Hygain® Regain® is rapid electrolyte replacer formulated for horses to replace body salts lost during exercise, hot climatic conditions and as an aid in the treatment of dehydration, hypochloraemia and alkalosis. Contains 215g/kg sodium, 468.5g/kg chloride, 152g/kg potassium and 17.25g/kg magnesium. Sodium and Chloride: Common salt (NaCl), which is composed of two ions, sodium (Na+) and chloride (Cl-). They are the major electrolytes of the body.