Can You Take Too Much Vitamin D?

Quick Health Scoop

• Vitamin D helps support bone, teeth, muscle health; promotes a healthy immune system; and improves Calcium absorption.
• You can get Vitamin D from food, the sun, and dietary supplement
• Vitamin D is generally considered safe when taken in the recommended dosages.
• If taken in higher dosages, especially for lengthy periods, Vitamin D may cause undesirable side effects.

Is it possible to get too little or too much Vitamin D? You know this key nutrient promotes bone health, but can you overdo it when it comes to Vitamin D intake?

As a fat-soluble vitamin that emerged as a popular nutrient over the past decade, Vitamin D was discovered in the early 1900s as an anti-rickets compound. Thanks to mandatory U.S. fortification programs in the 1930s, Vitamin D has since been added to several food sources (especially dairy) and has long been considered a key vitamin essential for overall health. [1]

You might have heard that many people may have a low Vitamin D level. In fact, it’s estimated that 95% of U.S. adults don’t get enough Vitamin D from their diet alone. [2] Additionally, approximately 29% of U.S. adults are Vitamin D deficient.^‡

The Endocrine Society defines Vitamin D deficiency (VDD) as total blood serum 25-(OH)D levels of less than 50 nmol/L (<20 ng/mL) and Vitamin D insufficiency (VDS) as 52.5 to 72.5 nmol/L (21 to 29 nm/mL). [3] What does this mean in more simple terms? You’ll take a simple blood test that measures the amount of 25 hydroxyvitamin D (25-(OH)D) in your blood. That’s why it’s recommended to test your Vitamin D levels with your healthcare provider, as they will be able to determine if your levels are sufficient, insufficient or deficient from a blood test.

So, while low Vitamin D seems to be more common, as that’s nearly 95% of American adults, let’s take a look at the other end of the spectrum— excess Vitamin D.[2]

Can you take too much Vitamin D? Let’s first determine how much Vitamin D you might need.

How Much Vitamin D Do I Need?

It helps to understand the importance of Vitamin D and its role in the body. Among its many benefits, Vitamin D helps support bone, teeth, muscle and immune health, and it also helps improve Calcium absorption. [4,5]

The recommended daily intake of Vitamin D depends on a variety of factors, including age, skin color, how much sun exposure you get, your geographical location (certain northern latitudes get less sunlight), time of year, and whether or not you wear sunscreen.

If you’ve been diagnosed with a low Vitamin D level, you’ll probably require a higher Vitamin D dosage (at least temporarily) until your levels return to normal.

While you can get your Vitamin D daily dosage from three main sources—the sun, food, and vitamin supplements—this presents a few challenges. First, for people who live in northern latitudes, they may not get enough sun exposure, especially during the winter months. And, no matter where you live, experts advise wearing sunscreen outside to protect the skin from damaging UV rays. As for dietary sources of Vitamin D, only a few foods naturally contain this key nutrient, including fatty fish, cod liver oils, beef liver, cheese, egg yolks, and mushrooms. [7]. Some foods are also fortified with Vitamin D, such as milk, cereal, and orange juice. 

To help you increase your Vitamin D blood level, your healthcare provider may recommend Vitamin D supplementation at an increased dosage.

Specifically, how much Vitamin D should this be? [7]

What Is The Maximum Amount Of Vitamin D You Can Take Daily?

If you’ve got a Vitamin D deficiency^‡, your doctor may advise a high dose of Vitamin D intake—at least temporarily—to help restore your Vitamin D levels. For patients at risk of Vitamin D deficiency^‡ the Endocrine Society recommends the following dosages: [8]

• Birth to 12 months: 400-1,000 IU per day
• Children 1+ years: 600-1,000 IU per day
• Adults 19-70 years: 1,500-2,000 IU
• Adults 70+ years: 1,500-2,000 IU per day
• Pregnant and breastfeeding women 19-50 years: 1,500-2,000 IU per day

In addition, the Endocrine Society guidelines suggest that between 6,000 IU to 10,000 IU per day for children and adults aged 19 years and older may be needed to correct a Vitamin D deficiency. [8]

If you’re treating a Vitamin D deficiency^‡ with supplements, experts advise going back to your doctor for a blood test and have your level re-tested after supplementation.

Is It OK To Take Vitamin D Every Day?

