Are there side effects to taking creatine?

December 27, 2025 •

4 min read

Over two decades of research have consistently shown creatine to be one of the most effective and safest dietary supplements for enhancing exercise performance and increasing muscle mass. This extensive body of scientific evidence helps to clarify and address common concerns, providing a definitive answer to the question: are there side effects to taking creatine?

Quick Summary

Creatine is generally considered safe for healthy individuals when used as recommended. While minor side effects like temporary water weight gain or gastrointestinal discomfort can occur, most serious adverse effects, including kidney damage, are largely unfounded myths debunked by extensive research.

Key Points

Creatine is Safe for Healthy Individuals: Extensive research over 20+ years shows creatine has a strong safety profile and is one of the most well-researched supplements available.
Kidney and Liver Damage Are Myths: Concerns about kidney and liver harm are unfounded in healthy populations, often stemming from misunderstanding how creatine affects creatinine levels.
Dehydration and Cramps Are Not Caused by Creatine: The claim that creatine causes dehydration and cramping is not supported by scientific evidence; some research suggests it may even offer protective hydration benefits.
Temporary Weight Gain Is Normal: The most consistent side effect is weight gain, which is primarily due to increased water content in muscles, not fat gain.
GI Distress is Dosing Dependent: Gastrointestinal issues like bloating or upset stomach are rare at standard doses and most often occur with excessive intake, especially during loading phases.
Pre-Existing Conditions Require Caution: Individuals with kidney or liver disease should consult a doctor before using creatine to ensure it is safe for their specific health needs.

Debunking Common Creatine Side Effect Myths

The Truth About Kidney and Liver Damage

One of the most persistent myths surrounding creatine is its supposed danger to the kidneys and liver. However, this concern has been extensively researched and largely disproven in healthy populations. The misconception likely stems from the fact that creatine supplementation can slightly elevate blood levels of creatinine, a waste product of muscle activity. Since doctors use creatinine levels to test for kidney function, an uneducated observer might mistakenly interpret this increase as a sign of organ damage. Numerous studies, some lasting up to five years, have found no evidence of negative effects on kidney or liver function in healthy individuals using recommended creatine dosages. The International Society of Sports Nutrition (ISSN) explicitly states that creatine is safe for healthy people, from infants to the elderly. That said, caution is advised for individuals with pre-existing kidney disease, who should consult a doctor before starting supplementation.

Addressing Concerns of Dehydration and Cramping

Another widespread, but unsupported, myth is that creatine causes dehydration and muscle cramps. This idea arose from creatine's osmotic effect, which draws water into muscle cells to help with energy production. Early speculation suggested this could pull water from other parts of the body, leading to dehydration. However, modern research refutes this. A 2009 systematic review and other studies have found no evidence linking creatine to dehydration or muscle cramps. In fact, some evidence suggests creatine might have a hyper-hydrating effect, potentially protecting against dehydration and cramping, especially when exercising in hot conditions. As with any exercise regimen, staying adequately hydrated is always crucial, but creatine itself does not appear to be the cause of these issues.

Documented and Potential Side Effects

Weight Gain from Water Retention

The most consistently reported side effect of creatine is weight gain. For most users, this is not a negative side effect but a direct result of the supplement's effectiveness. Creatine draws water into the muscle cells, a process called cellular hydration, which is beneficial for performance and can lead to a noticeable increase in body weight, particularly during the initial "loading phase". It is important to remember this weight gain is from water, not fat. Over the long term, any additional weight gain is likely due to increased muscle mass from more effective workouts.

Gastrointestinal Distress

While relatively uncommon, some individuals may experience gastrointestinal distress, such as an upset stomach, bloating, or diarrhea. This is most often associated with taking excessive doses, particularly during the initial high-dose loading phase. Research suggests that splitting a loading dose (e.g., 20 grams) into smaller, more frequent servings throughout the day can mitigate this risk. Sticking to the standard maintenance dose of 3-5 grams per day also significantly reduces the likelihood of GI issues. Ensuring you choose a high-quality, reputable creatine product can also help, as some issues may be caused by impurities.

