Could You Have Too Much Vitamin D?

Vitamin D plays an important role in maintaining health. However, too much can be harmful and cause symptoms like stomach discomfort, unusual mental symptoms, or kidney problems. It is a fat-soluble vitamin that can build up in your tissues if you take too many vitamin D supplements.

A blood test can help determine if you have too much vitamin D, known as vitamin D toxicity. This article covers the signs and symptoms of too much vitamin D, the side effects of taking vitamin D supplements, and more.

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Signs and Symptoms of Taking Too Much Vitamin D

Vitamin D is required to maintain health. It also acts as a hormone, contributing to many processes in the body. Because it is fat-soluble, vitamin D is stored in the body’s fatty tissue and the liver.

While getting enough vitamin D to support your health is important, too much can be a problem. Below are the signs and symptoms of taking too much vitamin D, also known as hypervitaminosis D.

Elevated Vitamin D Blood Levels

A healthcare provider can order a blood test to check your vitamin D level. High serum (blood) levels of vitamin D are defined as greater than 100 nanograms per milliliter (ng/mL), with adverse effects seen particularly at greater than 150 ng/mL.

Optimal blood vitamin D levels are generally between 30 ng/mL and 60 ng/mL. Experts do not believe that excessive sun exposure results in vitamin D toxicity due to how sunlight activates different forms of vitamin D in the skin.

Vitamin D toxicity is rare, and most cases of vitamin D toxicity are caused by inappropriate supplement dosing and prescription errors.

For example, a review of case reports of vitamin D toxicity found that many resulted in the overcorrection of vitamin D deficiency. In these cases, people presented with vitamin D levels well above optimal, ranging between 150 to 1,220 ng/mL.

It’s important to note that people with low vitamin D blood levels may need higher supplemental doses to meet and maintain an optimal vitamin D status. However, a healthcare provider should monitor this higher intake closely, checking blood vitamin D levels regularly to ensure they do not rise to toxic levels.

Consult a healthcare provider before taking vitamin D supplements. They can help guide you on the appropriate dosage you should take.

Elevated Calcium Levels

One of the main roles of vitamin D is to increase calcium absorption in the gastrointestinal (GI) tract. Because of this, vitamin D toxicity also results in hypercalcemia (blood calcium levels above normal) and hypercalciuria (excess calcium in the urine).

If you have too much vitamin D in your blood, your blood calcium levels should also be assessed. Normal blood calcium levels are 8.4 to 10.2 milligrams per deciliter (mg/dL). Hypercalcemia is defined as blood calcium levels greater than 10.5 mg/dL.

Most of the symptoms seen with vitamin D toxicity are related to the associated hypercalcemia, which can be life-threatening.

These symptoms include:

• Nausea
• Vomiting
• Muscle weakness
• Neuropsychiatric disturbances
• Pain
• Loss of appetite
• Dehydration
• Needing to urinate more frequently
• Excessive thirst
• Kidney stones

In general, research shows that vitamin D-associated hypercalcemia only happens when extremely large doses of vitamin D, such as over 10,000 International Units (IU) per day, are taken over time.

Seek medical attention if you are experiencing symptoms related to vitamin D toxicity or hypercalcemia.

Gastrointestinal Symptoms

The most common side effects of too much vitamin D are related to hypercalcemia. This leads to GI-related symptoms, such as:

• Nausea
• Vomiting
• Loss of appetite
• Constipation

Altered Mental Health

Aside from the physical symptoms associated with too much vitamin D and related hypercalcemia, there may also be symptoms related to mental health. These include:

• Confusion
• Apathy (lack of interest, enthusiasm, or concern)
• Depression
• Irritability
• Hallucinations
• Psychosis
• Stupor (in extreme cases)
• Coma (in extreme cases)

For example, one case study reported hypercalcemia in a 64-year-old person due to excess vitamin D supplementation of 200,000 IU daily. This resulted in altered mental status, along with other physical symptoms related to hypercalcemia.

