Creatine is generally considered safe for most healthy individuals when used at recommended dosages. Here are some key points on its safety:

1. Short-Term Use: Short-term use of creatine (up to 28 days) is widely regarded as safe without significant adverse effects¹.
2. Long-Term Use: Long-term studies indicate that creatine supplementation can be safe for periods extending up to several years, though comprehensive long-term data are still somewhat limited². The International Society of Sports Nutrition states that there is no scientific evidence to suggest that long-term creatine use poses any health risks to healthy individuals³.
3. Kidney Function: There have been isolated case reports of kidney issues arising from creatine use, particularly at high doses. However, most controlled studies have shown no significant adverse effects on renal function in healthy individuals⁴⁵.
4. Miscellaneous Side Effects: Some users report weight gain (primarily due to water retention), muscle cramping, and gastrointestinal discomfort. These effects are generally mild and not consistent across users⁶.
5. Specific Populations: Individuals with pre-existing kidney conditions or those at risk for renal dysfunction should avoid creatine or use it cautiously while monitoring kidney function⁷.

Overall, creatine appears to be a safe supplement for enhancing athletic performance and exercise capacity when used appropriately by healthy adults.

Footnotes

1. M S Juhn, "Potential side effects of oral creatine supplementation: a critical review," PubMed Central, 1999. ↩

2. G J Groeneveld, "Few adverse effects of long-term creatine supplementation in a placebo-controlled trial," PubMed Central, 2024. ↩

3. Richard B. Kreider, "International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine," PubMed Central, 2017. ↩

4. Basturk Taner, "The effects of the recommended dose of creatine monohydrate on kidney function," PubMed Central, 2010. ↩

5. Hyo Jeong Kim, "Studies on the safety of creatine supplementation," PubMed Central, 2011. ↩

6. J R Poortmans, "Adverse effects of creatine supplementation: fact or fiction?" PubMed Central, 2000. ↩

7. Adam M Persky, "Safety of creatine supplementation," PubMed Central, 2007. ↩