Was your experimentation more casual or rigorous? People take supplements but rarely take the time to even casually log perceived effects or use a self-blinded A/B study (my own lazy ass included). If you took a more rigorous approach I'm curious about your methods.
FWIW, I've played around with a lot of supplements. Generally the effects are non-existent or subtle. I'm not generally given to a placebo effect wrt this kind of stuff
Well, you could make both types in identical cups, put labels on the bottom of the cups, shuffle the cups, drink one, record your observations and take the label from the cup you drank and stick it to your notes.
Assuming it's not detectable via taste I would find a way to pre-make and randomize test/control doses of the additive, and add the assigned vial for that day to my morning coffee.
Biggest issue I think would be making sure that there aren't any tells like flavor or some quality of the additive.
Brew identical looking bottles of cold brew. Label the bottoms 1 through whatever. Mix them up. Label the lids A through whatever. Probably need to add some creamer to mask any possible sediment. Drink from them throughout the week. Note the lid label and your reaction. At the end of the test period look at the bottoms of the bottles to correlate the controls and placebos with your experiences.
I personally don't feel the need with this particular thing though. It's a fairly pronounced difference.
It's also not really susceptible to the placebo effect IMO. Could I imagine some vague promised positive effect? Absolutely yes. Could I imagine the erasure of jitters? I don't think I could placebo that away.
Anyway as linked in another post this is well-studied.
