D-γ-Tocotrienol-D6 is an isotope-labeled analog of γ-Tocotrienol (T526175), which exhibits antioxidant properties and belongs to the vitamin E family. It is naturally found in wheat germ oil and bran. In addition, α-tocopherol and γ-tocotrienol derivatives are potential lead compounds for developinganticancer andantiproliferative agents againstMCF-7 and MDVIP(LA)MB-231 breast cancer cells and the A549 lung cancer cells.