What Are the Effects of Taking 50,000 IU of Vitamin D Weekly? | Livestrong.com (2023)

What Are the Effects of Taking 50,000 IU of Vitamin D Weekly? | Livestrong.com (1)

Swordfish, salmon and tuna are rich sources of vitamin D.

Image Credit: OksanaKiian/iStock/GettyImages

Forty-two percent of the American population doesn't get enough vitamin D, reports the director of wellness at Mercy Medical Center, Stephanie Wheeler. This nutrient, crucial for bone health, immune function and controlling inflammation in the body, is found in foods and also synthesized by the body from exposure to sunlight. If you're deficient, taking a ​vitamin D supplement​ can help.


Fifty-thousand IU per week is well above official recommendations proposed to avoid health risks. However, it's often prescribed in this dosage to correct vitamin D deficiencies. But should you take this amount if you don't have a deficiency? Recent research shows that it might not be harmful and could actually be helpful for the general population.

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A weekly dosage of 50,000 IU of vitamin D is almost double the tolerable upper intake level. It may or may not pose health risks.

Tolerable Upper Intake Level

The tolerable upper intake level, or UL, is the ​maximum amount of a nutrient that is safe​ for the general population to get each day on a regular basis. Above this amount, the health risks increase; the greater the excess intake, the greater the health risks, according to the National Institutes of Health (NIH).


The National Academy of Medicine (NAM) has set the UL for vitamin D at 4,000 IU, or 100 mcg, per day for all adults. Taking 50,000 IU of vitamin D each week, divided among seven days, would give you 7,143 IU each day, which is nearly double the UL.

How Much You Need

The NAM developed the recommended daily allowance, or RDA, based on the needs of the general population. This is the amount it has determined will prevent deficiencies and the negative health effects caused by getting too little vitamin D in 97.5 percent of people.


The RDA for vitamin D for men and women, ages 19 to 70, is 600 IU daily. If you take 7,143 IU each day, that's nearly 12 times or 1,200 percent of the RDA.

Conflicting Vitamin D Recommendations

Not everyone agrees with the National Academy's proposed RDA and UL. Some reputable sources believe that people need well more than the RDA, and in fact more than the UL. For example, the Vitamin D Council, a California-based nonprofit, recommends adults take 5,000 IU daily or 8.3 times the RDA. People with overweight and obesity may require as much as up to 8,000 IU per day, or more than ​13 times the RDA​.


According to the Endocrine Society, the current official guidelines are based specifically on bone health but do not take into account vitamin D levels needed to prevent other conditions that may result from vitamin D deficiency. Specifically, NAM set the benchmark for deficiency at a blood level of 20 ng/ml of 25-hydroxyvitamin D, the main circulating form of vitamin D in the body. However, the Endocrine Society classifies blood levels below 29 ng/ml as insufficient and recommends a better target is 30 ng/ml or higher.



Director of the General Clinical Research Unit and Bone Health Care Clinic at Boston University Medical Center, Michael F. Holick, M.D., Ph.D., told Endocrine News, a publication of the Endocrine Society, that he believes blood levels between 40 and 60 ng/ml are an even better goal and that blood levels up to 100 ng/ml are perfectly safe.

Scientific Support: Increased Vitamin D

Research shows proponents of increased vitamin D intakes may be onto something. A 2017 study in Dermato-Endocrinology evaluated the effects of daily intakes up to 15,000 IU and blood levels up to 120 ng/ml on calcium regulation, kidney, liver and immune function. Using data collected from 3,882 participants between 2013 and 2015, the researchers found that even at blood levels of 120 ng/ml there was ​no negative effect​ on calcium regulation and no incidence of toxicity.


In a 2016 study in the North American Journal of Medical Sciences, participants took 50,000 to 100,000 IU of vitamin D per week without a significant change in blood calcium levels. Serum vitamin D levels also rarely exceeded 100 ng/ml, and there were no signs of toxicity.

A Simple Miscalculation?

