A team of scientists is proposing a new explanation for some cases of long Covid, based on their findings that serotonin levels were lower in people with long Covid. They said that the biological pathway that their research outlines could unite many of the major theories of what causes long Covid: lingering remnants of the virus, inflammation, increased blood clotting and dysfunction of the autonomic nervous system.
This was really interesting and would explain a lot of my experiences very well. I might have to start tinkering with tryptophan and seeing what happens.