He studied theology, philosophy and alchemy at the University of Giessen obtaining a master's degree in theology in 1693. He published many theological works under the name Christianus Democritus, and most of them are still preserved. He led a very adventurous life, and often got into trouble because of his disputed opinions (and because of money). At one point he was imprisoned for heresy. He created an animal oil known as Dippel's Oil which was supposed to be the equivalent to the alchemists' dream of the "elixir of life."
In 1704 in Berlin, he and the manufacturer Heinrich Diesbach used this oil instead of potassium carbonate in producing red dyes. To their surprise, they obtained a blue dye "Berliner Blau", also called "Preussisch Blau" or "Prussian blue". Together they founded a factory in Paris.
There are claims that during his stay at Castle Frankenstein, he practiced alchemy and anatomy. He was allegedly working with nitroglycerin, which led to the destruction of a tower at the Castle Frankenstein. But this seems to be a modern myth, for it is an anachronism. Nitroglycerin hadn't been discovered in Dippel's time. And although the history of the castle during Dippel's lifetime is well documented, the destruction of a tower - though surely a remarkable event - is nowhere mentioned.
Other rumours about Dippel appear to be modern inventions too. For example, that which said that he performed gruesome experiments with cadavers, attempting to transfer the soul of one cadaver into another. There's also no evidence to the rumour that he was driven out of town, when word of his activities reached the ears of the townspeople.
The local historian, Walter Scheele, believes that the legends told in the villages surrounding the castle were transmitted by Jacob Grimm to Mary Jane Clairmont, translator of Grimm's fairy tales and stepmother of Mary Wollstonecraft Godwin. Scheele also claims that in 1814 Mary, her half-sister Claire Clairmont and Percy Bysshe Shelley are said to have visited Castle Frankenstein, on their way to Lake Geneva. Other historians, whether their field of research is Grimm, Shelley, or the Castle Frankenstein, don't see any evidence for this.
Scheele's claimed letter of Grimm is nowhere to be found. And no evidence can be found that Clairmont was considered as the translator for Grimm's Fairy Tales.