Vitamin D Dosages: Your GoodRx Guide
Key takeaways:
Vitamin D is available as a prescription as well as an over the counter (OTC) supplement. There are two forms of vitamin D — vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).
Prescription vitamin D contains 50,000 IU (international units) of vitamin D2. The typical dosage for adults with low vitamin D levels is 1 capsule once weekly. Higher or more frequent doses may be recommended if you have certain health conditions.
Most adults with low vitamin D levels should take 2,000 IU of OTC vitamin D daily. Doses over 4,000 IU daily aren’t recommended without a provider’s OK. And too much vitamin D can be toxic, so it’s best to only take it if your provider tells you to.
Prescription vitamin D is available as a lower-cost generic. GoodRx can help you save over 70% off the average retail price at certain pharmacies.
Access savings on related medications
Table of contents
Vitamin D plays a key role in keeping your bones strong and your immune system healthy. It has become a popular supplement in recent times, with good reason. An estimated 41% of people in the U.S. don’t get enough of it.
If your vitamin D levels are low, your healthcare provider may recommend an over-the-counter (OTC) supplement. Or they may decide a prescription form of vitamin D is a better option. But what’s the difference between them? And what’s the right vitamin D dosage?
What’s the difference between prescription and OTC vitamin D?
There are three main differences between prescription and OTC vitamin D:
The amount of vitamin D per dose. There are two main forms of vitamin D — vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Prescription vitamin D (Drisdol) contains 50,000 IU (international units) of vitamin D2. OTC supplements can contain either vitamin D2 or vitamin D3. But they typically only contain between 400 IU to 10,000 IU per dose.
The dosage forms available. Prescription vitamin D only comes as a capsule. OTC vitamin D comes in a wider range of dosage forms. These include capsules, gummies, liquids, and more.
Prescription vitamin D is FDA-approved. Prescription vitamin D is FDA-approved to treat low vitamin D levels caused by certain health conditions. The FDA also makes sure that it’s manufactured with the proper standards in place. But OTC vitamin D supplements aren’t FDA-approved to treat any health condition. And supplement companies aren’t required to complete testing to ensure that the bottle contains what it says it does.
What’s the typical prescription vitamin D dosage for adults and children?
The recommended dosage of prescription vitamin D2 depends on your age and why you’re taking it.
Rickets
Certain inherited health conditions can make it harder for your body to absorb vitamin D. Low vitamin D levels can lead to a condition called rickets. It causes soft, weak bones and can lead to pain and deformities over time.
The recommended prescription vitamin D2 dosage for rickets caused by genetic changes is 12,000 IU to 500,000 IU by mouth daily. Your healthcare provider will adjust your dosage based on the vitamin D levels in your blood. And keep in mind that doses lower than 50,000 IU aren’t available by prescription. So an OTC form of vitamin D would be needed in that case.
Hypoparathyroidism
Hypoparathyroidism is a condition that occurs when your body doesn’t make enough parathyroid hormone. This can lead to low vitamin D levels.
The approved vitamin D dosage for hypoparathyroidism is 50,000 IU to 200,000 IU daily. You’ll likely also take calcium along with vitamin D. And your provider will keep a close eye on your vitamin D, calcium, and phosphorus levels during treatment.
Low vitamin D levels (off-label use)
Your provider may choose prescription vitamin D if your levels are low for reasons other than those listed above. This is an off-label use of the medication.
Recommended dosages are based on how low your vitamin D levels are. Keep in mind these are off-label dosages — they aren’t FDA-approved.
For vitamin D levels below 25 nmol/L, the recommended dosage for adults and children ages 11 and older is 50,000 IU (1 capsule) once weekly. Adults should take it for 8 weeks, and children for 6 to 8 weeks.
For vitamin D levels between 25 nmol/L and 75 nmol/L, the recommended dosage for adults is still 50,000 IU once weekly for 8 weeks. The recommended dosage for children ages 11 and older is 25,000 IU once weekly for 8 weeks. Since this is less than 50,000 IU, and that’s the only available dose of prescription vitamin D, an OTC form is a better option for this age group.
