DEAR HELOISE: People spend money on vitamins without knowing when and how to take them. ● Vitamin C will have the best effect if taken little by little all day long. ● Calcium tablets work best with vitamin D, but be very careful because excessive amounts of vitamin D can be harmful. My grandmother recommended putting lemon juice on my freckles, then sitting in the sun to fade them. Lemon juice will increase your skin's sensitivity to sunlight.