Is Creatine Safe for Your Kidneys?

Creatine is a substance made naturally by the liver, kidneys and pancreas. It is also found in foods such as meat and fish.

Most of the body’s creatine is stored in the muscles, where it helps provide quick energy for activities such as sprinting, weightlifting and other short bursts of intense exercise.

Taking a creatine supplement can increase the amount stored in the muscles. When combined with strength training, this may help improve strength, power and muscle growth. Creatine monohydrate is the most widely studied form of the supplement.

Studies have not found strong evidence that moderate amounts of creatine damage kidney function in healthy adults.

“Studies have found no negative effects on kidney function in healthy adults, and there is no strong evidence that taking moderate amounts of creatine causes kidney injury,” says Dr. Solhjou.

However, many studies have been relatively small or have followed participants for a limited time. Less is known about the long-term effects of creatine or its effects on people who already have kidney disease.

“Creatine supplements are becoming increasingly popular, but long-term research remains limited, particularly for certain patient groups,” says Dr. Solhjou.

Creatine is generally not recommended for people with chronic kidney disease because their kidneys have less reserve and may be more vulnerable to additional stress.

“For patients with chronic kidney disease, I explain it this way: The kidney doesn’t have enough reserve,” says Dr. Solhjou. “Although studies are limited, we still don’t recommend creatine supplementation.”

Talk with your doctor before taking creatine if you:

• Have chronic kidney disease or a history of acute kidney injury
• Have a kidney transplant, one kidney or reduced kidney function
• Have protein or blood in your urine
• Have diabetes, high blood pressure or another risk factor for kidney disease
• Take medications that may affect the kidneys
• Frequently use ibuprofen, naproxen or similar pain relievers
• Are pregnant, breastfeeding or younger than 18

Having one of these risk factors does not necessarily mean you can never take creatine. Your doctor can help you make a decision based on your medical history, medications and lab results.

Yes. Creatine can affect certain kidney test results even when the kidneys are working normally.

Creatine and creatinine are not the same thing. The body converts some creatine into creatinine, a waste product that the kidneys remove from the blood. Doctors measure creatinine levels to help evaluate kidney function.

“Creatine supplements break down into creatinine in the body, which is a marker we check in the blood to learn about kidney function,” says Dr. Solhjou.

If creatinine levels rise, estimated glomerular filtration rate, or eGFR, may fall. This can make kidney function appear worse than it actually is.

“Creatine supplementation can increase creatinine levels, not because the kidney is injured, but because creatine is converted to creatinine,” says Dr. Solhjou. “This could raise concern that there is an issue with kidney function when, in reality, it may simply be a change in the blood level of creatinine and not a true change in kidney function.”

However, an abnormal creatinine result should not automatically be blamed on creatine. An increase also may be caused by dehydration, medication effects, kidney disease or another health condition.

If a creatinine-based result is difficult to interpret, a doctor may repeat the test or recommend additional testing.

“Another test we have, called cystatin C, can be a better marker to check in this setting,” says Dr. Solhjou. “We also commonly recommend that patients stop their supplementation for a few days before testing to see if their kidney number returns to its baseline.”

Do not stop a supplement before testing without first asking your doctor for instructions.

Misinformation about creatine often comes from confusing creatine with creatinine or applying guidance for people with kidney disease to healthy adults.

Myth: Any increase in creatinine means kidney damage

Creatinine is an important measure of kidney health, but many factors can affect it. These include muscle mass, strenuous exercise, meat consumption, hydration and creatine supplementation.

Doctors consider a patient’s health history, changes in lab results, urine test results and other findings rather than relying on one creatinine result.

Myth: Creatine causes kidney disease

Studies have not shown that standard doses of creatine cause kidney disease in healthy adults. People who already have kidney disease or are at increased risk need individualized medical guidance because creatine has not been studied as thoroughly in these groups.

