Is there such a thing as too much of a good thing? Anyone who has stared down an entire chocolate cake can attest that yes, there is.
Despite levels of 5,000 IU and even 10,000 IU of vitamin D being readily available with the click of a button, The Institute of Medicine recommends no adult should exceed 4,000 IU a day or else they put themselves at risk of serious health complications.
“Many people are taking too much vitamin D.” Dr. Joann Manson of The Brigham and Woman’s Hospital is working on a study of 25,000 participants to check their vitamin D blood levels. 
The American Academy of Dermatology agrees. Dr. Weinstock of Brown University commented at the annual meeting that “there is an increased risk of falls and fractures associated with vitamin D megadosing.”
So what is considered too high or too low?
“You shouldn’t by pass the satiety level. Your stomach is only so big for a reason.” Dr. Paul Offit, an infectious disease specialist. In his book “Do You Believe in Magic” he discusses the harms of megadosing.
Dr. Offit offers a good rule of thumb: there are 1,000 milligrams of vitamin C in one tablet. That’s the equivalent of 8 cantaloupes. Would you eat 8 cantaloupes a day? If you answered no, then you shouldn’t take that high a dose. “It goes against what nature intends.”
At the end of the day we all want to be the healthiest we can possibly be. Supplements and vitamins can be a great tool to get there, we just need to be mindful of how much is too much. Consider the recommendations, understand how much is too much to self-prescribe, and consult your doctor if you think you need more. Read more about higher doses of vitamin D here http://blog.vitaminddrops.com/can-you-get-too-much-vitamin-d/#_ednref3
To discover megadosing of other vitamins, you can use The Pill Converter.
 Dietary Reference Intakes for Calcium and Vitamin D. Rep. The Institute of Medicine of the National Academics, Nov. 2010. Web. 8 June 2017. <http://www.nationalacademies.org/hmd/~/media/Files/Report%20Files/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D/Vitamin%20D%20and%20Calcium%202010%20Report%20Brief.pdf>. Revised March 2011
 The Fifth Estate. Perf. Gillian Findlany. CBC News. CBC/Radio Canada, 20 Nov. 2015. Web. 08 June 2017. <http://www.cbc.ca/fifth/episodes/2015-2016/vitamins-and-supplements-magic-pills>.
 Sullivan, Michele G. “Large, Intermittent Vitamin D Doses May Increase Fracture, Fall Risk in Elderly.” Family Practice News. MDedge, 3 Mar. 2017. Web. 08 June 2017. <http://www.mdedge.com/familypracticenews/article/132688/geriatrics/large-intermittent-vitamin-d-doses-may-increase>.