Can Premier Protein Shakes Raise Serum Creatinine?
Yes, Premier Protein shakes can temporarily elevate your serum creatinine level, but this does NOT indicate kidney damage—it represents a false elevation from increased protein metabolism, not impaired renal function. 1
Understanding the Mechanism
Whey and casein protein supplements increase serum creatinine through normal metabolic processes, not kidney injury. When you consume protein shakes, your body breaks down the protein into amino acids, which increases creatinine production as a normal byproduct of muscle metabolism. 1 This creates a laboratory artifact that mimics kidney disease without actual organ damage. 2
The critical distinction is between:
- False elevation: Increased creatinine from protein metabolism (harmless)
- True kidney dysfunction: Elevated creatinine from impaired filtration (pathologic)
Immediate Action Steps
Calculate your estimated glomerular filtration rate (eGFR) using your age, sex, race, and current creatinine level to determine if you have actual kidney dysfunction. 1 This single calculation determines your entire management strategy:
If eGFR ≥60 mL/min/1.73m²:
- Continue Premier Protein shakes safely—your kidneys are functioning normally. 1
- The elevated creatinine is a benign laboratory finding from protein metabolism. 2
- No dietary restrictions are needed. 3
If eGFR 30-59 mL/min/1.73m² (Stage 3 CKD):
- Limit total protein intake to 0.8 g/kg/day from ALL sources, including Premier Protein. 4, 1
- This is the Recommended Dietary Allowance (RDA) level that balances nutrition without accelerating kidney decline. 4
- Calculate your daily protein budget and track Premier Protein within this limit. 1
If eGFR <30 mL/min/1.73m² (Stage 4-5 CKD):
- Discontinue Premier Protein immediately and restrict total protein to 0.8 g/kg/day. 1
- High protein intake at this stage accelerates kidney function loss and increases cardiovascular mortality. 1
Confirming False vs. True Elevation
Stop Premier Protein for 2-4 weeks and recheck your serum creatinine and eGFR. 1 If creatinine normalizes, this confirms the elevation was false and related to protein supplementation. 2 If creatinine remains elevated, you have underlying kidney disease requiring nephrology evaluation.
Also check urinary albumin-to-creatinine ratio (UACR) to detect early kidney damage that creatinine alone may miss. 1 UACR identifies kidney injury before eGFR declines, providing earlier warning of true kidney disease. 1
Critical Protein Intake Thresholds
Never exceed 1.3 g/kg/day total protein intake, as higher amounts accelerate kidney function decline, increase albuminuria, and raise mortality risk. 1 Most Premier Protein shakes contain 30g protein per serving—calculate how this fits within your body weight-based protein budget.
For context on safe protein ranges:
- 0.8 g/kg/day: RDA level, safe for all kidney function stages. 4
- Up to 2.8 g/kg/day: Studied in athletes without kidney impairment. 3
- Above 1.3 g/kg/day: Avoid if any kidney disease, diabetes, or hyperuricemia. 5, 1
Evidence Quality and Nuances
The strongest evidence comes from recent 2024-2025 guidelines synthesized in Praxis Medical Insights, which clearly distinguish false creatinine elevation from true kidney dysfunction. 1 This is supported by a 2018 randomized trial showing higher protein intake increased serum urea but did NOT impair eGFR, creatinine clearance, or albumin excretion in older adults. 6
However, a 2020 JASN review warns that long-term high protein intake may cause intraglomerular hypertension and progressive kidney damage, particularly from animal protein sources. 7 The key is that these concerns apply to sustained excessive intake (>1.3 g/kg/day) in vulnerable populations, not moderate protein supplementation in healthy individuals. 1
A 2023 umbrella review of systematic reviews found no evidence that protein intake above recommendations specifically triggers kidney disease, with most changes representing physiological regulatory responses rather than pathology. 8
Common Pitfalls to Avoid
Do not assume elevated creatinine equals kidney disease without calculating eGFR and checking UACR. 1 Athletes and protein supplement users frequently have falsely elevated creatinine from increased muscle mass and protein metabolism. 2, 3
Do not restrict protein below 0.8 g/kg/day, as this increases malnutrition risk without improving kidney outcomes. 1 Excessive restriction causes more harm than benefit.
Do not continue high-dose protein supplementation if true kidney dysfunction (eGFR <60) is confirmed. 1 At that point, the risks outweigh benefits.
Ongoing Monitoring Strategy
If continuing Premier Protein with normal kidney function:
- Recheck eGFR and UACR every 6-12 months to detect any early kidney changes. 1
If you have reduced kidney function (eGFR 30-59):
- Monitor eGFR and UACR every 3-6 months while restricting protein. 1