Understanding Creatine and Creatinine

Though they have similar names, creatine and creatinine are two different compounds. Creatine is a naturally occurring substance in your brain and muscle tissue. Creatinine is the breakdown of creatine in your muscle tissue and occurs after your body digests protein.

The breakdown of creatine to creatinine happens more often in people with more muscle mass, but we all experience some form of it in our bodies from doing any type of physical activity. Creatine is commonly broken down in your urine. Creatine gives your muscles energy, whereas creatinine may tell you more about your body from the byproduct of that energy.

Differences Between Creatine and Creatinine

While creatine and creatinine are similar, they can each tell you different things about your overall health. Although both compounds can be consumed as a supplement, creatine is one of the most popular workout supplements athletes use to build muscle strength.

What Is Creatine? 

Creatine is a molecule naturally found in the body. It is made up of three main amino acids—glycine, arginine, and methionine. It is mainly produced in your liver, kidneys, and pancreas. Small amounts of creatine can also be found in your brain and heart tissue.

Creatine creates energy for your muscles by replenishing adenosine triphosphate (ATP) in your body. ATP is a molecule that helps provide energy for muscle contractions and nerve function. It can also help your muscles recover after intense exercise.

Athletes might want more creatine before of how physically active they are. You can increase its levels in your body by eating foods with a lot of creatine. Animal-based foods like red meat and fish offer creatine, but plant-based foods typically do not.

What Is Creatinine?

Creatinine is a waste product that is caused by the breakdown of creatine. It is also created during digestion and from consuming protein sources like fish. Around 1–2% of creatine stored in the muscles is broken down into creatinine before leaving the body when you urinate. People who exercise frequently and have more muscle mass tend to have higher creatinine levels.

Your healthcare provider can use urine samples to test creatinine levels and learn more about your kidney health. Your kidneys help get rid of waste in your body. If creatinine levels remain high for an extended period of time, you may be more at risk for chronic kidney disease and kidney stones from the build-up of waste in your body.

People with compromised kidneys may experience a buildup of creatinine in the blood and difficulty getting rid of it through urine.

Health and Fitness

Creatine and creatinine are important compounds, but each can tell your provider different things about your health. Creatine is commonly used as a supplement, whereas creatinine is more of a health marker.

A healthcare provider can test your creatinine levels to assess the health of your kidneys. For people living with kidney disease, higher creatinine levels may be a sign of worsening kidney function. Your healthcare provider may also perform a blood test called the GFR (glomerular filtration rate). Healthcare providers use the amount of creatinine in your blood to detect your GFR. The higher your GFR, the more creatinine that is present in your blood.

Creatinine can also be used in capsule form. Consuming creatinine helps increase muscle mass by increasing the amount of time it takes for your muscles to break down over time as you age. A healthcare provider may recommend them for elderly or immunocompromised people to build muscle strength.

Creatine is more commonly used as a supplement, especially among athletes. In addition to helping to increase muscle mass, it can enhance athletic performance, help with blood sugar control, and potentially improve brain health. According to research, creatine monohydrate is the most effective type of creatine.

Studies show that taking creatine supplements while resistance training improved muscle growth in the upper and lower body of participants of varying ages. Still, creatine is more effective in younger people.

Potential Side Effects

Creatine has not been linked to any major health concerns, but you may experience some side effects from increased creatine intake. Taking creatine in higher doses of 20 grams (g) per day may lead to water retention (a build-up of fluid in your body). Taking more than 10 g of creatine daily may cause gastrointestinal (GI) conditions like diarrhea.

Taking creatine supplements may also temporarily raise creatinine levels in your blood. However, a temporary elevation of creatinine in the blood does not negatively affect kidney health. You can prevent side effects by limiting your intake to smaller doses of creatine, such as 3-5 g per day.

Risks

Creatine supplements are safe for most people, but it is best to check with your healthcare provider if you are pregnant or breastfeeding.

Although creatine powder is one of the most studied dietary supplements, check with your healthcare provider if you are also taking other medications while consuming creatine powder.

A Quick Review

Creatine helps your body to have the energy it needs to start and recover after a workout. Creatinine is the byproduct of creatine that is broken down in the body after physical activity. Using creatinine, a healthcare provider can learn more about your kidney health.

You can take creatine supplements to gain muscle mass while working out. Protein sources like red meat and fish can increase creatine levels in your body.