The molecules of formula (I) are useful in treating diabetes, obesity, hypercholesterolaemia, hyperlipidaemia, cancer, inflammation or other conditions in which modulation of lipis of eicosanoid status or functions may be desirable. Formula (I): Z1—Z1—Z2 wherein a) Z1 represents CO2H or a derivative thereof; b) Z2 represents F, H, —CO2H or a derivative thereof; and c) X represents fluorinated alkylene; or a solvate thereof, for example a perfluorinated fatty acid or derivative thereof.