According to a statistical analysis published in Nutrients in 2014, the NAM actually miscalculated its estimation of the RDA for vitamin D. In reviewing the 10 studies used by the NAM to determine the RDA, the researchers discovered that although the NAM calculated that 600 IU is the amount needed to reach serum 25-hydroxyvitamin D (25(OH)D) levels of 20 ng/ml, those calculations were ​critically underestimated​.


In fact, the studies showed that 8,895 IU might be required to meet the target blood level of 20 ng/ml. The authors conclude that the NAM's miscalculation poses serious risks for bone health and disease and injury prevention in the general population.

Vitamin D Side Effects

There are health risks for taking too much vitamin D, but perhaps not at the levels previously suspected. Taking a 50,000 IU ​vitamin D supplement​ weekly is not likely to get you to that level. But it's a good idea to know what these possible dangers are and at what intake and blood level the mainstream medical community says you are at risk.



Read more:Symptoms of a Vitamin D Deficiency in Adults

Vitamin D Toxicity

Vitamin D is a fat-soluble vitamin, meaning any excess is stored in your fat cells. This differs from water-soluble vitamins, like the B vitamins, which get carried out in urine and need to be replaced each day. Excess fat-soluble vitamin intake can lead to a buildup of the nutrient in your body, which, over time, can be toxic, according to the NIH. Excess ​vitamin D side effects​ include:

  • Anorexia
  • Weight loss
  • Frequent urination
  • Heart arrhythmia

More seriously, excess intake can increase blood levels of calcium, which can cause vascular and tissue calcification. This can damage the heart, blood vessels and kidneys.

Long-term intakes of 10,000 to 40,000 IU daily and consistent blood levels of 200 ng/ml or greater are considered to be potentially toxic. According to the NIH, intakes below 10,000 IU daily aren't likely to cause toxicity symptoms.

Other Potential Negative Effects

But toxicity may not be the only thing to worry about. Even at lower intakes, as low as 30 to 48 ng/ml, the NIH reports potential risks including increased all-cause mortality, greater risk of some cancers, such as of the pancreas, increased risk of cardiovascular events, and a higher incidence of falls and fractures among older adults.

What Should You Do?

These conflicting recommendations and data pose a dilemma for the consumer. A daily intake of 7,000 IU is highly unlikely to cause vitamin D toxicity and very unlikely to cause other problems. However, there's no way to be sure.


If you think you may be deficient in vitamin D, see your doctor for a ​blood test​. Get her expert advice on the right blood level. If testing shows you are below this level, then follow your doctor's recommendation for how much vitamin D to take each day.

Food, Sunlight and Supplements

There's no risk of toxicity from vitamin D in foods or excess exposure to sunlight. It is only caused by taking excessive amounts of ​vitamin D pills​ over a period of time. If you don't have a deficiency requiring medical treatment, you may be able to hedge your bets by getting more D from natural sources.

Safe Sun Exposure

When you spend time outdoors, ultraviolet B radiation (UVB) penetrates the skin, which converts it to a substance called cutaneous 7-dehydrocholesterol, then to previtamin D3 and finally to vitamin D3. Many factors affect how easily your body creates the vitamin: the season, the time of day, the length of the days where you live, the amount of melanin your skin produces, smog and cloud cover and sunscreen among them. Therefore it's not a good idea to rely on getting everything you need from sun exposure.

Furthermore, organizations like the Skin Cancer Foundation and the American Academy of Dermatology caution that there is no such thing as safe sun exposure. According to Anne Marie McNeill, MD, PhD, and Erin Wesner, not using sunscreen increases your risk of squamous cell carcinoma, melanoma and premature skin aging.

It doesn't take a lot of sun exposure for your skin to make vitamin D. About 10 to 15 minutes on the legs, arms, abdomen and back is more than enough. However, McNeill says even that amount of sun exposure can cause dangerous DNA damage, and she recommends protecting your skin with SPF 15 or higher whenever you venture outdoors.

