A pharmacist’s warning about vitamin D usually relates to the fact that, while vitamin D is important for bones, muscles, and immune function, too much can be harmful—especially when taken in high doses without medical guidance.
Things to know before taking vitamin D supplements
- Avoid excessive doses
- Vitamin D is fat-soluble, meaning the body stores it.
- Very high doses over time can lead to vitamin D toxicity, which may cause high calcium levels in the blood.
- Watch for signs of too much vitamin D
Possible symptoms include:
- Nausea or vomiting
- Constipation
- Excessive thirst
- Frequent urination
- Weakness or fatigue
- Confusion
- Kidney stones or kidney problems
- People who should ask a healthcare professional first
Extra caution is needed for people with:
- Kidney disease
- A history of kidney stones
- High calcium levels
- Certain thyroid or parathyroid disorders
- Conditions that affect calcium metabolism
- Check medication interactions
Vitamin D can interact with some medicines, including certain:
- Diuretics (“water pills”)
- Steroids
- Heart medications such as some digoxin-containing treatments
- More is not always better
Many people can get enough vitamin D through a combination of sunlight exposure, diet, and appropriately dosed supplements. A blood test can help determine whether supplementation is needed.
If you take vitamin D, it helps to know the dose (for example, 1,000 IU, 2,000 IU, 5,000 IU, or higher), how often you take it, and any other medicines or supplements you use.
