- Excessive thirst
- Frequent urination
- Nausea, vomiting, or constipation
- Confusion, unusual fatigue, or muscle weakness
Other possible signs can include:
- Kidney stones
- Bone pain
- Loss of appetite
- Irritability
- Dehydration
Why does this happen?
Vitamin D toxicity is usually caused by taking excessive supplements for an extended period, not by sunlight or normal dietary intake. Too much vitamin D can raise blood calcium levels (hypercalcemia), which causes the symptoms above.
Should everyone stop taking vitamin D?
No. Many people take vitamin D safely under medical guidance. The symptoms above are warning signs that warrant medical evaluation, not a reason for everyone to stop supplementation. In fact, vitamin D deficiency is also common and can cause fatigue, muscle weakness, bone pain, and other problems.
When to seek medical care
If you’re taking vitamin D supplements and experience symptoms such as:
- Severe thirst and urination
- Persistent nausea or vomiting
- Confusion
- Significant weakness
you should contact a healthcare professional promptly. They may order blood tests for vitamin D, calcium, and kidney function.
If you tell me:
- your age,
- the vitamin D dose you’re taking (e.g., 1,000 IU, 5,000 IU, 50,000 IU),
- how long you’ve been taking it,
- and any symptoms you’re experiencing,
I can help explain whether those symptoms are commonly associated with vitamin D excess, deficiency, or something else.

