Started berberine years back thinking it'd help with insulin sensitivity. Read some newer research though that questions how much it actually does for fat storage. Might not be worth the cost or effort.
My wife's about to get prescribed one of these. There's a lot of upside to it, looks like the trade-offs are digestive stuff and maybe sex drive. And if you don't keep up with lifestyle changes, the weight might come back?
Water weight could definitely be it. Ive heard similar things about initial stalls. Sounds like youre staying consistent with everything that matters: sleep, intake, training, hydration. Stick with it, the plateau should break.