Side effects of excess vitamin D

close up of a woman's hand holding vitamin D supplements


In this article:

  • Vitamin D helps you keep your bones and immune system strong.

  • Experts recommend no more than 4,000 IU of vitamin D daily.

  • If you’re exhibiting signs of excessive vitamin D, talk to your Swedish physician.

Vitamin D plays a leading role in keeping you healthy. It helps your body absorb calcium and phosphorous, which is vital for maintaining strong bones and teeth. Vitamin D keeps your cells functioning correctly and helps your muscles, nerve and immune systems perform at their best.

Vitamin D deficiency has serious consequences. Without enough, you could end up with soft bones, reduced bone mass and an increased risk of bone fractures. It’s no surprise that so many people are turning to supplements to ensure they’re getting the vitamin D they need.

Supplements are an excellent way to add to the vitamin D you get from sunlight and diet — many doctors recommend taking a daily dose. Most experts advise taking no more than 4,000 IU of vitamin D a day. Exceeding that on a regular basis, even if you are vitamin D deficient, could produce toxic levels that damage your health.

Most experts advise taking no more than 4,000 IU of vitamin D a day. Exceeding that on a regular basis, even if you are Vitamin D deficient, could produce toxic levels that damage your health.

Signs you’re taking too much vitamin D

It’s fairly rare to exceed your vitamin D needs, but how do you know when it happens? If you regularly experience two or more of the symptoms listed below, it may be time to talk to your doctor about testing your vitamin D levels and adjusting your daily supplement dose.

  • Change in your skin tone
  • Constant headache
  • Constipation
  • Excessive fatigue
  • Increased thirst
  • Loss of appetite
  • Muscle weakness
  • Nausea and vomiting

Does it matter?

If you take supplements, be aware that more does not always equal better. When you have more vitamin D than you need, it can have a negative effect on your health. You may experience one or more of the following conditions.

1. High calcium levels

Vitamin D improves your body’s ability to absorb calcium. With too much vitamin D, your blood calcium levels can rise to dangerous levels, causing nausea, vomiting and stomach pain. You may also experience excessive thirst and need to urinate more frequently.

2. Bone loss

If excess vitamin D causes your blood to have too much calcium, it can lead to low vitamin K levels. This affects your body’s ability to bind with calcium and use it effectively. Brittle bones, bone pain, and bone loss are all possible results.

3. Organ damage

Excess calcium can bind with phosphates in your blood and form crystals that collect in your body’s soft tissues. In severe cases, it can lead to permanent kidney and lung damage.

4. Dehydration

When you have too much vitamin D, your kidneys have trouble concentrating your urine. When this happens, the extra urine they produce will have you spending an extreme amount of time going back and forth to the bathroom. If that goes on too long, you’ll lose too much fluid and electrolytes and could be prone to dehydration.

5. Heart issues

Too much calcium in your blood affects your heart’s ability to function as it should. Irregular heartbeats, chest pain, dizziness and high blood pressure may be the final outcome if it is not corrected.

Find a doctor

If you have questions about your vitamin D intake, contact the primary care department at Swedish. We can accommodate both in-person and virtual visits.

Whether you require an in-person visit or want to consult a doctor virtually, you have options. Swedish Virtual Care connects you face-to-face with a nurse practitioner who can review your symptoms, provide instruction and follow up as needed. If you need to find a doctor, you can use our provider directory.

Join our Patient and Family Advisory Council.

Additional resources 

No bones about it: Prevention is key with osteoporosis

Calcium and vitamin D: Important at Any Age

Vitamin D

This information is not intended as a substitute for professional medical care. Always follow your health care professional's instructions.

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About the Author

Our philosophy for well being is looking at the holistic human experience. As such, the Swedish Wellness & Lifestyle Team is committed to shining a light on health-related topics that help you live your healthiest life. From nutrition to mindfulness to annual screenings, our team offers clinically-backed advice and tips to help you and your loved ones live life to the fullest.

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