What’s the typical OTC vitamin D dosage?
The typical OTC vitamin D dosage depends on your age and vitamin D level, as shown in the table below. Again, these are general recommendations — they aren’t FDA-approved dosages. So it’s best to talk to your healthcare provider before starting vitamin D. They can recommend a dosage based on your personal medical needs. Adults shouldn’t take more than 4,000 IU of vitamin D per day without a provider’s OK.
| Age | Recommended dosage by vitamin D level |
|---|---|
| Infants <1 month |
|
| Infants 1-5 months |
|
| Infants 6-12 months |
|
| Children 1-10 years old |
|
| Children 11-17 years old |
|
| Adults 18-74 years old |
|
| Adults 75 years and over |
|
Which form of vitamin D should you take?
Both forms of vitamin D are well absorbed by the body. And they’re equally effective at raising blood levels. But vitamin D3 seems to have a greater and longer-lasting effect than vitamin D2.
What happens if you miss a dose of vitamin D?
If you miss a dose of vitamin D2 or vitamin D3, take it as soon as you remember. But if it’s close to time for your next dose, skip the missed dose and take your next dose as scheduled. Don’t take an extra dose to make up for a missed dose.
What should you do if you take too much vitamin D?
One extra dose of vitamin D is unlikely to be an issue. But it can be toxic if you take too much — either over time or as one large dose. It’s best to only take vitamin D if your provider tells you to. And follow their recommended dosage instructions carefully.
Symptoms of too much vitamin D include nausea and vomiting, weakness, and mental changes. It can also lead to kidney damage, irregular heartbeat, and even death in severe cases.
If you or someone you know has taken a large amount of vitamin D, contact Poison Control at 1-800-222-1222. If symptoms seem severe or life-threatening, seek emergency medical care.
How to save on prescription vitamin D
There are ways to save on prescription vitamin D, which is available as a generic medication. GoodRx can help you save over 70% off the average retail price of the generic version. Prescription Vitamin D2’s price at certain pharmacies is as low as $5.02 for a 3-month supply with a free GoodRx discount.
GoodRx can also help you save on OTC vitamin D. If your provider writes a prescription for it, OTC vitamin D’s price at certain pharmacies is as low as $7.76 for a month’s supply.
The bottom line
Vitamin D is available as both a prescription and OTC supplement. It comes in two forms — vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).
Prescription vitamin D contains 50,000 IU of vitamin D2. The typical adult dosage for low vitamin D levels is 1 capsule once weekly. But you may need to take it more often or at a higher dose if you have a genetic health condition that causes low vitamin D levels.
The recommended OTC vitamin D dosage for most adults with low vitamin D levels is 2,000 IU daily. Higher doses may be needed if your vitamin D levels are very low. But dosages over 4,000 IU daily aren’t recommended without a provider’s OK. And it’s best to only take OTC vitamin D if your healthcare provider tells you to. Taking more than you need can be harmful to your health.
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References
Aphena Pharma Solutions - Tennessee, LLC. (2023). Ergocalciferol- ergocalciferol capsule, liquid filled [package insert].
Bleizgys, A. (2021). Vitamin D dosing: Basic principles and a brief algorithm (2021 update). Nutrients.
Dietary Supplement Label Database. (n.d.). Vitamin D. National Institutes of Health, Office of Dietary Supplements.
Ghazi, A. A., et al. (2017). Hereditary vitamin D resistant rickets: Clinical, laboratory, and genetic characteristics of 2 Iranian siblings. International Journal of Endocrinology and Metabolism.
MedlinePlus. (n.d.). Rickets.
MedlinePlus. (2018). Ergocalciferol.
MedlinePlus. (2020). Cholecalciferol (vitamin D3).
MedlinePlus. (2022). Hypoparathyroidism.
National Institutes of Health, Office of Dietary Supplements. (2023). Vitamin D: Fact sheet for health professionals.