Vitamin D in Your Diet

A better way to get your D is through a healthy diet. According to the NIH, very few foods naturally contain vitamin D; however, there are a few very rich sources, including:


  • Swordfish: 566 IU per 3 ounces
  • Sockeye salmon: 447 IU per 3 ounces
  • Tuna in canned water: 154 IU per 3 ounces
  • Beef liver: 42 IU per 3 ounces
  • One large whole egg: 41 IU
  • Sardines canned in oil: 46 IU in two sardines

Other commercially prepared foods are often fortified with vitamin D. Some examples include:

  • Orange juice: 137 IU per cup
  • Milk: 115 to 124 IU per cup
  • Yogurt: 80 IU per 6 ounces

Regularly including these foods in your diet can often help you get all the vitamin D you need without sun exposure or a supplement.

Vitamin D Deficiency

Not getting adequate vitamin D can also have serious consequences. In its role as a hormone, vitamin D aids the regulation of more than 200 genes in the body. Some of the jobs vitamin D is responsible for include preventing the multiplication of abnormal cells in breast and colon tissue and helping to regulate blood pressure in the kidney and blood sugar in the pancreas.

Additionally, Erin Michos, M.D., M.H.S., reports that there is a strong connection between vitamin D deficiency and an increase in risk of heart attack, congestive heart failure, peripheral arterial disease (PAD), stroke, high blood pressure and diabetes.

Read more:9 Ways to Help Avoid Vitamin D Deficiency

High-Risk Populations

For certain people, getting more than the established RDA may be especially important, according to MedlinePlus. These include older adults whose kidneys aren't as good at converting vitamin D to its active form, people with darker skin colors, people with digestive disorders such as Crohn's or celiac disease, people with obesity, those with chronic kidney or liver disease and people with lymphomas. These people should be sure to have ​their blood levels tested​ regularly and to adhere to their doctor's recommendations for diet and supplementation.




What are the side effects of 50 000 IU vitamin D once a week? ›

Too much vitamin D can cause harmful high calcium levels. Tell your doctor right away if any of these signs of high vitamin D/calcium levels occur: nausea/vomiting, constipation, loss of appetite, increased thirst, increased urination, mental/mood changes, unusual tiredness.

What are the side effects of taking 50000 units 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.

Is it OK to take 50000 IU of vitamin Da Week? ›

Healthcare professionals may recommend people who are very low in vitamin D take very high weekly doses of 50,000 IU for 8 weeks, followed by a maintenance dose of 2,000 IU per day after their levels reach 30 ng/mL ( 3 ).

Why would a doctor prescribe 50000 units of vitamin D? ›

If the amount in your blood is below 20 ng/mL, your levels are inadequate; if it's below 12 ng/mL, that means you're deficient in the nutrient. If that's the case, your doctor may prescribe a megadose of 50,000 IUs to take once a week for six to 12 weeks to raise the level of vitamin D circulating in your body.

Does vitamin D give you energy? ›

Vitamin D is vital for making our muscles work efficiently and boosting energy levels, new research from Newcastle University has shown.

Is 50000 IU of vitamin D per week too much? ›

For the majority of the population, a daily intake of 400-800IU of vitamin D is adequate. Even on the high end, this would only equal about 5,000IU weekly. However, some research has shown that some patients who are vitamin D deficient may need up to 50,000IU weekly to reach normal ranges.

Can too much vitamin D make you tired? ›

Excess Vitamin D

You may also develop kidney stones or kidney damage. Other symptoms of vitamin D toxicity include weakness, fatigue or tiredness, vomiting, weight loss, itchy skin, constipation and muscle control issues.

Can vitamin D make you tired? ›

Most people with vitamin D deficiency are asymptomatic. However, if you're exhausted, your bones hurt, you have muscle weakness or mood changes, that's an indication that something may be abnormal with your body. Symptoms of vitamin D deficiency may include: Fatigue.

Why do doctors prescribe high doses of vitamin D? ›

Doctors may prescribe higher doses to treat medical conditions such as vitamin D deficiency, diabetes, and cardiovascular disease, for a short period of time. Daily use of high-dose vitamin D supplements for several months is toxic.

