Potential Side Effects of Creatine Monohydrate Supplementation
Creatine monohydrate supplementation is generally safe for healthy individuals, with water retention being the most common side effect during initial supplementation periods. 1
Common Side Effects
- Water retention: Most common side effect, typically occurring during the initial loading phase
- Weight gain: 1-2.3% increase in body mass, primarily attributed to increases in fat-free mass 2
- Gastrointestinal disturbances: Occasional reports of digestive discomfort 3
- Muscle cramps: Anecdotally reported but not consistently demonstrated in controlled studies 3
- "Fishy" body odor: May occur at doses around 3g/day 1
Safety Profile
Creatine monohydrate has been extensively studied and demonstrates a strong safety profile:
- Kidney function: No evidence of kidney dysfunction in healthy individuals, even with several months of supplementation 4, 3
- Liver function: No significant changes in liver enzymes or function with proper supplementation 4, 3
- Laboratory values: May cause transient increases in serum creatinine levels that could mimic kidney disease but do not represent actual renal impairment 5
Contraindications
Creatine supplementation should be avoided in:
- Individuals with pre-existing kidney disease
- People with diabetes
- Those with hypertension
- Individuals with reduced glomerular filtration rate 1, 4
Dosing Considerations
The American College of Sports Medicine recommends:
- Loading phase: 20g/day divided into four 5g doses for 5-7 days (optional)
- Maintenance phase: 3-5g/day 1, 6
Alternative approaches include:
- Lower dose of 3-5g/day without loading (takes longer to achieve effects)
- Acute dosing with a single high dose of 0.35g/kg for immediate effects 1
Important Precautions
- Maintain adequate hydration when using creatine supplements 1
- Discontinue use if experiencing unusual symptoms 1
- Choose quality supplements tested by reputable third-party testing programs (e.g., 'Informed Sport' or 'HASTA') 1
- Be aware that approximately 15-25% of nutritional supplements may contain undeclared substances 1
Long-term Safety
While most studies focus on short to medium-term supplementation, limited evidence on long-term use (up to 5 years) has not shown adverse effects in healthy individuals 3. However, monitoring is recommended for extended use.
Special Considerations
- Vegetarians may experience more pronounced benefits due to lower baseline creatine levels 1
- Pre-supplementation kidney function assessment might be considered for safety, though not necessary for healthy individuals 4
Remember that while creatine is generally safe, individual responses may vary, and any unusual symptoms should prompt discontinuation and medical consultation.