Creatine & Kidney Health: Is It Safe?

meta-analysis PMID: 31375416

Quick Summary: A recent study looked at whether taking creatine supplements harms your kidneys. The good news? For healthy adults, the research found creatine doesn't seem to cause kidney problems.

What The Research Found

This study reviewed several smaller studies to see if creatine affects kidney function. They looked at things like creatinine levels (a marker of kidney health), how well the kidneys filter waste, and blood urea nitrogen (BUN). The results showed that creatine slightly increased creatinine levels, but this is normal and doesn't mean your kidneys are damaged. The study found no evidence of kidney damage, reduced quality of life, or increased risk of death from taking creatine.

Study Details

Who was studied: Mostly healthy adults.

How long: The studies lasted for at least 4 weeks, with some going longer.

What they took: Participants took creatine supplements in doses ranging from 3 to 20 grams per day.

What This Means For You

If you're healthy: This research suggests that creatine is likely safe for your kidneys if you're a healthy adult.

If you have kidney problems: Talk to your doctor before taking creatine. This study didn't include people with existing kidney issues.

Stay hydrated: Drink plenty of water, especially when taking creatine.

Listen to your body: If you experience any unusual symptoms, stop taking creatine and talk to your doctor.

Study Limitations

Focus on healthy adults: The study only looked at healthy people, so the results might not apply to everyone.

Shorter studies: Most studies were relatively short-term, so we don't know the long-term effects.

Dose variations: The amount of creatine people took varied, which could affect the results.

Key Findings

The meta-analysis concluded that creatine supplementation does not significantly impair renal function in healthy adults. While serum creatinine levels showed a statistically significant increase (standardized mean difference [SMD] = 0.48, 95% CI 0.24–0.73, P = 0.001), this change was deemed clinically irrelevant. No significant effects were observed on estimated glomerular filtration rate (eGFR) or blood urea nitrogen (BUN). The study found no evidence of reduced quality of life or increased mortality risk, contradicting prior concerns about creatine’s safety.

Study Design

This systematic review and meta-analysis evaluated randomized controlled trials (RCTs) published up to 2019. Researchers screened 290 non-duplicated studies, selecting 15 for qualitative analysis and 6 (total n = 248 participants) for quantitative synthesis. Study durations varied, but interventions lasted ≥4 weeks. Participants were generally healthy adults, with no mention of age or gender-specific subgroups in the provided summary.

Dosage & Administration

Creatine doses across included studies ranged from 3–20 g/day. Common protocols included a 5 g/day maintenance dose or a loading phase (e.g., 20 g/day for 5–7 days) followed by maintenance. Supplements were administered orally, typically in powder form mixed with water or juice.

Results & Efficacy

Serum Creatinine: Creatine increased levels (SMD = 0.48, 95% CI 0.24–0.73, P = 0.001), but this aligns with known creatine metabolism (muscle release of creatinine) rather than kidney dysfunction.
eGFR: No significant changes (SMD = −0.05, 95% CI −0.29 to 0.19, P = 0.69), indicating stable kidney filtration capacity.
BUN: No significant effect (SMD = 0.11, 95% CI −0.15 to 0.37, P = 0.41).
Safety: No adverse effects on mortality or quality of life were reported.

Limitations

Heterogeneity: Variability in dosing protocols (3–20 g/day) and study durations may affect result consistency.
Population Scope: Findings apply only to healthy adults; studies on individuals with pre-existing kidney conditions were excluded.
Short-Term Focus: Most trials were ≤12 weeks, limiting insights into long-term safety.
Publication Bias: Potential underrepresentation of studies with negative results.
Mechanistic Gaps: The meta-analysis did not explore biochemical pathways linking creatine to renal stress.

Clinical Relevance

For healthy adults, creatine supplementation appears safe regarding renal function, as changes in serum creatinine likely reflect increased creatine turnover rather than kidney damage. However, individuals with compromised renal health should avoid creatine until further research clarifies risks. The study supports current evidence that creatine does not harm kidneys in normal populations but emphasizes the need for long-term monitoring and studies in at-risk groups. Users should prioritize hydration and consult healthcare providers if they have kidney concerns.

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