Taking supplements like NAD+, glutathione, and creatine has become popular for enhancing energy, supporting cellular health, and improving physical performance. However, many people share concerns about how these substances impact kidney function since kidneys are responsible for filtering waste and excess substances through urine. From my experience and research, while kidneys do filter out metabolic waste from these supplements, healthy kidneys can typically manage the process without damage when supplements are taken responsibly and in recommended doses. Staying well-hydrated is crucial because water helps the kidneys flush out these substances efficiently. Dehydration could add strain to the kidneys and create problems over time. It's also important to consider the quality and source of supplements. Pure, tested formulations reduce the risk of contaminants that might stress the kidneys. If you have pre-existing kidney issues or other health conditions, consulting a healthcare professional before starting any new supplement is essential. Injecting NAD+ and taking glutathione orally or intravenously have different absorption and processing pathways, so how your kidneys handle each might vary. Creatine, widely used in fitness, is known to increase creatinine levels, a kidney function marker, but this typically reflects supplementation rather than kidney damage. Incorporating kidney-friendly habits, such as balanced nutrition, limiting excessive protein intake, and avoiding harmful substances like excessive alcohol, supports your kidneys in managing extra supplement intake. Monitoring kidney health with routine check-ups can give peace of mind and early detection of any concerns. Overall, while there is some uncertainty as to how high doses or long-term use may affect kidney health, responsible use combined with healthy lifestyle choices usually keeps your kidneys safe and functioning well.