Understanding Creatine and Its Reputation
Creatine is a naturally occurring compound synthesized in the liver, kidneys, and pancreas from amino acids [1.5.2]. It's also found in foods like red meat and fish [1.2.3]. Its primary function is to help muscles produce energy during high-intensity exercise or heavy lifting, which is why it's a staple supplement for many athletes seeking to improve strength and muscle mass [1.4.1]. The International Society of Sports Nutrition (ISSN) considers creatine to be one of the most effective and safe ergogenic aids available [1.2.3]. Long-term studies, some lasting up to five years, have not found significant adverse effects in healthy individuals taking recommended doses [1.4.3, 1.4.6]. However, concerns and myths about its safety persist.
Potential Unhealthy Side Effects of Creatine
While creatine has a strong safety profile, some individuals may experience side effects, especially when taking higher-than-recommended doses [1.2.2, 1.3.4].
Gastrointestinal Distress
One of the most commonly reported issues is digestive discomfort, including bloating, stomach pain, and diarrhea [1.3.4, 1.8.5]. This is more likely to occur during a "loading phase," where individuals take large doses (around 20 grams per day) to quickly saturate their muscles [1.8.4]. A study noted that taking a 10-gram dose at once increased the risk of diarrhea by 56% [1.2.3]. The standard maintenance dose of 3-5 grams per day is much less likely to cause these issues [1.2.3, 1.8.2]. The discomfort is often attributed to creatine drawing water into the intestine [1.8.1].
Water Retention and Weight Gain
Creatine is known to cause a rapid increase in body weight, typically within the first week of supplementation [1.3.4]. This is not fat gain, but rather water being pulled into the muscle cells [1.2.3, 1.4.3]. While this intracellular hydration is beneficial for muscle function, the initial weight gain can be a concern for athletes in weight-sensitive sports [1.3.4, 1.2.4]. This effect is generally temporary, and long-term studies do not show a persistent issue with holding excess water [1.3.2]. The long-term weight gain associated with creatine use is typically due to an increase in lean muscle mass, not fat [1.4.3].
The Kidney and Liver Health Debate
Perhaps the most persistent concern is that creatine damages the kidneys and liver. This myth largely stems from the fact that creatine supplementation can slightly elevate blood levels of creatinine, a waste product used to diagnose kidney problems [1.2.3, 1.5.5]. However, for a healthy person, this increase is a normal byproduct of creatine metabolism and does not indicate kidney damage [1.7.5]. Numerous studies on healthy individuals have shown no evidence of harm to the kidneys or liver, even with long-term use [1.2.3, 1.4.2, 1.7.2]. However, the key distinction is pre-existing conditions. Individuals who already have kidney disease, liver disease, or diabetes are advised to avoid creatine or consult a doctor, as the supplement could potentially worsen their condition [1.6.1, 1.6.2, 1.7.1].
Debunking Common Myths
Many other claims about creatine's negative effects lack scientific support.
- Dehydration and Cramping: Contrary to the myth, studies suggest creatine does not cause dehydration or cramping. In fact, by pulling water into the muscles, it may have a hydrating effect and help protect against these conditions, especially when exercising in the heat [1.2.3, 1.9.5].
- Rhabdomyolysis: There is no evidence to support the claim that creatine causes this serious condition of muscle breakdown [1.2.3, 1.7.2]. The confusion arises because a blood marker for rhabdomyolysis (creatine kinase) can be slightly elevated with supplementation, but not to the dangerous levels seen in the actual condition [1.2.3].
- Hair Loss: A single, small 2009 study suggested a link between creatine and an increase in DHT, a hormone associated with hair loss. However, this study has not been replicated, and the broader body of research has not found a direct link between creatine supplementation and baldness [1.5.5].
Creatine Side Effects: Myth vs. Fact
| Claim / Myth | Scientific Fact |
|---|---|
| Causes Kidney Damage | No evidence of harm in healthy individuals. A concern only for those with pre-existing kidney disease [1.7.2, 1.6.2]. |
| Causes Dehydration & Cramps | False. Research suggests it may even reduce the risk of cramping and dehydration by increasing water in muscle cells [1.2.3, 1.9.5]. |
| Is an Anabolic Steroid | False. Creatine is a naturally occurring amino acid compound and has no relation to hormonal steroids [1.2.3, 1.5.2]. |
| Causes Fat Gain | The initial weight gain is water, not fat. Long-term, it helps build muscle mass, which can increase metabolism [1.4.3, 1.5.6]. |
| Causes Digestive Upset | Can be true, especially with high doses (10g+ at once). Sticking to 3-5g daily minimizes this risk [1.2.3, 1.8.5]. |
Who Should Be Cautious or Avoid Creatine?
Despite its general safety, some populations should avoid creatine or consult a healthcare provider before use [1.6.1, 1.6.4]:
- Individuals with kidney or liver disease: These conditions can be exacerbated by creatine supplementation [1.6.1].
- People with diabetes: Creatine may affect blood sugar levels, so medical guidance is essential [1.6.4].
- Pregnant or nursing women: There is insufficient research on the effects of creatine during pregnancy or breastfeeding [1.6.2].
- Adolescents under 18: While some studies show safety in children for medical purposes, use for athletic performance is generally not recommended without a doctor's advice due to a lack of long-term research in this group [1.2.2, 1.6.4].
- Individuals with Bipolar Disorder: There are reports it may increase the risk of mania [1.6.2].
Conclusion: A Balanced View on Creatine's Health Impact
For the vast majority of healthy adults, creatine is a safe and effective supplement for enhancing strength and muscle growth when taken at the recommended dose of 3-5 grams per day [1.3.2]. The unhealthy aspects of creatine are largely confined to mild, dose-dependent side effects like gastrointestinal upset or risks for specific populations with pre-existing health conditions. The more alarming claims, such as kidney damage and dehydration in healthy users, are largely myths that have been debunked by extensive scientific research [1.7.2]. The risk of harm is also elevated by using unregulated products, which may contain contaminants [1.3.4]. Therefore, choosing a third-party tested product and consulting a healthcare provider, especially if you have any underlying health concerns, is the most sensible approach.
For more in-depth information, you can review resources from the Mayo Clinic.
