Is there a bad side effect of creatine?: A scientific look at the supplement's safety

October 10, 2025 •

3 min read

According to the International Society of Sports Nutrition (ISSN), hundreds of studies support creatine's safety and effectiveness. It is consistently one of the most researched and beneficial supplements available, yet concerns persist, making it important to understand if there is a bad side effect of creatine.

Quick Summary

Despite persistent myths, creatine is generally considered safe for healthy individuals when taken at recommended doses. Research has debunked concerns about kidney damage, dehydration, and hair loss, while acknowledging temporary effects like water retention and mild digestive issues with high doses.

Key Points

Creatine is Safe for Healthy Individuals: Extensive, long-term research confirms that creatine supplementation does not cause harm to the kidneys or liver in healthy people when taken at recommended doses.
Bloating is Temporary and Dose-Dependent: Initial water retention and bloating during a high-dose loading phase are temporary and can be avoided by starting with a standard maintenance dose.
Dehydration and Cramps Are Myths: Contrary to popular belief, studies show creatine does not cause dehydration and may actually help prevent muscle cramps when used properly.
Hair Loss Link is Weak: The connection between creatine and hair loss is based on a single, limited study. Subsequent research has not confirmed a causal link, and genetic predisposition is the primary factor.
Quality and Health Conditions Matter: Choose a third-party tested creatine product and consult a healthcare professional before use, especially if you have pre-existing kidney, liver, or bipolar conditions.
Mild Digestive Issues are Possible: High, single doses of creatine may cause mild digestive upset, but this can be minimized by dividing doses or sticking to a low maintenance dose.

Creatine Myths vs. Scientific Reality

Creatine is a naturally occurring compound crucial for cellular energy, especially in muscles. While its benefits for performance and muscle mass are established, myths about its safety are common. Most fears are unfounded with responsible use. Let's examine common concerns against scientific evidence.

Creatine and Kidney Health: Is There a Bad Side Effect of Creatine?

A frequent myth is that creatine damages kidneys. This misunderstanding often arises because creatine's breakdown product, creatinine, is used in kidney function tests. Increased creatinine after supplementation is mistakenly seen as kidney issues. However, extensive research in healthy individuals shows no evidence of kidney or liver harm from creatine. Healthy kidneys efficiently filter the increased creatinine. A long-term study in 2001 found no negative effects on organ function in healthy athletes over four years. Individuals with existing kidney disease should consult a doctor.

The Truth About Dehydration and Muscle Cramping

Another myth is that creatine causes dehydration and cramps by drawing water into muscles. Studies show creatine's effect on cellular water is minor and doesn't cause dehydration. Research on college athletes even found fewer instances of dehydration and cramps in those taking creatine. Staying hydrated is essential for active individuals, regardless of creatine use.

Does Creatine Cause Hair Loss?

The idea that creatine causes hair loss stems mainly from one 2009 study linking it to increased DHT, a hormone related to hair loss. However, subsequent studies haven't supported these findings or shown effects on hair follicles. Experts generally agree that creatine isn't a confirmed cause of hair loss, with genetics being the primary factor in pattern baldness.

Acknowledging the Actual Side Effects

While many reported side effects are myths, some temporary effects can occur, particularly during a loading phase or with high doses. These are usually mild.

Potential, Temporary Side Effects:

Bloating and Water Retention: During a loading phase (20-25 grams/day for 5-7 days), creatine can cause temporary water weight gain and bloating as water is drawn into muscle cells. This typically decreases during the maintenance phase (3-5 grams/day). Skipping the loading phase can help avoid this.
Digestive Discomfort: High single doses may lead to mild issues like nausea or diarrhea. Splitting larger doses or using the standard maintenance dose can prevent this.
Minor Weight Gain: Any weight increase is due to muscle mass and water retention, not fat. This is often a desired effect, but athletes in weight-class sports should be aware.

Creatine Side Effects: Myth vs. Fact


Perceived Side Effect	Scientific Reality
Kidney Damage	No adverse effects on kidney function in healthy individuals shown by extensive research.
Liver Damage	No negative impact on liver function in healthy people indicated by long-term studies.
Dehydration	Myth debunked; creatine does not cause dehydration and may improve hydration.
Muscle Cramps	Incorrectly linked to dehydration; studies suggest creatine may help prevent cramping.
Hair Loss	Based on limited evidence; genetic factors are the main cause of baldness.
Bloating	Temporary water retention during high-dose loading phases. Avoidable with lower doses.

Quality and Medical Precautions

Supplement quality is vital, as the FDA doesn't strictly regulate them. Look for third-party tested products for purity. Creatine monohydrate is the most studied and recommended form. Creatine isn't suitable for everyone without medical guidance. This includes individuals with pre-existing kidney or liver disease, diabetes, or bipolar disorder. Pregnant or breastfeeding women and those taking certain medications should also consult a doctor.

Conclusion: The Safety Profile of Creatine

Concerns about whether there is a bad side effect of creatine are mostly based on misunderstandings rather than science. For most healthy adults, creatine is a safe and effective supplement with strong research backing. Minor, temporary effects like bloating or digestive upset are possible but often dose-dependent and manageable. Fears about kidney damage, dehydration, and hair loss have been extensively disproven by studies. Always choose a quality product and consult a healthcare professional, especially with pre-existing health conditions. Used properly, creatine is a valuable tool for performance and muscle growth.

For more information on the science behind creatine, a comprehensive review is available from the International Society of Sports Nutrition.

Frequently Asked Questions

No, numerous studies have shown that creatine is safe for healthy kidneys when taken at recommended doses. Concerns often arise from an increase in creatinine levels, a waste product of creatine metabolism, which is not an indicator of kidney dysfunction in healthy individuals.

The link between creatine and hair loss is speculative and based on weak evidence from a single study. Robust, more recent research has not found a connection, and genetic predisposition is the primary determinant of hair loss.

No, bloating is usually temporary and occurs during the initial loading phase due to water retention in the muscles. It typically resolves once you switch to a lower, daily maintenance dose.

This is a common myth. Studies have found no evidence that creatine causes dehydration or cramps. In fact, some research suggests it may help prevent these issues, especially in hot environments.

Individuals with pre-existing kidney disease, liver disease, diabetes, or bipolar disorder should avoid creatine or consult a doctor first. Pregnant or breastfeeding women and those under 18 should also avoid it due to a lack of sufficient research.

Excessive doses can increase the risk of side effects like gastrointestinal distress (diarrhea, upset stomach) and water retention. Sticking to the recommended daily maintenance dose of 3-5 grams is best.

Not all supplements are created equal. It is important to choose a high-quality product, preferably creatine monohydrate, from a reputable brand that is third-party tested for purity and accuracy.