Myth: Creatine always causes dehydration

Creatine draws water into muscle cells, but recommended doses have not been shown to routinely cause dehydration in healthy adults. It is still important to drink enough fluids, especially during strenuous exercise, illness or hot weather.

Myth: Taking more creatine leads to better results

Muscles can store only a limited amount of creatine. Once those stores are full, taking more is unlikely to provide additional benefits. Higher doses may be more likely to cause nausea, diarrhea, bloating or temporary water-weight gain.

Myth: All creatine supplements are the same

Dietary supplements do not undergo the same approval process as prescription medications. Some products may contain contaminants, undeclared ingredients or amounts that do not match the label.

Creatine monohydrate is the most extensively studied form. Look for a product that has been independently tested by a reputable third-party organization for purity and label accuracy.

For most healthy adults who choose to take creatine, a daily dose of 3 to 5 grams of creatine monohydrate is generally enough.

“The recommended dose is 3 to 5 grams per day or 0.1 gram per kilogram of body weight per day,” says Dr. Solhjou.

Some people begin with a loading phase of approximately 20 grams per day, divided into several smaller doses. This can increase muscle creatine stores more quickly, but it is not necessary. Taking a standard daily dose can reach similar levels over several weeks.

Follow the directions on the label and avoid taking several supplements that contain creatine. Because scoops can vary in size, check the dose in grams rather than estimating it by appearance.

If you choose to take creatine, these steps can help you use it more safely:

• Talk with your doctor first. This is especially important if you have kidney disease, risk factors for kidney problems, take prescription medications or use other workout supplements.
• Tell your care team you take creatine. Share the dose, brand, how often you take it and when you last took it before having lab tests.
• Use a moderate dose. Avoid prolonged loading phases or high-dose regimens unless recommended and monitored by a qualified health care professional.
• Stay hydrated. Drink fluids regularly and increase your intake as needed during strenuous exercise, illness or hot weather. Excessive water intake is unnecessary and can be harmful.
• Use medications that may affect the kidneys carefully. Ask your doctor or pharmacist about possible interactions.
• Choose a reputable supplement. Look for independently tested creatine monohydrate.
• Follow up on abnormal test results. Never assume an elevated creatinine level is caused only by the supplement. Work with your doctor to rule out a kidney problem.

Your doctor may recommend baseline kidney testing before you begin taking creatine, especially if you have risk factors. Depending on your health history, ongoing monitoring may also be appropriate.

Stop taking creatine and contact your health care provider if you develop:

• Decreased urination
• Swelling in your legs or around your eyes
• Persistent nausea or vomiting
• Unusual fatigue
• Shortness of breath
• Dark or bloody urine
• Severe muscle pain or weakness

“Because there is a lot of information and misinformation out there, I recommend reaching out to your primary care provider or nephrologist if you have questions about taking creatine supplements,” says Dr. Solhjou.

For most healthy adults, creatine monohydrate appears to be safe for the kidneys when taken at a standard dose of 3 to 5 grams per day. Long-term research remains limited and people with kidney disease or risk factors for kidney problems should talk with their doctor before taking it.

The body converts some creatine into creatinine, which is used to estimate kidney filtration. Taking creatine may raise serum creatinine and make eGFR appear lower even when kidney function has not changed. Because an abnormal result can have other causes, a doctor should evaluate it.

Talk with your doctor first if you have chronic kidney disease, reduced kidney function, one kidney, a kidney transplant, diabetes, high blood pressure or a history of acute kidney injury. Medical guidance is also important if you take medications that affect the kidneys, regularly use NSAIDs, are pregnant or breastfeeding or are younger than 18.

No. A loading phase may increase muscle creatine stores more quickly, but it is not required. A daily dose of 3 to 5 grams can generally reach similar levels over several weeks.

Use a moderate dose, avoid combining multiple creatine-containing products and choose independently tested creatine monohydrate. Stay adequately hydrated and tell your care team about the supplement before having bloodwork. Always follow up with your doctor about abnormal kidney test results.