Creatinine
Kidney Function marker
Creatinine
Waste product from muscle metabolism. Elevated levels may indicate reduced kidney function.
PED Notes
CRITICAL: Creatinine is directly proportional to muscle mass. Heavily muscled athletes will consistently show 'elevated' creatinine that is perfectly normal for their body composition. Creatine supplementation also elevates creatinine. Standard reference ranges are inappropriate for muscular individuals. Values up to 130 umol/L are common and normal. If creatinine is elevated, confirm kidney function with a Cystatin C test -- Cystatin C is not affected by muscle mass and gives a more accurate kidney assessment.
When high
Supplements:
- Astragalus -- 500-1000mg/day, kidney support
Lifestyle:
- Increase water intake (3-4L/day)
- Reduce creatine supplementation temporarily before testing
- Monitor protein intake if levels remain high
- Request Cystatin C test to confirm true kidney function
Why muscular athletes get flagged for kidney damage they do not have, and the test that settles it: Why muscular athletes get false kidney failure diagnoses.
Educational information, not medical advice. Nothing here is a prescription or a treatment plan, and it does not account for your history, medications or conditions. Use it to ask better questions: bring it to your doctor and decide together. Full disclaimer.
History Chart
Reading History
Frequently Asked Questions
Reference Ranges
Standard Range
VitalMetrics Range