Vitamin D toxicity, also called hypervitaminosis D, is a rare but potentially serious condition that occurs when you have excessive amounts of vitamin D in your body.
Vitamin D toxicity is usually caused by large doses of vitamin D supplements — not by diet or sun exposure. That's because your body regulates the amount of vitamin D produced by sun exposure, and even fortified foods don't contain large amounts of vitamin D.
The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause nausea and vomiting, weakness, and frequent urination. Vitamin D toxicity might progress to bone pain and kidney problems, such as the formation of calcium stones.
Treatment includes stopping vitamin D intake and restricting dietary calcium. Your doctor might also prescribe intravenous fluids and medications, such as corticosteroids or bisphosphonates.
Taking 60,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity. This level is many times higher than the U.S. Recommended Dietary Allowance (RDA) for most adults of 600 IU of vitamin D a day.
Doses higher than the RDA are sometimes used to treat medical problems such as vitamin D deficiency, but these are given only under the care of a doctor for a specified time frame. Blood levels should be monitored while someone is taking high doses of vitamin D.
As always, talk to your doctor before taking vitamin and mineral supplements.
Sign up for free, and stay up to date on research advancements, health tips and
current health topics, like COVID-19, plus expertise on managing health. To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health
information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.From Mayo Clinic to your inbox
March 22, 2022
- Dawson-Hughes B. Vitamin D deficiency in adults: Definition, clinical manifestations, and treatment. //www.uptodate.com/contents/search. Accessed March 20, 2020.
- Vitamin D. Office of Dietary Supplements. //ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Accessed March 20, 2020.
- Hypercalcemia. Hormone Health Network. //www.hormone.org/diseases-and-conditions/hypercalcemiaAccessed March 20, 2020.
- Vitamin D. Natural Medicines. //naturalmedicines.therapeuticresearch.com. Accessed March 20, 2020.
- Marcinowska-Suchowierska E, et al. Vitamin D toxicity — A clinical perspective. Frontiers in Endocrinology. 2018; doi:10.3389/fendo.2018.00550.
See more Expert Answers
See also
- Add flax to your baking
- Calcium
- Calcium for better bones
- Timing calcium supplements
- Calcium: Think outside the carton
- COVID-19 and vitamin D
- Can vitamins help prevent a heart attack?
- Can zinc supplements help treat hidradenitis suppurativa?
- Vitamin C and mood
- Fiber supplements
- Flaxseed best when ground
- Flaxseed for breakfast?
- Ground flaxseed
- Heartburn medicines and B-12 deficiency
- Herbal supplements
- Kratom and pregnancy: Not a safe mix
- Multivitamins for kids
- Nutrition: Does it come in a pill?
- Prebiotics, probiotics and your health
- Prenatal vitamins
- Probiotics and prebiotics
- Magnesium supplements
- Nutritional supplements
- Bromelain
- Curcumin
- Melatonin
- Vitamin C megadoses
- Vitamin C: An essential nutrient
- Vitamin D and MS: Any connection?
- Vitamin D deficiency
- Can having vitamin D deficiency cause high blood pressure?
- Vitamin D: Essential with calcium
- Vitamin D for babies
- Vitamins for MS: Do supplements make a difference?
.
- Taking too much vitamin D causes side effects like nausea, vomiting, weakness, and abdominal pain.
- The average adult should take no more than 4,000 international units of vitamin D daily.
- Vitamin D toxicity can be treated by stopping your supplement and avoiding vitamin D foods.
With about one in four Americans having low levels of vitamin D, it's no surprise that many people may consider a supplement, especially since very few foods contain the essential nutrient.
However, vitamin D supplements can come with side effects, especially if you take a high dose. That's because vitamin D is fat-soluble, meaning it can accumulate in the body's fat stores, possibly reaching toxic levels.
Here's how to tell if you're taking too much vitamin D and what side effects it can cause.
How much vitamin D is too much?
To avoid vitamin D toxicity, most adults should not take more than 4,000 IU/day of vitamin D supplements.
Therefore, if you're taking a vitamin D supplement you should have your blood levels checked every three to six months, according to Rajsree Nambudripad, MD, an integrative medicine specialist with Providence St. Jude Medical Center.
A healthy range for vitamin D blood concentration is between 60-80 ng/ml. So, you should stop taking any vitamin D supplements if blood levels exceed 100 ng/ml, which is when side effects may appear, says Nambudripad.
Side effects of vitamin D supplements
Vitamin D toxicity — which includes symptoms like confusion and abdominal pain — occurs when vitamin D reaches a concentration of at least 150 ng/ml in a person's blood.
Potential side effects of vitamin D toxicity include:
- Nausea
- Vomiting
- Abdominal pain
- Loss of appetite
- Weakness
- Excessive thirst and urination
- Kidney stones
- Confusion
- Pain
However, vitamin D toxicity is rare: "Generally you have to take a lot of vitamin D daily before you start to have toxic effects," says Erin R. McNeely, MD, an internist with Spectrum Health.
Excess vitamin D and calcium
Some of the side effects of vitamin D toxicity are due to and/or exacerbated by the fact too much vitamin D can cause hypercalcemia, or when blood levels of calcium are too high. That's because vitamin D facilitates the absorption of calcium.
If you experience any side effects of vitamin D toxicity, McNeely recommends stopping your supplement and avoiding calcium-rich foods like dairy, which can contribute to hypercalcemia. In most cases, that's all the treatment that is needed. Yet, some with hypercalcemia might also need IV hydration.
Once treatment is initiated, most people should start to feel better, but it may take awhile. For example, a 2011 case report of two people who took 1,000 times the recommended daily dose of vitamin D found that they had elevated calcium levels for a year, even after stopping supplementation and were experiencing symptoms. Though, after a year, their symptoms resolved and they had no long-term health consequences.
Insider's takeaway
Many people can benefit from vitamin D supplements, but it's a good idea to talk to your doctor or medical professional before taking high doses. They can help determine the right dose for you, and help you avoid side effects like nausea or confusion.
If you're taking more than 2,000 IU of vitamin D a day, be sure to get blood work every 3-6 months to make sure you're not building up too much vitamin D in your blood.
Kelly Burch is a New Hampshire-based freelance journalist writing about finances, health, family, and more. Her work has appeared in The Washington Post, The Chicago Tribune, and Forbes, among others. Follow her on Facebook or Twitter, and or learn more here.
Read more Read less