The person was hospitalized and continued to be agitated and confused for 10 days, with blood calcium levels returning to normal after 18 days.

Kidney Complications

Too much vitamin D and the related hypercalcemia can lead to kidney complications, such as decreased kidney function, kidney injury, renal failure, and kidney stones. People with kidney disease also need to prevent taking too much vitamin D, as it can lead to serious kidney complications.

Numerous case studies have reported kidney complications related to excess vitamin D intake.

For example, a 65-year-old male took injections of 50,000 IU of vitamin D per week for one year. Upon admission to the hospital, he had acute (short-term) kidney injury, among other symptoms. Prompt treatment improved symptoms and avoided further damage to his kidneys.

Another case study involved a 54-year-old male who presented with a suspected kidney injury. Upon investigation, it was found that he was taking 8,000–12,000 IU of vitamin D drops daily for roughly 2.5 years.

Both his blood vitamin D and calcium levels were very high. After undergoing treatment for nearly one year, his calcium and vitamin D levels returned to normal. However, he was left with stage 3B chronic kidney disease.

How Much Vitamin D to Take Per Day

The recommended dietary allowance (RDA) for vitamin D for healthy people ages 1 to 70 years is 600 IU, or 15 micrograms (mcg), per day. It’s recommended for people over age 70 to get 800 IU, or 20 mcg daily.

This amount includes vitamin D you get from food, as well as dietary supplements.

Vitamin D is found naturally in a few foods, such as fatty fish (salmon, tuna trout), beef liver, egg yolks, and mushrooms treated with ultraviolet (UV) light. Vitamin D is added, or fortified, to some foods to increase intake in American diets. Commonly fortified foods include milk and breakfast cereals.

If your vitamin D levels are low, talk with a healthcare provider to determine how much vitamin D you should take to help bring it to optimal status.

Signs of a Vitamin D Deficiency

Most people in the United States do not consume the recommended amount of vitamin D.

People can develop a vitamin D deficiency for various reasons, such as when their intake is below the recommended amount, they do not have adequate sun exposure, their body cannot convert vitamin D to its active form, or they have trouble absorbing it from the GI tract.

In children, severe vitamin D deficiency leads to rickets, a disease characterized by bowed legs due to softening of the bones. In the United States, rickets is most common among breastfed Black infants and children.

Other populations at risk of developing vitamin D deficiency are older adults, people with limited sun exposure, people with dark skin, people with conditions that limit fat absorption, and people with obesity or who have undergone gastric bypass surgery.

Other signs of severe vitamin D deficiency in children include failure to thrive, developmental delay, and dental abnormalities. Also, vitamin D deficiency can result in hypocalcemia (low blood calcium levels), leading to cardiomyopathy (a disorder affecting the heart muscle), hypocalcemic seizures, and tetanic (muscle) spasms.

In adults, vitamin D deficiency can lead to osteomalacia (loss of bone minerals) and osteoporosis (porous, thinning bones). Symptoms include:

• Weak bones
• Bone pain
• Muscle weakness
• Bone deformities
• Dental abnormalities

Testing Vitamin D Levels

Vitamin D status is tested by drawing blood to measure 25 hydroxyvitamin D, or 25(OH)D, in your blood. A healthcare technician or nurse will collect a small amount of blood from your arm into a test tube or vial using a small needle. The process usually takes less than five minutes.

The 25(OH)D level is the most accurate way to measure how much vitamin D is in the blood. It reflects vitamin D produced endogenously (inside the body) and obtained from diet and supplements.

Possible Vitamin D Side Effects

Generally, eating foods with vitamin D in them is well tolerated, and there are no known side effects from vitamin D produced as a result of sunlight exposure.

Supplemental vitamin D3 may cause some side effects, such as:

• Loss of appetite
• Weight loss
• Nausea
• Vomiting
• Constipation

Contact a healthcare provider if you experience these or any unusual symptoms while taking vitamin D supplements.

