Vitamin overdose: when health benefits turn into toxicity for kidneys and skinUncontrolled use of dietary supplements (BAS) can lead to toxic damage to the liver, kidneys, and cardiovascular system. High doses of catechins found in green tea extract can damage the liver, particularly if taken on an empty stomach. Selenium: Overdose can cause hair loss and severe nervous system damage. Special caution is required for children, pregnant and breastfeeding women, individuals with chronic kidney or liver disease, and patients preparing for surgery. Breastfeeding women should avoid all supplements without a doctor's prescription due to the risk of active substances entering breast milk.