hi colin: glandulars are an exellent way to rebuild and repair damaged organs, they have been used for thousands of years to treat thyroid,adrenal,pituatary,liver, kidney ect......disorders untill 1968 they were actually being by made by some of the leading pharaceutical companies,then synthetic hormones like hydrocortisone and others started to make there way on market ,they found that there was no money in natural alternative treatments (you can not patent natural remedies) most glandulars are made from either cow or pig organs they are very compatible with the human body unlike synthetics