Which Organ is Negatively Affected the Most by Creatine? A Closer Look at the Science

October 18, 2025 •

4 min read

According to numerous large-scale studies, creatine supplementation does not cause harm to the kidneys or liver in healthy individuals when taken at recommended doses. The concern over which organ is negatively affected the most by creatine often stems from a misunderstanding of how the body processes this popular supplement.

Quick Summary

Creatine supplementation is safe for healthy kidneys and liver within recommended doses, contrary to popular belief. Elevated creatinine levels are a normal metabolic byproduct, not an indicator of organ damage. Users with pre-existing conditions should consult a doctor before use.

Key Points

Kidneys Filter Creatinine: The main interaction between creatine and the kidneys involves the filtration of creatinine, a harmless metabolic byproduct of creatine.
No Damage in Healthy Individuals: Scientific research and meta-analyses confirm that creatine does not cause kidney or liver damage in healthy people at recommended doses.
Elevated Creatinine is Normal: A rise in serum creatinine is a normal and expected side effect of creatine supplementation and does not indicate kidney damage in healthy users.
Pre-existing Conditions are a Risk: Individuals with a history of kidney or liver disease should avoid creatine or consult a healthcare professional before use.
Hydration is Key: Proper hydration is essential when taking creatine, as the supplement draws water into the muscles.
Liver is Unaffected: The liver, which synthesizes creatine, is not negatively impacted by supplementation in healthy people.

Creatine and the Kidney: Understanding the Creatinine Connection

One of the most persistent myths surrounding creatine is its supposed danger to the kidneys. The basis for this concern lies in the body's natural metabolic process. Creatine is converted into a waste product called creatinine, which the kidneys filter from the bloodstream. When a person supplements with creatine, they have more total creatine in their body, leading to a natural and harmless increase in creatinine levels. For a person with healthy kidneys, this is a normal metabolic function, not a sign of damage.

Many doctors and patients have been confused by this phenomenon in the past. Standard blood tests for kidney function often measure serum creatinine levels to estimate the glomerular filtration rate (eGFR). An elevated level can sometimes trigger a false alarm, suggesting a problem where none exists. However, physicians are now more aware of this effect and can order additional, more precise tests like a cystatin C test to confirm true kidney function. Large-scale meta-analyses and long-term controlled studies confirm that creatine is safe for the kidneys of healthy individuals. The only significant risk is for individuals with pre-existing chronic kidney disease (CKD), who should avoid creatine unless under a doctor's supervision.

Creatine and the Liver: Unfounded Concerns

The liver's role in creatine metabolism is to help synthesize it from amino acids, not to filter it in the same manner as the kidneys. Concerns about liver damage are largely unfounded for healthy individuals taking recommended dosages. Several studies, including population-based research from NHANES, have investigated the link between dietary creatine intake and liver health. These studies found no association between higher creatine intake from food and an increased risk of liver disease manifestations like fibrosis or cirrhosis.

Like with the kidneys, rare case reports of liver issues exist, but these are often confounded by factors like extreme dosages, use of other substances (such as alcohol or anabolic steroids), or pre-existing liver conditions. Preclinical animal studies showing liver issues often use much higher, unregulated doses that do not reflect typical human consumption. For the vast majority of healthy people, creatine supplementation does not negatively impact liver enzymes or function.

Role of Hydration and Dosage in Organ Health

While creatine is generally safe, proper hydration is crucial for supporting overall health, including kidney function. Creatine draws water into the muscle cells, and without adequate water intake, some individuals might experience cramps or digestive issues. However, studies suggest that creatine may have a hyper-hydrating effect, which could protect against dehydration during exercise. Sticking to recommended dosages, typically 3-5 grams per day for maintenance, is also key to avoiding side effects like gastric distress. Taking excessively high doses, such as 20 grams at once, has been shown to increase the risk of diarrhea.

