Vitamin D supplements should not be taken without consulting a healthcare professional or outside their guidance. As vitamin D is a fat-soluble vitamin and not excreted through urine, its indiscriminate use can lead to excessively high blood levels. While optimal vitamin D levels are beneficial for body health, like any supplement, excessive intake can cause undesirable and potentially serious side effects. As a general guideline, a daily intake of more than 4000 units of vitamin D is not recommended for adults. Very high vitamin D levels can lead to calcium accumulation in soft tissues and organs, causing serious health problems. Therefore, if considering vitamin D supplementation, it is essential to consult an expert and have current vitamin D levels measured. Potential risks associated with excessive vitamin D use include: Tissue and joint calcification; Kidney stone formation and kidney damage; High blood pressure. Furthermore, excessive vitamin D intake can lead to vitamin D toxicity (hypervitaminosis D). Symptoms of toxicity can include dry mouth, headache, nausea, vomiting, and irregular heartbeat.