I remember that this movie revolved around two main characters, male and female, who I think were searching for weird stuff to explain them scientifically. There were several plots they discovered, in one a fat professor finds a potion from a creepy person, that grants wishes. He wishes to be lighter and does not become less fat, but becomes weightless and starts floating around. The main characters fix his problem by sewing, I think, lead into his coat, and the scene ends in him teaching, the sewing breaking and he almost lifts off, but he grabs the blackboard and doesn’t float off anymore. Also he becomes more confident after this.
In another scene, there is a bald guy who with the same potion wishes that his hair grew, and his hair started growing and growing, soon he had a 1 meter long hair, then 2 meters, then he started having his hair cut continuously in a shop, but soon the shop was overgrown with hair. I don’t remember anything else.
I really hope that someone knows this movie.
P.S. I think it was set in the UK (possibly), in a time when they had trains and electricity but not any modern technology. Also they could not find the guy giving the potions, he was always mysterious and kept disappearing after he gave some people the potion, and the potion involved I think some ritual, nothing to scary, just eerie.
I found it: The Infinite Worlds of H.G. Wells (2001)
https://www.imdb.com/title/tt0280770/
Glad you found it and thanks for letting us know!