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).

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

In fact, it is one of the most studied supplements ever, and has an outstanding safety profile (1).

This detailed guide explains everything you need to know about creatine.

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. The body can produce it out of 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 the body's creatine is stored in muscles, in the form of phosphocreatine. The other 5% are stored in the 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).

Bottom Line: Creatine is a substance found naturally in your body, particularly muscle cells. It is commonly taken as a supplement.

There are several ways that creatine can improve health and athletic performance.

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 other ways, including:

  • Boost work load: It can enable more total work or volume in a single training session, which is a key factor in long-term muscle growth (12).
  • Improve cell signaling: Supplementation can increase satellite cell signaling, where signals to the muscles help with repair and new muscle growth (13).
  • Raise anabolic hormones: Studies have shown that there is a large rise in hormones, such as IGF-1, after supplementation (14, 15, 16).
  • Increase cell hydration: It is well known for increasing the water content within muscle cells. This causes a cell volumization effect that may play a role in muscle growth (17, 18).
  • Reduce protein breakdown: Supplementation may also help increase total muscle mass by reducing muscle breakdown (19).
  • Lower myostatin levels: Elevated levels of the protein myostatin are well known for slowing or totally inhibiting new muscle growth. Supplementing can reduce these levels, increasing growth potential (20).

Creatine supplements also increase phosphocreatine stores in the brain. This may improve brain health and protect from neurological disease (3, 21, 22, 23, 24).

Bottom Line: Creatine helps you gain muscle in several different ways. It gives your muscles more energy and leads to changes in cell function that increase muscle growth.

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

It has benefits for a variety of people, including sedentary individuals, the elderly and elite athletes (17, 25, 26, 27).

One 14-week study of the elderly found that adding creatine to a weight training program significantly increased leg strength and muscle mass (27).

A 12-week study in weight lifters found that the supplement increased muscle fiber growth two to three times more than training alone. The increase in total body mass also doubled, along with their bench press one-rep max (28).

A large comparison of the most popular supplements found creatine to be the single most beneficial supplement available for adding muscle mass (1, 25).

You can find a more detailed review of the effects on muscle growth in this article.

Bottom Line: Supplementing with creatine can lead to 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.

A research review found that adding it to a training program increased strength by 8%, weight lifting 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 supplementation increased bike sprinting performance by 15% and bench press performance by 6% (30).

It has also been tested during intense over-training blocks, shown to help maintain strength and training performance while increasing muscle mass (31).

These noticeable improvements are primarily caused by increased capacity to produce ATP.

Normally, ATP becomes depleted after 8-10 seconds of high-intensity activity. Supplementation helps you produce more ATP, allowing you to maintain optimal performance for a few seconds longer (10, 11, 32, 33).

Here are some more details on creatine's effects on exercise performance.

Bottom Line: 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.

One of the most exciting prospects has to do with brain health and the treatment of neurological diseases.

Like muscles, the brain stores phosphocreatine and requires plenty of ATP for optimal function (21, 22).

Supplementing has been suggested to improve the following conditions:

  • Alzheimer's disease (34).
  • Parkinson's disease (3).
  • Huntington's disease (24).
  • Ischemic stroke (35).
  • Epilepsy (36).
  • Brain or spinal cord injuries (37).
  • Motor neuron disease (38).
  • Memory and brain function in the elderly (39).

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

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

For general brain function, human research suggests that it can benefit the elderly, 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.

One study in vegetarians found that supplementing caused a 50% improvement in a memory test and a 20% improvement in intelligence test scores (21).

Although it can be beneficial for the elderly and those with reduced stores, research shows no effect on brain function in healthy adults (42).

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

Research has also shown that it may:

  • Lower blood sugar levels (5, 43, 44).
  • Improve muscle function and quality of life in the elderly (27, 45, 46, 47).
  • Help treat non-alcoholic fatty liver disease (48).

However, more research is definitely needed in these areas.

Bottom Line: Creatine may help with blood sugar control and fatty liver disease. It may also have various benefits for the elderly.

The most common and most researched form is called creatine monohydrate.

Then there are many other forms available, some of which are claimed to be superior. However, there is no evidence that the other forms are better (1, 7, 49).

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

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

Many people who supplement start with a "loading phase." This strategy leads to a rapid increase in muscle stores.

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 release of insulin (50).

Following the loading period, take 3–5 grams per day to maintain the elevated levels within the muscle. There is no benefit to cycling creatine, so you can stick with the 3-5 gram dose 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 three to four weeks to maximize muscle stores (1).

As creatine pulls water into the muscle cell, it is also advisable to take it with a glass of water and stay well hydrated throughout the day.

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

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

One of the most comprehensive studies to date measured 52 blood markers and found no adverse effects following 21 months of supplementation (8).

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

Although people often believe it can cause dehydration and cramps, this is not supported by research. In fact, studies have shown it can reduce cramps and dehydration during endurance exercise in high heat (53, 54).

You can read more about creatine's safety and side-effect profile in this article.

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