Summary

Vitamin D is a fat-soluble vitamin and hormone that is involved in many processes in the body to support and maintain good health. One of the main roles of vitamin D is to promote calcium absorption in the gut to help maintain normal blood calcium levels.

You cannot get too much vitamin D from diet or sunlight exposure, but you can get too much from supplements. Too much vitamin D can cause health problems, including high blood calcium levels, kidney problems, and gastrointestinal problems such as nausea, vomiting, loss of appetite, and constipation.

Too much vitamin D can also lead to altered mental health, such as confusion, apathy, depression, irritability, hallucinations, and psychosis. Vitamin D status is measured using a blood test.

Most people in the United States do not consume the recommended amount of vitamin D. Signs of vitamin D deficiency include weak bones, bone pain, muscle weakness, bone deformities, and dental abnormalities.

Possible side effects of supplemental vitamin D3 include loss of appetite, weight loss, nausea, vomiting, and constipation.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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By Brittany Poulson, MDA, RDN, CD, CDCES
Brittany Poulson, MDA, RDN, CDCES, is a registered dietitian and certified diabetes care and education specialist.

Vitamin D Deficiency

Vitamin D deficiency is a common vitamin deficiency that causes issues with your bones and muscles. It most commonly affects people over the age of 65 and people who have darker skin. It’s preventable and treatable.

Overview

What is vitamin D deficiency?

Vitamin D deficiency means you don’t have enough vitamin D in your body. It primarily causes issues with your bones and muscles.

Vitamin D is an essential vitamin that your body uses for normal bone development and maintenance. Vitamin D also plays a role in your nervous system, musculoskeletal system and immune system.

You can get vitamin D in a variety of ways, including:

• Sun exposure on your skin (however, people with darker skin and older people may not get enough vitamin D through sunlight. Your geographical location may also prevent adequate vitamin D exposure through sunlight).
• Through the food you eat.
• Through nutritional supplements.

Despite all these methods to get vitamin D, vitamin D deficiency is a common worldwide problem.

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Why is vitamin D so important?

Vitamin D is one of many vitamins your body needs to stay healthy. It plays a crucial role in maintaining the balance of calcium in your blood and bones and in building and maintaining bones.

More specifically, you need vitamin D so your body can use calcium and phosphorus to build bones and support healthy tissues.

With chronic and/or severe vitamin D deficiency, a decline in calcium and phosphorus absorption by your intestines leads to hypocalcemia (low calcium levels in your blood). This leads to secondary hyperparathyroidism (overactive parathyroid glands attempting to keep blood calcium levels normal).

Both hypocalcemia and hyperparathyroidism, if severe, can cause symptoms, including muscle weakness and cramps, fatigue and depression.

To try to balance calcium levels in your blood (via secondary hyperparathyroidism), your body takes calcium from your bones, which leads to accelerated bone demineralization (when a bone breaks down faster than it can reform).

This can further result in osteomalacia (soft bones) in adults and rickets in children.

Osteomalacia and osteoporosis put you at an increased risk for bone fractures. Rickets is the same as osteomalacia, but it only affects children. Since a child’s bones are still growing, demineralization causes bowed or bent bones.

Who does vitamin D deficiency affect?

Anyone can have vitamin D deficiency, including infants, children and adults.

Vitamin D deficiency may be more common in people with higher skin melanin content (darker skin) and who wear clothing with extensive skin coverage, particularly in Middle Eastern countries.

How common is vitamin D deficiency?

Vitamin D deficiency is a common global issue. About 1 billion people worldwide have vitamin D deficiency, while 50% of the population has vitamin D insufficiency.

Approximately 35% of adults in the United States have vitamin D deficiency.

Symptoms and Causes

Anyone can have vitamin D deficiency, including infants, children and adults.

What are the signs and symptoms of vitamin D deficiency?

