This study investigated the efficacy of intravenous amino acids in reducing acute kidney injury (AKI) in patients undergoing cardiac surgery. A total of 3511 patients were randomized to receive either amino acids or a placebo. Results showed a significant reduction in AKI occurrence in the amino acid group (26.9%) compared to the placebo group (31.7%), with a relative risk of 0.85. The severity of AKI and the need for kidney-replacement therapy were also lower in the amino acid group. No major differences in other secondary outcomes or adverse events were observed.