Argentyn 23 Professional Bio-Active Silver Hydrosol contains only 99.999% pure silver and purified water meeting USP NF standards for pharmaceutical-grade purified water. It is a unique mixture of the most active and effective species of silver – positively charged silver ions and particles of an unprecedented size as small as 0.8 nanometers. With the smallest particles and highest bio-activity, it is the ultimate, modern refinement of colloidal silver, offering the most effective* and safe* dietary silver supplement available.