Who Should Exercise Caution?

Though widely regarded as safe for healthy people, certain populations should consult a healthcare provider before using creatine:

Individuals with Pre-Existing Kidney or Liver Conditions: Although creatine does not cause organ damage in healthy people, those with compromised kidney or liver function may be advised against its use.
Pregnant and Breastfeeding Women: Due to a lack of sufficient research on its effects in these populations, avoiding creatine is recommended.
Those on Specific Medications: Creatine may interact with certain medications that affect kidney function, such as NSAIDs and diuretics. It is always best to consult with a doctor.

Understanding Creatine Side Effects: A Comparison


Feature	Mythical Side Effects (Largely Debunked)	Documented Side Effects (Usually Minor)
Kidney/Liver Damage	Severe, long-term damage, organ failure.	No evidence of harm in healthy individuals at recommended doses; caution advised for those with existing conditions.
Dehydration/Cramping	Severe dehydration, chronic cramping.	No link found; some studies suggest a hyper-hydrating effect and reduced cramps.
Weight Gain	Gaining excess body fat.	Gain is from water retention in muscles, not fat; long-term gain is from muscle mass.
Gastrointestinal Issues	Severe and common diarrhea and bloating.	Occasional discomfort, primarily with high doses; can be minimized by smaller servings.

How to Minimize Risk and Maximize Safety

Use High-Quality Supplements: Opt for products that have been third-party tested (e.g., NSF Certified) to ensure purity and avoid contaminants.
Stick to Recommended Doses: The standard maintenance dose is 3-5 grams per day. If performing a loading phase, split the 20-gram daily dose into four smaller servings to reduce the risk of stomach upset.
Stay Hydrated: While creatine doesn't cause dehydration, adequate water intake is always important for overall health and for assisting the muscles with hydration.
Consult a Professional: Talk to a healthcare provider or a registered dietitian before starting any new supplement, especially if you have existing health conditions or are taking medication.

Conclusion

After decades of extensive research, the scientific consensus is that creatine is a safe and effective supplement for most healthy individuals. Many of the reported serious side effects, such as kidney damage, liver damage, and dehydration, are based on anecdotal evidence or misinterpretations of data and are not supported by the scientific literature. While some minor, manageable side effects like temporary water weight gain and occasional gastrointestinal distress can occur, these are often linked to improper dosing and can be mitigated by following recommended protocols. By using a quality product and consulting with a healthcare professional, individuals can safely benefit from creatine's proven performance-enhancing effects. For more information on creatine safety, consider reviewing the comprehensive position stand from the International Society of Sports Nutrition (ISSN).

International Society of Sports Nutrition (ISSN) position stand on creatine

Frequently Asked Questions

No, numerous studies have shown that creatine does not cause kidney damage in healthy individuals when taken at recommended dosages. The myth is based on a misunderstanding of how creatine affects creatinine, a marker of kidney function.

No, there is no scientific evidence to support the claim that creatine causes hair loss. A link has been suggested due to a single study showing a rise in DHT, but this was not replicated in follow-up research and the connection remains unproven.

Weight gain from creatine, especially during the initial loading phase, is primarily due to water retention in the muscles. Over time, any additional weight gain is attributed to increased muscle mass from more effective training.

Yes, research supports the long-term safety of creatine supplementation in healthy individuals. Studies lasting up to five years have found no adverse health effects at recommended doses.

To avoid stomach upset, particularly during a loading phase, split the daily dosage into smaller, more frequent servings (e.g., four 5-gram servings). Sticking to the standard 3-5 gram maintenance dose also significantly reduces risk.

There is insufficient research on creatine's effects during pregnancy and breastfeeding. Healthcare providers generally advise against its use during these times to ensure safety.

While generally safe, individuals with pre-existing kidney or liver conditions, those who are pregnant or breastfeeding, and those on certain medications should consult a healthcare professional before use.