Severe lack of vitamin D in children causes rickets. Symptoms of rickets include:

• Incorrect growth patterns due to bowed or bent bones.
• Muscle weakness.
• Bone pain.
• Deformities in joints.

This is very rare. Children with a mild vitamin deficiency may just have weak, sore and/or painful muscles.

Lack of vitamin D isn’t quite as obvious in adults. Signs and symptoms might include:

• Fatigue.
• Bone pain.
• Muscle weakness, muscle aches or muscle cramps.
• Mood changes, like depression.

However, you may have no signs or symptoms of vitamin D deficiency.

What causes vitamin D deficiency?

In general, the two main causes of vitamin D deficiency are:

• Not getting enough vitamin D in your diet and/or through sunlight.
• Your body isn’t properly absorbing or using vitamin D.

There are several specific causes of vitamin D deficiency, including:

• Certain medical conditions.
• Weight loss-surgeries.
• Certain medications.

Several different biological and environmental factors can also put you at a greater risk of developing vitamin D deficiency, such as older age and the amount of melanin (pigment) in your skin.

Medical conditions that can cause vitamin D deficiency

Medical conditions that can cause vitamin D deficiency include:

• Cystic fibrosis, Crohn’s diseaseand celiac disease: These conditions can prevent your intestines from adequately absorbing enough vitamin D through supplements, especially if the condition is untreated.
• Obesity: A body mass index greater than 30 is associated with lower vitamin D levels. Fat cells keep vitamin D isolated so that it’s not released. Obesity often requires taking larger doses of vitamin D supplements to reach and maintain normal levels.
• Kidney disease and liver disease: These conditions reduce the amount of certain enzymes (hepatic enzyme 25–hydroxylase from your liver and 1-alpha-hydroxylase from your kidneys) your body needs to change vitamin D to a form it can use. A lack of either of these enzymes leads to an inadequate level of active vitamin D in your body.

Weight-loss surgeries and vitamin D deficiency

Weight-loss surgeries that reduce the size of your stomach and/or bypass part of your small intestines, such as gastric bypass surgery, make it difficult for your body to absorb sufficient quantities of certain nutrients, vitamins and minerals.

If you’ve had weight-loss surgery, it’s important to see your healthcare provider regularly so they can monitor your vitamin D levels and other nutrient levels. You’ll likely need to take vitamin D supplements and other supplements throughout your life.

Medications that can cause vitamin D deficiency

Certain medications can lower vitamin D levels, including:

• Laxatives.
• Steroids (such as prednisone).
• Cholesterol-lowering drugs (such as cholestyramine and colestipol).
• Seizure-preventing drugs (such as phenobarbital and phenytoin).
• Rifampin (a tuberculosis drug).
• Orlistat (a weight-loss drug).

Always tell your healthcare provider about your medications and any supplements and/or herbs you take.

Diagnosis and Tests

How is vitamin D deficiency diagnosed?

Healthcare providers don’t usually order routine checks of vitamin D levels, but they might need to check your levels if you have certain medical conditions or risk factors for vitamin D deficiency and/or have symptoms of it.

Your provider can order a blood test to measure your levels of vitamin D. There are two types of tests that they might order, but the most common is the 25-hydroxyvitamin D, known as 25(OH)D for short.

Management and Treatment

How is vitamin D deficiency treated?

The goals of treatment and prevention for vitamin D deficiency are the same: to reach and then maintain an adequate vitamin D level in your body.

While you might consider eating more foods containing vitamin D and getting more sunlight, your healthcare provider will likely recommend taking vitamin D supplements.

Vitamin D comes in two forms: D2 and D3. D2 (ergocalciferol) comes from plants. D3 (cholecalciferol) comes from animals. You need a prescription to get D2. D3, however, is available over the counter. Your body more easily absorbs D3 than D2.

Work with your healthcare provider to find out if you need a vitamin supplement and how much to take, if needed.

