Hi Becca. My dr found out through routine bloodwork that my Vitamin D level was very low. About a 9 when it should be about a 30-50. Not sure of the exact numbers right now. My memory is not too good these days. I started taking vitamin d with calicium (for my osteopnia (bone thinning) in my hips and after about a year my vit d level is now up to about a 48! My dr told me that I had to get my vit d leve up before my calcium supplements would take full effect in trying to prevent any more bone thinning. I get bloodwork done every year too because of my rsd and other health issues. Thanks for the great post and reminder to me that I am due for bloodwork and need to call my dr soon. Take care.