Creatine is generally considered to be a safe supplement for most people when taken within recommended doses. Multiple studies and reviews support its safety profile:

1. Short-term Safety: Creatine supplementation up to 25 grams daily for up to 14 days, or lower doses of 4-5 grams daily for up to 18 months, have been used safely by most people¹.
2. Long-term Safety: Long-term creatine supplementation (doses up to 10 grams daily for up to 5 years) has also shown a good safety profile, with no significant adverse effects on renal, hepatic, or cardiovascular functions in healthy individuals¹².
3. Anecdotal Reports: Some side effects like muscle cramping, gastrointestinal symptoms, and changes in renal and hepatic laboratory values remain largely anecdotal, and causality has not been well-established².
4. Clinical Markers: Long-term supplementation (up to 21 months) does not significantly affect clinical markers of health in athletes undergoing intense training compared to those who do not take creatine³.
5. Special Populations: Creatine might exacerbate certain conditions such as bipolar disorder, kidney disease, and Parkinson's disease. People with these conditions should consult healthcare professionals before using creatine¹.
6. Contaminants: Potential contaminants from industrial production of creatine could pose risks, but high-quality production standards generally minimize these concerns².

In summary, when used responsibly and in appropriate doses, creatine is considered safe for most individuals. However, specific populations with pre-existing health conditions should seek medical advice before supplementation.

Footnotes

1. MedlinePlus Supplements ↩ ↩² ↩³

2. PubMed - Is the use of oral creatine supplementation safe? ↩ ↩² ↩³

3. PubMed - Long-term creatine supplementation does not significantly affect clinical markers of health in athletes ↩