According to researchers from Israel and Canada, people can receive vitamin D supplementation in mega monthly doses just as effectively as daily supplementation. Receiving a dose of vitamin D once every four weeks can ensure that you have enough of the vitamin circulating in your system, and monthly dosing can make it easier of people to stick with vitamin D supplementation.
There was some concern that large doses of vitamin D might cause the system to drastically increase calcium levels in the blood, a potentially dangerous situation, but the research shows this worry to be unfounded. As the study progressed no significant differences in calcium levels were found between daily, weekly, and monthly test groups. The only instance of a test subject having inflated calcium levels was actually someone assigned to the daily supplementation group.
The final findings concluded that vitamin D supplementation can be achieved with equal effectiveness for those receiving it daily, weekly, or monthly. With this laid out, it is apparent that the choice for how often individuals receive their doses should be based on whichever dose is easiest for them to keep up with long-term supplementation. If you are keen on your daily vitamins, once a day works as well as it always has, but now there is an option for those of us who may be less regimented. You can check out further info from the study itself, printed in the September 2008 issue of The Journal of Clinical Endocrinology and Metabolism, below:
JCEM: Author Manuscript