so is coffee a buzz killer or a buzz enhancer? they don't seem to say

Wake and bake. Involves coffee. All studies are suspect unless they say tgey work well together.

Surely it's going to depend on the individual, as, never mind the effects of different weed strains, everyone reacts differently to coffee and can react differently to different kinds of coffee.

An example is how what I class as "bad" coffee, especially espresso blends with Robusta in them can have my heart going like the clappers but a "good" coffee, like a fresh ground Yrgajeffe, releases so much happy chemicals in my brain the temporary increase in heart rate and blood pressure is immediately countered by the happy chemicals and my heart rate and BP will either stay the same or actually go down and I completely relax.

What you can have, and this goes for any drug and not just weed, is that the temporary stimulant effect CAN make you absorb the cannabinoids faster and therefore hit your brain harder and faster and that can "enhance" the hit but the timing of when you take each hit is absolutely critical, a few seconds on either side and that "mix" isn't there which is why I suspect people do not get any enhancement whatsoever.

I can do without mj in the AM, but it's difficult for me to go without coffee. But, like many others, I do enjoy the two together often. I think the stimulation from the caffeine kind of works nicely with manageable sativa high.

Hippy Speed Ball!!

And they make caffeine vape pens (double barrel it)...

I get extra fried mixing coffee and weed. I don't know about anyone else, but it sure kicks it up a notch for me.