In 1958, R W Liebenberg the inventor of Moducare witnessed the dramatic recovery of an old man from a possibly fatal form of BPH after he was treated with a South African herbal extract. That event finally convinced him that certain plants contained a very important active principle, which had not been discovered by man. It also prompted him to embark on research which was to continue for the next forty years.

In 1968, after ten years of private research when R W Liebenberg treated family and friends, in this time he discovered that the active part of the african folk medicinal herb was a fatty substance now known as sterols. Essential Sterolin Products (ESP) was founded to continue research on a formal basis. Prof. Karl Pegel of the University of Natal in Durban and his assistant Engela de Witt were the first scientists sponsored to work for ESP. Their goal was to isolate the elusive, active compound in the plant that was responsible for the remarkable cure I had witnessed ten years previously.

Prof. Pegel and his team were able to extract a fatty substance which was identified as sitosterol by the South African Council for Scientific and Industrial Research (CSIR). Sitosterol had been identified as early as 1922 and was used in large doses to block the absorption of dietary cholesterol. As well they as the sterol they also discovered the sterolin . 

The research team proceeded to develop a product that contained sterols and sterolins in the same ratio as found in the original herbal extract. Their work led to the release in 1974 of  a patented remedy for benign prostatic hypertrophy (BPH). ESP started exporting this product to Germany where it has been prescribed to hundreds of thousands of BPH patients over the past 25 years.