Jumping in here because I’ve been trying to figure out pretty much the same thing! One thing that stood out to me about products like Black Burn Stacker 2 is how often their ingredient lists lean heavily on caffeine, synephrine (from bitter orange), yohimbine, and sometimes green tea extract. These all have research supporting mild thermogenic effects, but usually at higher/isolated doses, and the actual synergy in stacked formulas is rarely thoroughly studied.
I haven’t seen robust clinical trials specific to these combinations—mostly either rodent models or studies on single-ingredient effects. A lot of the efficacy claims seem extrapolated. Also, these stimulant-heavy blends can crank up blood pressure or cause heart palpitations, especially in sensitive users or those mixing with other stimulants. It’s also tricky to recommend safe dosages because proprietary blends often don’t list exact amounts.
So yeah, while there’s a theoretical basis for fat burning, the lack of human data and possible side effects are big caveats. If anyone finds any independent, peer-reviewed studies on these complete formulations, I’d love to read them!