doesn’t higher creatinine necessarily mean kidney damage?
If you engage in strength training, have a higher proportion of muscle mass, or consume more meat, your blood creatinine level may naturally be slightly elevated. Lab results may therefore show higher values, but this does not automatically indicate impaired kidney function.
The entire concern about kidney damage most likely originated from individual case reports (single-patient case studies). An example might be the following study:
A scientific review led by Gualano et al. focused on similar case reports. It turned out that all cases were confounded (patients were taking immunosuppressants, had a history of kidney disease, took creatine in extreme doses, or even used anabolic steroids).
If you take creatine and your creatinine level comes back slightly above the reference range, there’s no need to panic. In case of unclear results, kidney function can also be assessed using other markers, such as cystatin C (a blood marker not influenced by muscle mass or creatine intake).
! In individuals with pre-existing, diagnosed kidney disease, any supplementation should be discussed with the treating physician in advance !
As our bodies age, we naturally lose muscle mass—a process called sarcopenia. This is associated with a higher risk of falls, fractures, and reduced independence. Great hope for preventing muscle loss lies in strength training and creatine.
Studies show that creatine alone does not significantly increase muscle strength or size. The short-term weight gain that sometimes occurs after taking creatine is due solely to water retention (creatine is osmotically active), not muscle growth. Long-term studies (e.g., in postmenopausal women) have confirmed that without exercise, creatine does not protect against muscle loss.
Creatine supplementation alone may slightly improve some parameters of muscle fatigue, but more is needed for actual growth and function.
However, when creatine supplementation is combined with regular strength training, the situation changes. Creatine can amplify the growth effect of exercise in both younger and older adults.
Thanks to creatine, training volume and intensity can increase, which positively affects muscle proteins, growth factors, and reduces inflammation and oxidative stress. The result is greater strength, better handling of daily activities, and delayed fatigue.
Research is also focusing on creatine’s effects on bone aging and osteoporosis:
According to research, creatine also has interesting effects on the brain. You’ll learn more about this in an upcoming article.
I have been working in the field of addiction counselling for more than 10 years. I hold a bachelor’s degree in Addictology from the First Faculty of Medicine and a degree in General Medicine from the Second Faculty of Medicine, Charles University. In my research, I focus on preventive medicine and epidemiology.
In my work with clients, I combine evidence-based knowledge with a holistic approach to mental health. My medical background enables me to understand the broader clinical context and to better support each client’s individual needs.
