Creatine is the number-one supplement for improving performance in the gym.

Studies show that it can increase muscle mass, strength and exercise performance (1, 2).

Additionally, it provides a number of other health benefits, such as protecting against neurological disease (3, 4, 5, 6).

Some people believe that creatine is unsafe and has many side effects, but these are not supported by evidence (7, 8).

In fact, it is one of the world’s most tested supplements and has an outstanding safety profile (1).

This article explains everything you need to know about creatine.

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Creatine is a substance that is found naturally in muscle cells. It helps your muscles produce energy during heavy lifting or high-intensity exercise.

Taking creatine as a supplement is very popular among athletes and bodybuilders in order to gain muscle, enhance strength and improve exercise performance (1).

Chemically speaking, it shares many similarities with amino acids. Your body can produce it from the amino acids glycine and arginine.

Several factors affect your body's creatine stores, including meat intake, exercise, amount of muscle mass and levels of hormones like testosterone and IGF-1 (9).

About 95% of your body's creatine is stored in muscles in the form of phosphocreatine. The other 5% is found in your brain, kidneys and liver (9).

When you supplement, you increase your stores of phosphocreatine. This is a form of stored energy in the cells, as it helps your body produce more of a high-energy molecule called ATP.

ATP is often called the body's energy currency. When you have more ATP, your body can perform better during exercise (9).

Creatine also alters several cellular processes that lead to increased muscle mass, strength and recovery (1, 2).

Summary Creatine is a substance found naturally in your body — particularly in muscle cells. It is commonly taken as a supplement.

Creatine can improve health and athletic performance in several ways.

In high-intensity exercise, its primary role is to increase the phosphocreatine stores in your muscles.

The additional stores can then be used to produce more ATP, which is the key energy source for heavy lifting and high-intensity exercise (10, 11).

Creatine also helps you gain muscle in the following ways:

  • Boosted workload: Enables more total work or volume in a single training session, which is a key factor in long-term muscle growth (12).
  • Improved cell signaling: Can increase satellite cell signaling, which aids muscle repair and new muscle growth (13).
  • Raised anabolic hormones: Studies note a rise in hormones, such as IGF-1, after taking creatine (14, 15, 16).
  • Increased cell hydration: Lifts water content within your muscle cells, which causes a cell volumization effect that may play a role in muscle growth (17, 18).
  • Reduced protein breakdown: May increase total muscle mass by reducing muscle breakdown (19).
  • Lower myostatin levels: Elevated levels of the protein myostatin can slow or totally inhibit new muscle growth. Supplementing with creatine can reduce these levels, increasing growth potential (20).

Creatine supplements also increase phosphocreatine stores in your brain, which may improve brain health and prevent neurological disease (3, 21, 22, 23, 24).

Summary Creatine gives your muscles more energy and leads to changes in cell function that increase muscle growth.

Creatine is effective for both short- and long-term muscle growth (25).

It assists many different people, including sedentary individuals, older adults and elite athletes (17, 25, 26, 27).

One 14-week study in older adults determined that adding creatine to a weight-training program significantly increased leg strength and muscle mass (27).

In a 12-week study in weightlifters, creatine increased muscle fiber growth 2–3 times more than training alone. The increase in total body mass also doubled alongside one-rep max for bench press, a common strength exercise (28).

A large review of the most popular supplements selected creatine as the single most beneficial supplement for adding muscle mass (1, 25).

Summary Supplementing with creatine can result in significant increases in muscle mass. This applies to both untrained individuals and elite athletes.

Creatine can also improve strength, power and high-intensity exercise performance.

In one review, adding creatine to a training program increased strength by 8%, weightlifting performance by 14% and bench press one-rep max by up to 43%, compared to training alone (29).

In well-trained strength athletes, 28 days of supplementing increased bike-sprinting performance by 15% and bench-press performance by 6% (30).

Creatine also helps maintain strength and training performance while increasing muscle mass during intense over-training (31).

These noticeable improvements are primarily caused by your body’s increased capacity to produce ATP.

