Creatinine is the standard marker of kidney function but is produced in proportion to muscle mass, making it unreliable in high-muscle-mass athletes. An athlete with 100 kg of lean mass will have elevated creatinine from muscle turnover alone, triggering false-positive kidney disease screening. Cystatin C is a kidney filtration marker not influenced by muscle mass, making it the superior renal marker for athletes and AAS users.
GearCheck connects glossary concepts to your actual bloodwork — showing exactly where your values sit and what they mean in the context of your protocol.
Analyze My Bloodwork →GearCheck provides blood marker analysis and harm reduction education. Information is for educational purposes only and does not constitute medical advice. Always consult a healthcare professional.