A dose of 50,000 IUs of vitamin D once a week is a common prescription to boost your vitamin D level if it is low. Pay attention to how often your doctor wants you to take this. It is not once a day – that would be too much.
Typically your doctor will have you take this dose once a week for 2 to 3 months and then recheck your vitamin D blood level.
Some doctors recommend that you continue the dose of 50,000 IUs every other week for long term maintenance rather than prescribing a daily dose.
Note that the prescription strength of 50,000 IUs is vitamin D2. Some online sources that do not require a prescription may supply vitamin D3. A dose of 50,000 IUs of vitamin D2 should be taken at intervals no greater than three weeks because the blood levels wane. One dose of vitamin D3 lasts longer but you should take 50,000 IUs of vitamin D no greater than one month apart.