Fumaric Acid Monomethyl Ester-d5 is the isotope labelled analog of Fumaric Acid Monomethyl Ester. Fumaric acid monomethyl ester is one of the most bioactive anti-psoriatic fumaric acid ester metabolite. Fumaric acid monomethyl ester is potent nicotinic acid receptor agonist. Fumaric acid monomethyl ester has also been shown to selectively stimulate of T helper 2 cytokine response. It is also the active metabolite of Dimethyl Fumarate (D464965), a compound that is used as a treatment for the relapsing forms of multiple sclerosis and psoriasis.