D-IX was a methamphetamine-based experimental performance enhancer developed by the Nazis in 1944 for military application. The researcher who rediscovered this project, Wolf Kemper, said that "the aim was to use D-IX to redefine the limits of human endurance."
German doctors were enthusiastic about the results, and planned to supply all German troops with the pills, but the war ended before D-IX could be put into mass production, though it did see limited use among a handful of Neger and Biber pilots.
History
Due to increased Allied pressure on the German war effort, Nazi Germany had grown desperate for new soldiers to continue the war effort, and one way to mitigate the massive losses was to increase the combative power of the remaining soldiers in the Wehrmacht. Though simpler drugs such as Pervitin and Isophan helped to keep soldiers properly stimulated, Vice Admiral Hellmuth Heye in March 1944 requested a drug that could also provide the users with superhuman strength and a boosted sense of self-esteem.
Pharmacologist Gerhard Orzechowski and a group of other researchers were commissioned in Kiel to develop this drug, and by later in the year developed a formula which contained in each tablet: 5 mg of oxycodone (brand name Eukodal), 5 mg of cocaine and 3 mg of methamphetamine (then called Pervitin, now available under the brand name Desoxyn).
German researchers found that equipment-laden test subjects (inmates from Sachsenhausen concentration camp) could march in a circle for up to 90 kilometers per day without rest while carrying a 20 kilogram backpack.