They do lower blood pressure and heart rate. This is a good thing when used with DMT because DMT slightly increases blood pressure and heart rate, so they tend to cancel each other out.
The danger from using harmala alkaloids has been dramatically exaggerated because they were once believed to be full non-reversible MAOI compounds. But they actually aren’t. They are RIMAs. RIMAs are many times safer that full non-reversible MAOI compounds.
Some people use ayahuasca on a daily basis and they seem to be fine.
Yopo is often taken while chewing caapi. In some locations they do this everyday.
Tobacco also has harmala alkaloids in it and some people smoke it all day long, everyday for years. They end up getting cancer, but that's not from the harmala alkaloids.
No one has ever died from taking peganum harmala or caapi. Both have been used for hundreds of years. That should attest to their relative safety in human beings.
You’ll often seen harmine and harmaline lumped together in text as if they are one and the same. A rue extract contains a mix of harmine and harmaline. The two are actually very different in effects. Most of the sedative “drugged” or “stoned” feeling comes from harmaline and not harmine. Harmine is more like a real psychedelic and harmaline is more of a sedative. As far as toxicity goes, harmine is about 1/2 as toxic as harmaline. Harmaline really feels like a heavy drug compared to harmine. Harmine is a much cleaner, clearer experience.
Even with the lack of negative reports on the daily use of harmala alkaloids by the natives, I would steer away from using anything like that on a daily basis until some real scientific studies are done on the subject using human beings. Animal tests aren’t that useful. For example, a chocolate candy bar can kill a dog, but a person can eat chocolate all day and be fine.