What Is Creatine, and Why Is It So Popular?

If you have spent any time in a gym or researched sports nutrition, you have almost certainly heard of creatine. It is one of the most thoroughly studied supplements available, and one of the few with a consistent body of evidence behind it. Here is what it is, how it works, and what the research says.

What is creatine?

Creatine is a compound your body makes from amino acids, mainly in the liver and kidneys. It is also found in foods such as red meat and fish. About 95% of the body’s creatine is stored in skeletal muscle, much of it as phosphocreatine.^[1]

Your body produces roughly 1–2 grams of creatine per day, and a diet that includes meat and fish provides about 1–2 grams more. At those levels, muscle creatine stores are typically only around 60–80% full, which is why supplementation can raise them further.^[1]

How does it work?

During short, intense efforts such as a heavy lift or a sprint, your muscles run on ATP, the body’s immediate energy source. ATP is used up within seconds, and phosphocreatine helps regenerate it quickly. Supplementing with creatine increases muscle creatine and phosphocreatine stores by roughly 10–40%, giving your muscles more capacity to sustain high-intensity work.*^[1]

What does the research show?

Creatine monohydrate has been studied for decades in athletes, older adults, and clinical populations. The International Society of Sports Nutrition considers it the most effective nutritional supplement available for increasing high-intensity exercise capacity and lean body mass during training.^[1] Research supports:

• Greater strength and power output during resistance training*
• Improved performance across repeated high-intensity efforts, such as sprints and intervals*
• Greater gains in lean body mass when combined with a training program*
• Support for recovery between demanding training sessions*

Is creatine safe?

In healthy people, creatine monohydrate taken at recommended doses has an extensive safety record. A 2021 review of common misconceptions found no evidence that it damages the kidneys in healthy individuals, causes dehydration or cramping, or leads to hair loss, and it is not an anabolic steroid.^[2]

Some people notice a small increase in body water during the first few days, particularly when using a loading phase. Longer training studies have not shown a lasting increase.^[2] As with any supplement, speak with your healthcare provider before use if you are pregnant or nursing, under 18, taking medication, or have a medical condition.

Why creatine monohydrate?

Creatine monohydrate is the form used in the vast majority of published research. Other forms are often marketed as superior, but none has been shown to outperform it.^[1] It is well understood, effective, and affordable.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for general information and is not medical advice.