Excess vitamin D can lead to high calcium levels in the blood (hypercalcaemia). Symptoms may include:
1. Nausea, vomiting, or loss of appetite
Too much vitamin D can increase calcium levels, which may irritate the digestive system and cause:
- Nausea
- Vomiting
- Reduced appetite
- Stomach discomfort
2. Excessive thirst and frequent urination
High calcium levels can affect the kidneys and may cause:
- Increased thirst
- Needing to urinate more often
- Dehydration
3. Weakness, tiredness, or confusion
Severe vitamin D toxicity may cause:
- Unusual fatigue
- Muscle weakness
- Difficulty concentrating
- Confusion
4. Kidney-related symptoms
Very high vitamin D intake can contribute to kidney problems, which may involve:
- Flank or back pain
- Kidney stones
- Changes in urination
When should you seek medical advice?
Contact a healthcare professional if you develop concerning symptoms, especially if you:
- Take high-dose vitamin D supplements
- Have kidney disease
- Have conditions affecting calcium levels
- Take multiple supplements containing vitamin D or calcium
Don’t stop prescribed vitamin D without advice
If vitamin D was prescribed because of a deficiency or a medical condition, speak with your clinician before stopping it. They may recommend checking your vitamin D and calcium levels or adjusting your dose.
How much vitamin D is too much?
The safe amount depends on age, health status, and individual needs. Many people can maintain healthy levels with modest supplementation, while high-dose products should generally be used under medical guidance.
Bottom line: Vitamin D is beneficial when taken appropriately, but very high doses can be harmful. Symptoms such as persistent nausea, extreme thirst, frequent urination, unusual weakness, or confusion deserve medical attention—especially if you are taking large doses of supplements.
