A lack of vitamin D can impact several areas, including your back and muscles. This can lead to bone deformities such as rickets in children, and several conditions in adults. If you are spending a lot of time indoors, the NHS suggests you should take 10 micrograms of vitamin D a day to keep your bones and muscles healthy. Over-supplementation of vitamin D, however, can be harmful and should be avoided.
The National Institutes of Health (NIH) says getting too much vitamin D can be “harmful”.