Normally, ATP becomes depleted after 8–10 seconds of high-intensity activity. But because creatine supplements help you produce more ATP, you can maintain optimal performance for a few seconds longer (10, 11, 32, 33).

Summary Creatine is one of the best supplements for improving strength and high-intensity exercise performance. It works by increasing your capacity to produce ATP energy.

Just like your muscles, your brain stores phosphocreatine and requires plenty of ATP for optimal function (21, 22).

Supplementing may improve the following conditions (3, 24, 34, 35, 36, 37, 38, 39):

  • Alzheimer's disease
  • Parkinson's disease
  • Huntington's disease
  • Ischemic stroke
  • Epilepsy
  • Brain or spinal cord injuries
  • Motor neuron disease
  • Memory and brain function in older adults

Despite the potential benefits of creatine for treating neurological disease, most current research has been performed in animals.

However, one six-month study in children with traumatic brain injury observed a 70% reduction in fatigue and a 50% reduction in dizziness (40).

Human research suggests that creatine can also aid older adults, vegetarians and those at risk of neurological diseases (39, 41).

Vegetarians tend to have low creatine stores because they don't eat meat, which is the main natural dietary source.

In one study in vegetarians, supplementing caused a 50% improvement in a memory test and a 20% improvement in intelligence test scores (21).

Although it can benefit older adults and those with reduced stores, creatine exhibits no effect on brain function in healthy adults (42).

Summary Creatine may reduce symptoms and slow the progression of some neurological diseases, although more research in humans is needed.

Research also indicates that creatine may (5, 27, 43, 44, 45, 46, 47, 48):

However, more research in these areas is needed.

Summary Creatine may combat high blood sugar and fatty liver disease, as well as improve muscle function in older adults.

The most common and well-researched supplement form is called creatine monohydrate.

Many other forms are available, some of which are promoted as superior, though evidence to this effect is lacking (1, 7, 49).

Creatine monohydrate is very cheap and is supported by hundreds of studies. Until new research claims otherwise, it seems to be the best option.

Summary The best form of creatine you can take is called creatine monohydrate, which has been used and studied for decades.

Many people who supplement start with a loading phase, which leads to a rapid increase in muscle stores of creatine.

To load with creatine, take 20 grams per day for 5–7 days. This should be split into four 5-gram servings throughout the day (1).

Absorption may be slightly improved with a carb- or protein-based meal due to the related release of insulin (50).

Following the loading period, take 3–5 grams per day to maintain high levels within your muscles. As there is no benefit to cycling creatine, you can stick with this dosage for a long time.

If you choose not to do the loading phase, you can simply consume 3–5 grams per day. However, it may take 3–4 weeks to maximize your stores (1).

Since creatine pulls water into your muscle cells, it is advisable to take it with a glass of water and stay well hydrated throughout the day.

Summary To load with creatine, take 5 grams four times per day for 5–7 days. Then take 3–5 grams per day to maintain levels.

Creatine is one of the most well-researched supplements available, and studies lasting up to four years reveal no negative effects (8, 51).

One of the most comprehensive studies measured 52 blood markers and observed no adverse effects following 21 months of supplementing (8).

There is also no evidence that creatine harms the liver and kidneys in healthy people who take normal doses. That said, those with preexisting liver or kidney problems should consult with a doctor before supplementing (8, 51, 52).

Although people associate creatine with dehydration and cramps, research doesn’t support this link. In fact, studies suggest it can reduce cramps and dehydration during endurance exercise in high heat (53, 54).

Summary Creatine exhibits no harmful side effects. Though it’s commonly believed to cause dehydration and cramps, studies don’t support this.

At the end of the day, creatine is one of the cheapest, most effective and safest supplements you can take.

It supports quality of life in older adults, brain health and exercise performance. Vegetarians — who may not obtain enough creatine from their diet — and older adults may find supplementing particularly useful.

Creatine monohydrate is likely the best form. Try out creatine today to see if it works for you.