I had blood work 6 months go and my results said I had very low vitamin d. I started 1 a day and I could not tell a difference. I one day got the idea to take 5 for a day and I noticed a huge improvement with various joint pain. I don’t have pain while squatting, my hands stop hurting in the cold, I am able to be on my feet for hours at a time with no pain, and my various hip pain disappeared without a trace. I was very concerned about overdosing everyday. One pill is vitamin d3 1000iu.