How long does vitamin D 50000 stay in your system? ›

Because the metabolism of vitamin D is complex and excess amounts can be stored in fat and other tissues, it is difficult to determine how long a daily dose of vitamin D would stay in the body, but it appears that large doses will last for approximately two months.

What are the symptoms of vitamin D withdrawal? ›

Vitamin D deficiency symptoms

Symptoms arising from vitamin D deficiency include fatigue, depressed mood and bone and muscle pain.

How long does it take for vitamin D to kick in? ›

How Long Does It Take for Vitamin D to Work? If you have a vitamin D deficiency, you may notice improvements within 4-6 weeks of consistent supplementation. However, that timeframe can vary depending on what your baseline vitamin D levels are.

Is 50000 IU vitamin D3 too much? ›

In summary, long-term supplementation with vitamin D3 in doses ranging from 5000 to 50,000 IUs/day appears to be safe.

Is blood pressure a side effect of vitamin D3? ›

Conclusion: Oral vitamin D3 has no significant effect on blood pressure in people with vitamin D deficiency. It reduces systolic blood pressure in people with vitamin D deficiency that was older than 50 years old or obese.

Is anxiety a side effect of vitamin D3? ›

Several studies have shown a direct relationship between the excessive dosage of vitamin D supplements and anxiety. In addition, individuals suffering from psychological illnesses have experienced problematic behaviour to hide the pain symptoms.

What does vitamin D fatigue feel like? ›

Symptoms when vitamin D is low

Fatigue. Not sleeping well. Bone pain or achiness. Depression or feelings of sadness.

Does vitamin D affect sleep? ›

Growing evidence has demonstrated that vitamin D has a role in sleep regulation [12]. Specifically, vitamin D deficiency (VDD) can increase risk of sleep disorders and is associated with sleep difficulties, shorter sleep duration, and nocturnal awakenings in children and adults [13,14,15].

Why does vitamin D make you feel good? ›

The positive effects that vitamin D has on our mental and physical wellbeing are huge. These benefits range from helping fight depression by increasing serotonin, the hormone key to stabilising mood and increasing happiness and also helping improve your sleep.

When should I take vitamin D morning or night? ›

While the best timing has not been established, scientific data to confirm anecdotal reports that supplementing at night may interfere with sleep is unavailable. Current research suggests you can fit vitamin D into your routine whenever you prefer.

What is the difference between vitamin D and vitamin D3? ›

There are quite a few differences between vitamin D and vitamin D3, but the main difference between them is that vitamin D is a fat-soluble vitamin that regulates calcium and phosphorous levels in the body, whereas the vitamin D3 is the natural form of vitamin D produced by the body from sunlight.

How long does it take to recover from vitamin D deficiency? ›

How Much Vitamin D Do I Need Per Day? Besides going outdoors in the sunshine, there are two others ways to improve the amount of vitamin D in your system: eating foods rich in vitamin D and supplements. “Adding an over-the-counter vitamin D supplement can make improvements in just three to four months time.

Can too much vitamin D cause leg pain? ›

How too much can hurt: Vitamin D blood levels exceeding 100 ng/mL can be dangerous. The extra vitamin D triggers extra calcium absorption. This can cause muscle pain, mood disorders, abdominal pain and kidney stones. It may also increase risk for heart attack and stroke.

When I take vitamin D my joints hurt? ›

What's more, taking too much vitamin D can also negatively impact our health as well as our joint pain because our body simply can't cope! If toxic levels of vitamin D build up in the body it can interfere with your body's absorption of calcium.

Can low vitamin D cause leg pain? ›

Humans with vitamin D deficiency exhibit muscle pain in muscles at multiple locations. However, the strongest association between vitamin D deficiency and pain is reported to occur in leg muscles (Heidari et al., 2010).

Why do I feel worse after taking vitamin D? ›

And some will find that taking vitamin D supplements makes them feel worse; probably because the high PTH turns the supplements into high concentrations of 1, 25 dihydroxy vitamin D which is the active form, causing symptoms of vitamin D toxicity. When taking vitamin D makes you feel worse, you should immediately stop.