Prevention

Who is most at risk for vitamin D deficiency?

Aside from medical conditions that can lead to vitamin D deficiency, biological and environmental factors that put someone at an increased risk of vitamin D deficiency include:

• Age: Your skin’s ability to make vitamin D decreases with age, so people over the age of 65 years are especially at risk for vitamin D deficiency. Infants are also at risk of not receiving enough vitamin D. This is especially true for infants who are only fed breast milk, as it contains only a small amount of vitamin D.
• Skin color: It’s more difficult for dark-colored skin to make vitamin D from sunlight than light-colored skin, so people with darker skin are at a higher risk for vitamin D deficiency.
• Mobility: People who are homebound or rarely go outside (for example, people in nursing homes and other facilities) aren’t able to use sun exposure as a source of vitamin D. Thus, they’re at a higher risk for vitamin D deficiency.

How can I prevent vitamin D deficiency?

The best way to prevent vitamin D deficiency is to ensure you’re getting enough vitamin D in your diet and/or through sun exposure. But be careful about being in the sun for too long without sunscreen. Excessive sun exposure puts you at an increased risk for skin cancer.

The amount of vitamin D you need each day depends on your age. The average daily recommended amounts are listed below in micrograms (mcg) and International Units (IU).

There are a few foods that naturally have some vitamin D, including:

• Fatty fish such as salmon, tuna and mackerel and sardines.
• Rainbow trout.
• Beef (cow) liver.
• Mushrooms.
• Egg yolks.
• Cod liver oil.

You can also get vitamin D from fortified foods. Be sure to check the nutrition labels to find out if a food has vitamin D. Foods that often have added vitamin D include:

• Cow’s milk and soy, almond and oat milk.
• Breakfast cereals.
• Orange juice.
• Other dairy products, such as yogurt.

Vitamin D is in many multivitamins. There are also vitamin D supplements.

Talk to your healthcare provider if you’re concerned about getting enough vitamin D.

Outlook / Prognosis

What are the possible complications of vitamin D deficiency?

The most serious complications of vitamin D deficiency include:

• Low blood calcium levels (hypocalcemia).
• Low blood phosphate levels (hypophosphatemia).
• Rickets (softening of bones during childhood).
• Osteomalacia (softening of bones in adults).

All of these conditions are treatable. While rickets is a treatable and often curable disease, treating it as soon as possible is important. When not treated, milder cases of rickets can result in long-term bone damage that can keep bones from growing properly. Severe cases that aren’t treated can lead to seizures, heart damage and death.

The good news is that thanks to vitamin D-fortified infant formula and fortified cow’s milk, rickets is very uncommon in the United States.

Living With

When should I see my healthcare provider about vitamin D deficiency?

If you’re concerned about whether you’re getting enough vitamin D or if your body is using it properly, talk to your provider.

If you have risk factors for vitamin D deficiency, your provider may recommend checking your vitamin D levels regularly to ensure they’re in a healthy range.

Additional Common Questions

Can you ever have too much vitamin D?

Yes. You can get too much vitamin D if you take too many supplements. Interestingly, you can’t get too much vitamin D from the sun. Vitamin D toxicity is rare, but it can lead to hypercalcemia. Symptoms can include:

• Nausea.
• Increased thirst and urination.
• Poor appetite.
• Constipation.
• Weakness.
• Confusion.
• Ataxia (impaired balance or coordination).
• Dysarthria (unclear speech).

Don’t take higher-than-recommended doses of vitamin D without first discussing it with your healthcare provider. Also, be cautious about getting large doses of vitamin A along with the D in some fish oils. Vitamin A can also reach toxic levels and can cause serious problems.

A note from Cleveland Clinic

Vitamin D is an important vitamin your body needs to be healthy. If you have risk factors for developing vitamin D deficiency or are experiencing symptoms, be sure to contact your healthcare provider to get a blood test to check your levels.