Comparison: Creatine's Effects on Kidneys vs. Liver


Aspect	Kidneys (in healthy individuals)	Liver (in healthy individuals)
Primary Interaction	Filters the waste product, creatinine.	Synthesizes creatine; metabolizes waste.
Risk of Damage	No evidence of damage at recommended doses.	No evidence of damage at recommended doses.
Elevated Marker	Elevated serum creatinine (not indicative of damage).	Potentially elevated liver enzymes (rare, inconsistent evidence).
Processing Load	Increased filtration load due to more creatinine.	Manages synthesis and metabolic byproducts without stress.
Primary Concern	Misinterpretation of blood test results.	Potential masking of pre-existing conditions.

Conclusion: The Final Verdict

So, which organ is negatively affected the most by creatine? The answer, for healthy individuals, is neither. Extensive research and clinical trials have debunked the long-standing myth that creatine is harmful to the kidneys or liver. The kidneys are most involved in the excretion of creatine's waste product, creatinine, but this process does not cause damage in a healthy individual. An increase in blood creatinine is a normal metabolic sign of supplementation, not a cause for concern. Similarly, the liver's role in synthesizing creatine is well-managed and not burdened by recommended dosages. The strongest negative impact is seen in those with pre-existing kidney or liver conditions, for whom the supplement is generally not recommended. As with any supplement, ensuring adequate hydration and following dosage guidelines is prudent. For those with underlying health issues, consulting a healthcare provider is the safest course of action. Examine.com provides an excellent breakdown of the research supporting creatine's safety profile.

Note: It's important to remember that these conclusions apply to the most widely studied form, creatine monohydrate, and to reputable, high-quality products.

How Creatine Interacts with Your Organs

Creatine plays a vital role in cellular energy and is naturally produced by the liver and kidneys, while the majority is stored in muscles. Supplementation boosts these stores, which helps with short bursts of high-intensity exercise. The body naturally converts creatine to creatinine, which is then filtered and excreted by the kidneys. In a healthy body, this process functions normally without causing harm to either the kidneys or liver.

Creatine's Effect on Energy and Muscles

ATP production: Creatine helps replenish Adenosine Triphosphate (ATP), the primary energy source for cellular activity, particularly during high-intensity, short-duration exercise.
Increased muscle mass: By allowing for harder, more intense workouts, creatine indirectly helps increase muscle growth and strength.
Water retention: The supplement causes muscles to retain water, contributing to an increase in body weight, which is not fat mass.

Factors that Influence Creatine's Impact

Dosage: Excessive doses can increase the risk of digestive issues, so staying within the recommended 3-5g daily is best.
Purity: Using third-party tested products (e.g., NSF Certified) reduces the risk of consuming contaminated supplements.
Underlying Health: Individuals with pre-existing kidney or liver conditions are most at risk and should consult a doctor.

Frequently Asked Questions

There is no scientific evidence to support the claim that creatine supplementation causes kidney stones in healthy individuals. Case reports linking creatine to kidney stones have been rare and often involve other confounding factors.

Creatine is naturally converted into creatinine, a waste product. When you supplement with creatine, your body’s total creatine store increases, leading to a normal and harmless rise in the amount of creatinine produced.

No, if your kidneys are healthy. The high creatinine level is a harmless artifact of the supplementation. A doctor who knows you take creatine can order alternative, more accurate tests for kidney function, such as a cystatin C test.

For healthy individuals, creatine does not cause liver damage. The liver plays a role in synthesizing creatine, and studies have shown no significant negative effects on liver enzymes when the supplement is taken at recommended doses.

No. Individuals with pre-existing kidney disease or at high risk of kidney dysfunction should not take creatine unless specifically cleared by a healthcare provider.

Creatinine levels typically return to their baseline within a few weeks after discontinuing creatine supplementation. The exact timeframe can vary depending on the individual.

No, creatine does not cause dehydration. It draws water into the muscle cells. However, it's important to drink enough water while using creatine to stay properly hydrated and support overall bodily function.