# Vitamin D Supplements: 4 Warning Signs You May Be Taking Too Much
Vitamin D plays an important role in bone health, muscle function, and calcium balance. Many people take supplements because they have low vitamin D levels or limited sun exposure.
But more is not always better.
Vitamin D toxicity is uncommon, but it can happen when someone takes **excessively high doses of vitamin D supplements**, usually over time. The main problem is that too much vitamin D can cause calcium levels in the blood to rise too high, a condition called **hypercalcemia**. ([Mayo Clinic][1])
That does **not** mean everyone taking vitamin D should stop. If you are taking a dose prescribed by your healthcare professional, follow their advice unless they tell you otherwise.
## 1. Nausea, Vomiting, or Loss of Appetite
One of the more common signs of excessive vitamin D is digestive upset.
Possible symptoms include:
* Nausea
* Vomiting
* Poor appetite
* Abdominal discomfort
These symptoms happen because high vitamin D levels can raise calcium in the blood. ([Mayo Clinic][1])
Of course, nausea is very common and has many causes. It becomes more relevant if you are taking high-dose vitamin D and also develop other symptoms on this list.
## 2. Unusual Weakness or Fatigue
Too much vitamin D can sometimes lead to muscle weakness, tiredness, or a general feeling of being unwell.
Possible symptoms include:
* Muscle weakness
* Low energy
* Feeling unusually tired
* Difficulty concentrating
The NIH lists muscle weakness and neuropsychiatric changes among possible effects of vitamin D toxicity-related hypercalcemia. ([ODs][2])
## 3. Excessive Thirst and Frequent Urination
High calcium levels can make you unusually thirsty and cause more frequent urination.
You may notice that you:
* Drink much more than usual
* Wake up at night to urinate
* Urinate larger amounts
* Feel dehydrated despite drinking fluids
These are recognized symptoms of vitamin D toxicity. ([ODs][2])
## 4. Kidney Stones or Kidney Problems
One of the more serious consequences of excessive vitamin D is kidney damage.
High calcium levels can contribute to:
* Kidney stones
* Kidney pain
* Reduced kidney function
* In severe cases, kidney failure
Mayo Clinic specifically notes that vitamin D toxicity can lead to kidney stones and kidney trouble. ([Mayo Clinic][1])
## How Much Vitamin D Is Too Much?
For most adults, the tolerable upper intake level is **4,000 IU (100 micrograms) per day** from all sources unless a healthcare professional recommends a higher dose for a specific reason. ([ODs][2])
That does not mean 4,001 IU is automatically toxic. Toxicity usually happens with much higher intake or inappropriate long-term supplementation.
