A compound of formula (I) wherein R.sub.1 and R.sub.2 are different and each is chosen from a methyl group and a hydrogen atom; wherein X is chosen from a carboxylic acid group, a carboxylate group, a carboxamide group; or any pharmaceutically acceptable salt, solvate, complex, or pro-drug of said compound. A pharmaceutical composition and a lipid composition comprising a compound of formula (I) is also disclosed. A method for the treatment of obesity, diabetes mellitus, amyloidos-related diseases, cardiovascular-diseases, and cerebrovascular diseases is also disclosed. ##STR00001##