8 Signs You May Be Getting Too Much Vitamin D
Medically reviewed by Rosanna Sutherby, PharmD on October 16, 2023. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
Table of contents
- The Importance of Vitamin D
- Signs and Symptoms of Too Much Vitamin D
- What Can Be Done About Vitamin D Toxicity?
- How Much Vitamin D Do You Need?
- Ways to Get Vitamin D
- Benefits of Testing Your Vitamin D Levels
Vitamin D is a key nutrient because it helps your body absorb dietary calcium so you can have strong, healthy bones. [1] That’s why it’s important to get enough of it. But it’s also possible to get too much vitamin D—referred to as vitamin D toxicity. While this is rare, it can still be useful to know the common signs of too much vitamin D—particularly if you take vitamin D supplements regularly. [2]
Here, we’ll discuss some vitamin D toxicity symptoms, so read on (and if you’d like to check your vitamin D levels from the comfort of home, consider trying our vitamin D test kit).
The Importance of Vitamin D
Vitamin D is a fat-soluble vitamin. This means the intestine can absorb the vitamin when fat is present.3 Fat-soluble vitamins are then distributed throughout the body via the bloodstream. Vitamin D, specifically, supports calcium absorption in the gut and bone mineralization to prevent brittle or misshapen bones. [4]
Vitamin D can also help to [4]:
- Reduce inflammation
- Regulate cell growth
- Support immune function
- Metabolize glucose
Often, vitamin D is referred to as “the sunshine vitamin” because UV rays can promote vitamin D production within your body. When UV rays hit your skin, a chemical reaction occurs to create vitamin D3.
You can also get vitamin D through your diet. However, there are very few levels of the vitamin in the foods you eat. Rather, vitamin D and vitamin D3 supplements are the most effective way to increase your dietary intake.
Vitamin D supplementation is particularly beneficial for people susceptible to vitamin D deficiency – those who live in areas with low sunlight or people with more melanin, which protects the skin from the sun’s rays. Spending limited time outdoors, covering your skin, and using sunscreen can also significantly decrease your vitamin D levels. [3]
Signs and Symptoms of Too Much Vitamin D
This condition can cause constipation, where bowel movements become infrequent and difficult. To prevent this, it's essential to maintain a balanced approach to vitamin D supplementation and consult a healthcare professional to avoid issues with vitamins that cause constipation. This emphasizes the importance of expert guidance when addressing vitamin D deficiencies for optimal levels without side effects.
However, in the case of hypervitaminosis D, when there is too much vitamin D in the body, calcium levels can rise—a condition called hypercalcemia. [2]
Hypercalcemia is not life-threatening and often asymptomatic, meaning some people with the condition won’t experience any symptoms. However, that isn’t always the case. [2]
Symptoms of too much vitamin D in your bloodstream include [2]:
- Nausea
- Vomiting
- Weakness
- Vitamin D headache
- Frequent urination
- Painful muscles
- Kidney damage and kidney stones
- High blood pressure
What Can Be Done About Vitamin D Toxicity?
If you believe you’re experiencing symptoms of vitamin D toxicity, visit your healthcare provider. To diagnose the condition, they’ll likely administer blood tests to determine vitamin D and calcium levels in your body.
If you’re experiencing severe symptoms, such as arrhythmia and mental confusion, they may also test the function of your kidneys to determine whether kidney failure is present. [2]
If vitamin D toxicity occurs, your healthcare provider may suggest restricting your dietary calcium intake. Treatment may also include discontinuing the use of any vitamin D supplement—at least temporarily. If you’re dehydrated, they may also administer IV fluids. [2]
If your blood contains extremely high levels of vitamin D, your healthcare provider can also prescribe medications like corticosteroids and bisphosphonates to prevent your bones from absorbing the vitamin. [2]
If you’re wondering, “Can you overdose on vitamin D?” fortunately, the answer is no. Although you won’t experience vitamin D overdose, reaching out to your healthcare provider if you’re experiencing symptoms is important to protecting your overall health.
How Much Vitamin D Do You Need?
Now that you know about too much vitamin D, you may be wondering, “How much vitamin D do I need?” The recommended dietary allowance (RDA) for people in different age groups is shown below.
