Gilbert N. Lewis (an American physical chemist) was nominated 41 times but never won the Nobel Prize in Chemistry.
https://en.wikipedia.org/wiki/Gilbert_N._Lewis

Positive side:
I know this place is not presumed to post such things but endeavoring 41 times for the prize is almost unbelievable.

Negative side:
On March 23, 1946, Lewis was found dead in his Berkeley laboratory where he had been working with hydrogen cyanide; many postulated that the cause of his death was suicide.