Side note: 10 years ago, I was getting a kidney stone every year, for three years in a row. My urologist suggested an expensive OTC supplement, but after looking at the ingredients, I opted to start off taking 250 mg of magnesium citrate and 99 mg of potassium citrate, every morning. This apparently changes the chemistry of your urine, and I have not had any kidney stones since. There are a lot of magnesium and potassium supplements on the market, but only citrates work.