Which fruit is rich in vitamin D? ›

Oranges are one of the fruits rich in Vitamin D as its juice is fortified with calcium & vitamin D. This is one of the best sources of vitamin D for people who are lactose intolerant and cannot include milk & dairy products in their diet.

What level is considered severe vitamin D deficiency? ›

Today, 25(OH)D less than 12 ng/mL is considered evidence of severe vitamin D deficiency.

What is the highest amount of vitamin D you can take daily? ›

Unless your doctor recommends it, avoid taking more than 4,000 IU per day, which is considered the safe upper limit.

What is the best way to absorb vitamin D? ›

Because Vitamin D is a fat-soluble vitamin, it's best absorbed in the bloodstream in the presence of dietary fat. It also helps to eat Vitamin D-rich food from animals and take supplements that contain Vitamin D3.

Can I take 50000 IU of vitamin D3 once a week? ›

In patients with vitamin D levels less than 20 ng/mL, start with 50,000 IUs of vitamin D3 once a week for 6 to 8 weeks. After that, a dose of 800 to 2000 IU per day should be taken to maintain vitamin D levels above 30 ng/mL.

What are the most common side effects of vitamin D3? ›

What are the side effects of Vitamin D3 (Cholecalciferol (Vitamin D3))?
  • chest pain, feeling short of breath;
  • growth problems (in a child taking cholecalciferol); or.
  • early signs of vitamin D overdose--weakness, metallic taste in your mouth, weight loss, muscle or bone pain, constipation, nausea, and vomiting.
Mar 29, 2022

Can vitamin D supplements cause side effects? ›

Safety and side effects

However, taking too much vitamin D in the form of supplements can be harmful. Children age 9 years and older, adults, and pregnant and breastfeeding women who take more than 4,000 IU a day of vitamin D might experience: Nausea and vomiting. Poor appetite and weight loss.

Is 50000 IU of D3 too much? ›

In summary, long-term supplementation with vitamin D3 in doses ranging from 5000 to 50,000 IUs/day appears to be safe.

What organs does vitamin D3 affect? ›

Vitamin D undergoes further chemical changes, first in the liver and then in the kidneys, to become calcitriol. Calcitriol acts on the intestine, kidneys, and bones to maintain normal levels of blood calcium and phosphorus.

What happens to your body when you start taking vitamin D3? ›

Recent studies suggest that vitamin D3 may help lower blood pressure in people with hypertension and vitamin D deficiency as well as certain groups of people with hypertension only.

Does vitamin D3 affect blood pressure? ›

It reduces systolic blood pressure in people with vitamin D deficiency that was older than 50 years old or obese. It reduces systolic blood pressure and diastolic pressure in people with both vitamin D deficiency and hypertension.

What are the signs you need vitamin D? ›

Symptoms when vitamin D is low
  • Fatigue.
  • Not sleeping well.
  • Bone pain or achiness.
  • Depression or feelings of sadness.
  • Hair loss.
  • Muscle weakness.
  • Loss of appetite.
  • Getting sick more easily.

Why does vitamin D make me sleepy? ›

You'll be sleepy the next day. Several studies even saw a dose-dependent relationship between vitamin D levels and sleep. [1,2] This adds to the evidence that there is a direct, linear relationship between vitamin D and sleep measures. This also means that improving your vitamin D by any amount will improve your sleep.

What happens to your body when you take vitamin D everyday? ›

It Can Help Prevent Bone Diseases Such as Osteoporosis

That's why getting enough vitamin D is critical for warding off bone diseases, such as rickets in children, osteomalacia in adults, and osteoporosis in older adults, says the NIH. Rickets is marked by soft and weak bones in children.

What health problems can vitamin D cause? ›

Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart. If you choose to take vitamin D supplements, 10 micrograms a day will be enough for most people.

What is the difference between D and D3 vitamin? ›

There are quite a few differences between vitamin D and vitamin D3, but the main difference between them is that vitamin D is a fat-soluble vitamin that regulates calcium and phosphorous levels in the body, whereas the vitamin D3 is the natural form of vitamin D produced by the body from sunlight.


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