(-)-Menthol-d4 is the deuterium labeled (-)-Menthol (HY-75161). (-)-Menthol is a key component of peppermint oil that binds and activates transient receptor potential melastatin 8 (TRPM8), a Ca2+-permeable nonselective cation channel, to increase [Ca2+]i[1]. Antitumor activity[1].