The Office of Dietary Supplements at The National Institute of Health highlights various RDAs, as developed by the National Academies of Sciences, Engineering, and Medicine (NASEM). [4]
Based on a number of factors, however, your healthcare provider may suggest doses that are higher or lower than what’s listed—so consider asking your provider for their recommendation. [4]
Note that the amount of vitamin D in foods and a vitamin D supplement is usually expressed in terms of International Units (IU), so “IU/day” refers to “International Units per day.” Recommended dietary allowance (IU/day) for vitamin D followed by the upper intake level are as follows [4]:
Infants 0-12 months
Male: 400 IU/day for adequate intake
Female: 400 IU/day for adequate intake
Children 1–13 years
Male: 600 IU/day for adequate intake
Female: 600 IU/day for adequate intake
Teens 14–18 years
Male: 600 IU/day for adequate intake
Female: 600 IU/day for adequate intake
Female (pregnant or lactating): 600 IU/day for adequate intake
Adults 19–50 years
Male: 600 IU/day for adequate intake
Female: 600 IU/day for adequate intake
Female (pregnant or lactating): 600 IU/day for adequate intake
Adults 51–70 years
Male: 600 IU/day for adequate intake
Female: 600 IU/day for adequate intake
Adults over 70 years
Male: 800 IU/day for adequate intake
Female: 800 IU/day for adequate intake
In some cases, healthcare providers may prescribe higher doses to treat a vitamin D deficiency, though these numbers provide a good guideline. Of course, talk with your healthcare provider to learn what amount of vitamin D intake they recommend for you.
How Can You Measure Your Vitamin D Intake in International Units (IU)?
If you’re taking a vitamin D supplement, the amount of vitamin D will likely be listed on the supplement's nutritional label, either in International Units or micrograms (2.5 micrograms = 100 IU). Micrograms may be abbreviated as "mcg."4
Finally, you can also get a sense of the vitamin D content of various kinds of food by visiting the National Institutes of Health's resource on vitamin D (see Table 3).
Ways to Get Vitamin D
You can get vitamin D from sunlight exposure, dietary sources, and supplements. [4] Getting ample vitamin D through sun exposure can be straightforward, but you do need to make sure you don’t get sunburned (by limiting how much time you spend out in the sun, for example). [4]
High vitamin D foods include beef liver, egg yolks, and fatty fish like salmon and tuna. There are also many fortified foods, like milk and dairy products, that provide your body with vitamin D. [4]
Signs of Inadequate Vitamin D Intake
Along with knowing the signs of too much vitamin D, it’s a good idea to know the signs of inadequate vitamin D intake.
Inadequate vitamin D intake can result in signs and symptoms like [5]:
- Fatigue
- Depression
- Weakness
- Joint, bone, and muscle pain
Studies have even shown that low vitamin D levels may be connected to higher risks of heart disease, diabetes, cancer, mood disorders, and dementia. Additionally, low vitamin D levels may increase the risk of bone fractures in older adults. [3]
Benefits of Testing Your Vitamin D Levels
If you’re experiencing any of the symptoms of vitamin D insufficiency noted above—or are experiencing too much vitamin D side effects—your intake may be imbalanced in some way.
Testing your vitamin D levels can help you determine if your levels are normal or if you may need to make adjustments and have a discussion with your healthcare provider. Our at-home vitamin D test kit lets you check your levels easily—it only requires a simple finger prick blood sample, and shipping is free both ways. Plus, you’ll get to conveniently view your results on our secure, online platform just days after the lab receives your sample.
References
- Vitamin D. NIH. Published November 8, 2022. URL. Accessed October 10, 2023.
- Vitamin D Toxicity (Hypervitaminosis D). Cleveland Clinic. Published February 21, 2023. URL. Accessed October 10, 2023.
- Vitamin D. Harvard T.H. Chan School of Public Health. Published March 2023. URL. Accessed October 10, 2023.
- Vitamin D. NIH. Published September 18, 2023. URL. Accessed October 10, 2023.
- Sizar O, et al. Vitamin D Deficiency. StatPearls. Published July 18, 2023. URL. Accessed October 10, 2023.