50,000 IU a day of vitamin D is a huge dosage. I would never consider taking more than 10,000 IU a day unless my blood vitamin D levels were monitored very closely. Even then, I would not want to be on such a high dosage for so long.

Even if I did have my blood vitamin D levels checked, and they did turn out very low, I still wouldn't feel comfortable taking more than 20,000 Iu a day. Without blood testing, I will not take more than 10,000 IU a day.