Abstract: Disclosed herein are a dielectric fluid composition and a method thereof. Also disclosed are viscosity modifiers and a method of lowering the viscosity of an oil-based dielectric fluid. The composition includes an oil with a high mono-unsaturated fatty acid content and one or more fatty acid alkyl esters, each having a fatty acid and an alkyl moiety, wherein the alkyl moiety of the fatty acid alkyl esters has 1 to 4 carbon atoms, and wherein both the oil and the fatty acid alkyl ester are in the range of 40%-60% v/v of the dielectric fluid composition. The viscosity modifier includes one or more fatty acid alkyl esters with an alkyl moiety and a fatty acid moiety, wherein the alkyl moiety has 1 to 4 carbon atoms. The method of lowering the viscosity includes blending the viscosity modifier and a vegetable oil-based dielectric fluid in a ratio of 40:60-60:40.