A Guide to Creatine: Muscle and Brain Health

Medically Reviewed By Adam Bernstein, MD, ScD
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Creatine is a popular supplement among athletes and people who exercise. People take it to improve muscle mass, enhance athletic performance, and help with recovery. The brain and muscles, including the heart, all use creatine for energy. Most sports supplements contain creatine. It is one of the most well-studied supplements available. It also appears safe, which is not always the case for supplements.

The body makes creatine, which is also naturally available in red meat and fish.

This article provides an overview of creatine, including its role in body functions, supplement health benefits, dosage, and side effects.

What is creatine?

Person drinking protein shake
Ezequiel Giménez/Stocksy United

Creatine is a naturally occurring compound derived from amino acids. Your body makes it out of three amino acids:

  • arginine
  • glycine
  • methionine

The kidneys, liver, and pancreas are the main organs that produce creatine.

You can also get creatine in your diet by eating red meat or seafood. People who do not eat these proteins may lack adequate creatine. Creatine levels in vegetarians can be up to 30% lower than in people who eat meat and fish. 

What does creatine do in the body?

Creatine primarily plays a role in energy storage and usage. The body stores 95% of the creatine in skeletal muscles. There, the body uses it for energy and helps muscles contract. Other tissues with high metabolic activity also use creatine, including the:

  • brain
  • heart
  • retina
  • sperm

Your body breaks down about 1–2% of stored creatine each day. The waste product of this process is creatinine, which enters the blood system. Healthy kidneys can filter out creatinine and excrete it in the urine.

People with more muscle mass break down more creatine daily. This is also true for people with higher levels of physical activity.

How does creatine help build muscle?

Creatine does not directly increase muscle mass. Due to this, the International Olympic Committee (IOC), the National Collegiate Athletic Association (NCAA), and various professional sports associations do not prohibit its use.

Creatine’s role in building muscle hinges on anaerobic energy. You need this energy to build and maintain lean muscle mass.

Creatine increases the energy available to your muscles during anaerobic activity. This extra energy may allow you to intensify your exercise, such as:

  • increasing the weight you lift
  • increasing repetitions
  • increasing the time you spend exercising

Anaerobic activity is what ultimately builds muscle tissue. Aerobic energy may also play a role in building and maintaining muscle mass.

How does creatine affect the brain?

The brain is one of the tissues with a high metabolic activity using creatine. In the nervous system, creatine has neuroprotective effects. 

Low levels of creatine in the brain correlate to:

A long-term nutritional strategy aims to increase brain creatine for people with these conditions. This strategy includes lifelong creatine supplementation based on 0.3–0.8 grams (g) per kilogram (kg) of body weight per day. Doctors consider this a high dose.

The National Institutes of Health (NIH) states that long-term use of creatine supplements is possibly safe. They note that people have safely used up to 10 g per day for up to 5 years.

Research has been inconsistent on whether creatine supplements can affect brain health. The results of six clinical trials involving 281 people find evidence of improvement in short-term memory and reasoning with creatine supplementation. However, there were conflicting results for these other cognitive areas:

  • long-term memory
  • spatial memory
  • attention span
  • executive function, such as self-control and response inhibition
  • word fluency, the ability to list words from a given category
  • response time
  • mental fatigue, a state of mental tiredness

Animal and human studies suggest creatine may also help with stroke, brain, and spinal cord injuries. It may reduce the severity of these injuries by increasing the energy available to the brain.

Sex and gender exist on a spectrum. This article uses the terms “female” and/or “male” to refer to sex that was assigned at birth. 

Learn more about the difference between sex and gender here.

What is a creatinine blood test?

Creatinine is a breakdown product of creatine. Doctors measure creatinine in two ways:

  • Serum creatinine test: This is a simple blood test. The normal range for a serum creatinine test is 0.5–1.10 milligrams per deciliter (mg/dl) for females and 0.7–1.30 mg/dl for males.
  • Creatinine clearance test: This test involves collecting all the urine you pass within a timeframe, usually 24 hours. This test measures how much creatinine has passed through your kidneys into your urine. The normal range for a creatinine clearance test is 90–140 milliliters per minute (ml/min) for an average adult.

Different labs may have different ranges. Your doctor will know the ranges specific to the lab they use.

Creatinine levels in the blood or urine reflect activity and creatine stores in the body. The amount of creatinine the body makes from creatine correlates to lean muscle mass. Males make more creatinine than females. Highly active people of any sex will have higher levels than those who are sedentary.

Creatinine level testing is useful for assessing kidney function. The kidneys filter creatinine out of the blood, along with other waste products. Muscle mass typically remains steady from day to day, so creatinine levels in the blood stay fairly constant. Creatinine is a good marker for kidney function because it shows up in the urine, and the body consistently makes it.

A high creatinine test result could be a sign of kidney problems. However, a creatinine result alone is not enough to determine this. A high test result could also reflect your activity level, body composition, or dehydration.

What are the safety and dosages for supplementing creatine?

Taking creatine supplements by mouth at recommended dosages is generally safe for healthy people.

Doctors consider the following dosages over these periods to be generally safe:

  • A higher dosage is 25 g daily for up to 14 days.
  • A lower dosage is 4–5 g daily for up to 18 months.
  • For longer durations, up to 10 g daily for up to 5 years is safe.

In children, short-term usage is considered generally safe at these dosages:

  • Children ages 2–5 years can take 2 g per day for 6 months.
  • A child can take 0.1–0.4 g/kg of body weight daily for up to 6 months.

Who should not supplement with creatine?

People with kidney disease or other conditions, including pregnancy, should talk with their doctor about all supplements. This includes creatine.

What are the benefits of supplementing creatine?

Health benefits of taking supplemental creatine include:

  • improved athletic performance in certain sports activities
  • improved muscle strength in adults of all ages
  • improved muscle strength in older adults with age-related muscle loss

Supplemental creatine can also help balance creatine deficiencies resulting from creatine metabolism disorder. This condition can affect the brains of children and young adults.

Doctors recommend a 12-week course of creatine supplements and muscle-building exercise for age-related muscle loss.

Other frequently asked questions

Here are some other questions people often ask about creatine.

How much creatine per day do you need?

An average-sized person needs 2–3 g per day to replace creatine stores. However, the exact number depends on their muscle mass, diet, and physical activity. People who do not regularly eat red meat or fish may need more.

One method to saturate creatine stores is to supplement with 5 g four times per day for 5–7 days. After that, doctors recommend maintaining supplementation with 3–10 g per day, depending on a person’s body size. Consult with your doctor for guidance on supplementation.

Do creatine supplements make you gain weight?

Weight gain is a consistent side effect of creatine supplements. Creatine is osmotically active, meaning it can cause you to retain water. As a result, the weight gain is likely due to your muscles holding onto more water. This can also make the muscles appear larger.

Is creatine an anabolic steroid?

The physical and performance results of anabolic steroids and creatine supplements are similar, including increasing muscle mass. Anabolic steroids are drugs and controlled substances. Creatine is a nutritional supplement with a completely different chemical makeup. Creatine is not a controlled substance.


Creatine is a popular and widely used supplement for sports and athletics. However, it has potential benefits outside of building muscle mass. Part of its appeal is its safety record. It is generally safe for healthy people to use at recommended dosages.

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Medical Reviewer: Adam Bernstein, MD, ScD
Last Review Date: 2022 Sep 29
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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