They have relatively low pressures , so low fusion rate. The energy generated is the product of nuclear fusion of hydrogen into helium (gas) by the way of the proton-proton.
7.5% the mass of the star Average red dwarf has 1/10,000th the luminosity of our sun
The minimum mass a red dwarf must have to eventually evolve into a red giant is 0.25 M
many red dwarf stars have gotten taken into black holes.