Vitamin D comes in two main forms, whether it’s found in foods or dietary supplements: [9]

• Vitamin D2 (ergocalciferol) is found in some mushrooms
• Vitamin D3 (cholecalciferol) is found in beef liver, egg yolks, cheese, oily fish, and fish liver oil

Can you take Vitamin D every day? Yes! Research shows that Vitamin D3 is roughly 87% more potent in raising blood levels of Vitamin D and produces two to three times greater storage of Vitamin D in the body compared to Vitamin D2, thus making Vitamin D3 the body’s preferred form of Vitamin D. [10]

While it doesn’t really matter what time of day you take Vitamin D, many people take vitamins as part of their morning routine. Because Vitamin D is a fat-soluble vitamin, it’s absorbed more easily in the presence of dietary fat. So, at breakfast, consider eating some healthy fat such as avocado, eggs, full-fat dairy, or even oily fish with your supplement for optimal Vitamin D absorption.

Are There Any Side Effects When Taking Vitamin D?

If you’re taking Vitamin D in the recommended dosages, you should not experience any side effects, and it is generally considered safe. However, if you’re taking excessively high amounts of Vitamin D, especially for a long time, it may cause undesired side effects.

Bottom Line

Getting an adequate amount of Vitamin D is important to your well-being, and you can get this key nutrient from food, the sun, and dietary supplements. Vitamin D helps support bone, teeth, muscle and immune health. It also helps improve Calcium absorption. Taken in the recommended dosages, Vitamin D is generally considered safe. But if taken in higher dosages, especially for lengthy periods, Vitamin D can lead to some health issues. A doctor may advise Vitamin D supplementation to gap a deficiency, but patients should do this under the doctor’s supervision so he or she can continually monitor blood levels. †

Continue to check back on the Nature Made blog for the latest science-backed articles to help you take ownership of your health.

‡Approximately 29% of U.S. adults are Vitamin D deficient (<50 nmol/L). [11]

† These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.

References 

1. Mayo Clinic Proceedings. “Vitamin D for health: a global perspective.” July 2013. Accessed on August 5, 2022. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761874/

2. Reider CA, Chung RY, Devarshi PP, Grant RW, Hazels Mitmesser S. Inadequacy of Immune Health Nutrients: Intakes in US Adults, the 2005-2016 NHANES. Nutrients. 2020;12(6):1735. Published 2020 Jun 10. doi:10.3390/nu12061735.

3. Vitamin D Deficiency in Adults: Screening. Recommendation: Vitamin D Deficiency in Adults: Screening | United States Preventive Services Taskforce, US Preventive Services Taskforce, 13 Apr. 2021, https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/vitamin-d-deficiency-screening.

4. National Institutes of Health. “Vitamin D: Fact Sheet for Consumers.” June 2, 2022. Accessed on August 5, 2022. https://ods.od.nih.gov/factsheets/vitamind-healthprofessional/#h7

5. Oregon State University Linus Pauling Institute. “Vitamin D.” February 11, 2021. Accessed on August 8, 2022. https://lpi.oregonstate.edu/mic/vitamins/vitamin-D

6. “Vitamin D deficiency.” February 28, 2017. Accessed on August 8, 2022. https://medlineplus.gov/vitaminddeficiency.html

7. Harvard Health. “Vitamin D.” July 2022. Accessed on August 8, 2022. https://www.hsph.harvard.edu/nutritionsource/vitamin-d/

8. The Journal of Clinical Endocrinology & Metabolism. “Evaluation, Treatment, and Prevention of Vitamin D deficiency: An Endocrine Society Clinical Practice Guideline.” July 2011. Accessed on August 9, 2022. https://doi.org/10.1210/jc.2011-0385

9. National Institutes of Health. “Vitamin D: Fact Sheet For Professionals.” June 2, 2022. Accessed on August 9, 2022. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

10. The Journal of Clinical Endocrinology & Metabolism. “Vitamin D(3) is more potent than Vitamin D(2) in humans.” December 22, 2010. Accessed on August 9, 2022. https://pubmed.ncbi.nlm.nih.gov/21177785/

11. Liu X, Baylin A, Levy PD. Vitamin D deficiency and insufficiency among US adults: prevalence, predictors and clinical implications. Br J Nutr. 2018;119(8):928-936. doi:10.1017/S0007114518000491.