Vitamin D Overdose: Is It Possible?

What is vitamin D overdose?

Ingesting large amounts of vitamin D beyond recommended dosages can result in a vitamin D overdose (also called vitamin D toxicity). You can get vitamin D from taking it as a supplement, through foods you eat, or from sun exposure.

It is unlikely that vitamin D from food or sunlight would cause an overdose, so typically, it would be caused by taking too much vitamin D supplement.

The dose at which vitamin D becomes dangerous needs to be clarified and likely varies from person to person. According to Mayo Clinic, taking 60,000 international units (IU) of vitamin D daily for months on end can lead to toxicity. For this reason, people should be wary of taking megadoses of vitamin D, sometimes featured in trendy fad diets.

Doctors prescribe vitamin D supplements at high doses for conditions like malabsorption, renal osteodystrophy, osteoporosis, and psoriasis. If your doctor has prescribed a vitamin D supplement, always adhere to the dosage recommendations at the correct frequency. Vitamin D overdose can occur when patients accidentally ingest too much or more often than prescribed.

Vitamin D overdose symptoms

Ingesting too much vitamin D can cause excess calcium buildup within your body, resulting in symptoms that range in severity depending on how much vitamin D you have taken and how much calcium has built up in the body.¹

Common symptoms of vitamin D overdose include:

• Nausea
• Vomiting
• Weakness
• Fatigue
• Confusion

• Constipation
• Decreased appetite
• Dehydration
• Kidney stones

When vitamin D levels get abnormally high, severe side effects can occur, such as:

• Kidney failure
• Heartbeat irregularities

• Death

Vitamin D overdose symptoms can vary by age group. For example, infants and young children will show different symptoms than adults. Infants who are experiencing a vitamin D overdose may show any of the following signs:

• Lack of appetite
• Inconsolable crying

• Lethargy or drowsiness

Toddlers experiencing vitamin D overdose may show the following signs:

• Vomiting
• Irritability

• Constipation

Diagnosis and treatment

To diagnose vitamin D deficiency, your doctor begins with a physical exam and will ask what symptoms you may have experienced. They determine any potential vitamin D prescriptions and the amount you take daily. You may have to have your blood drawn to look at your blood’s vitamin D, phosphate, and calcium levels, and your doctor may order an x-ray to examine your bones.

Treating vitamin D overdose usually involves discontinuing any vitamin D supplements and limiting calcium intake from food. You may also require IV fluids or medications such as steroids and bisphosphonates. Most people with vitamin D deficiency recover without experiencing severe complications. Still, it can become dangerous if left untreated, so it is essential to seek immediate treatment if you are experiencing vitamin D toxicity.

Vitamin D overdose prevention

You should only take vitamin D supplements as your doctor prescribes to prevent vitamin D overdose. The recommended daily vitamin D requirement for adults ages 1 to 70 is 600 international units (IU).

If your doctor has prescribed a higher vitamin D dosage, you should ensure that your vitamin D levels are monitored through blood work regularly. Additionally, purchasing vitamin D supplements from a reliable source is crucial.

The FDA does not regulate dietary supplements like vitamin D; therefore, they are not always reliably tested for the concentrations they contain. For this reason, someone may be under the impression they are taking a specific dose of vitamin D but are taking more or less than they believe if these supplements have not been quality tested.

Last words

Vitamin D offers the body a variety of health benefits, but too much can prove problematic. Vitamin D overdose is certainly possible, so you should always pay attention to the amount you are taking and ensure that you have regular blood level testing if you are supplementing vitamin D. Purchase vitamin D from a reputable source and always check to see how much you are taking and ensure that you dose it correctly to prevent an overdose.