Association Between Renal Failure and Non-Prescription Cosmetic/Skin Care and Herbal Product Use: A Case-Control Study at UNTH, Enugu, Nigeria.

<ns5:p>Background Renal failure associated with exposure to potentially nephrotoxic substances in non-prescription cosmetic products, skincare preparations, and herbal remedies represents an emerging public health concern, particularly in low- and middle-income countries where regulation and safety monitoring remain limited. This study investigated the association between renal failure and exposure to cosmetic/skincare and herbal products among adults attending the University of Nigeria Teaching Hospital (UNTH), Enugu. Methods A hospital-based unmatched case–control study was conducted among 300 participants comprising 150 renal failure cases and 150 controls between September and December 2025. Cases included adults with confirmed chronic kidney disease stages 3–5, while controls had normal renal function. Bivariate and multivariable logistic regression analyses were performed, with statistical significance set at p &lt; 0.05. Results Renal failure cases were older than controls (54 ± 14 years vs 41 ± 15 years) and demonstrated lower educational attainment and income levels. Secondary cosmetic exposure was independently associated with renal failure (AOR = 3.40; 95% CI: 1.56–7.44; p = 0.002), while primary and secondary herbal exposure significantly increased the odds of disease (AOR = 4.00; 95% CI: 1.88–8.53; p &lt; 0.001 and AOR = 7.50; 95% CI: 3.26–17.27; p &lt; 0.001, respectively). Middle-aged and elderly individuals had higher odds of renal failure compared with younger adults (AOR = 4.46; 95% CI: 2.18–9.09; p &lt; 0.001). Diabetes mellitus (AOR = 14.35; p &lt; 0.001) and hypertension (AOR = 9.83; p &lt; 0.001) were the strongest independent clinical predictors. Conclusion Renal failure among adults attending UNTH was significantly associated with repeated herbal exposure, secondary cosmetic exposure, older age, hypertension, and diabetes mellitus. Strengthening regulation of cosmetic and herbal products, improving public awareness, and incorporating exposure history into renal assessment may support prevention and early detection of exposure-related kidney disease.</ns5:p>