In addition to his many accomplishments and discoveries in science, Windaus was also one of the very few German chemists who did not work with the Nazis and openly opposed their regime[citation needed].

As the head of the chemical institute at the University of Göttingen, Windaus personally defended one of his Jewish graduate students from dismissal.

Windaus believed that while every man had a moral code, his science was motivated by curiosity, and was not driven by politics, ethics, and applications of his discoveries.

Sterols are nitrogen-free secondary alcohols with high molecular weight that contain alicylic systems, or hydrocarbon rings.

This research of the composition of sterols, along with their connection to vitamins, earned Windaus the Nobel Prize in Chemistry in 1928.

It was also postulated that increase sunlight was improving conditions, but was improperly concluded that cholesterol was the precursor activated via UV light.

[5] In testing this, investigators under Windaus’ instruction found that completely pure cholesterol - converted into its dibromide and recrystallized - had lost its antirachitic effects upon irradiation.

The three UV absorption peaks (see image) of the active impurity was used to purify, and become highly concentrated through high-vacuum distillation and charcoal adsorption techniques.

This production of Vitamin D2, or calciferol (see image), was a complete cure to rachitis – 100,000 times more effective than fish liver oil – and Windaus and his group were able to determine its chemical properties.