Been taking these as part of my daily routine for several years. They are good quality at a reasonable price. As a 75 yr old active female, it's very important to include these minerals daily in addition to a balanced diet. My experience has proven that these help me avoid muscle cramps, especially after babysitting for my 2 young active grandsons, and after weekly mowing, edging, trimming of my landscape in central Florida. Very satisfied with this product.