Generally ….3-1200mg/d as needed and dosed around meals.
IMO, ALA is under-rated with a lot of guys here. I've been using it for like 20 years. Find a good supplier though, as a lot of ALA is crap. If in doubt, TN has a good 300mg racemic ALA, though I prefer r-ALA.
There are a lot out there....Berberine, ALA, Cinnamon, Chromium, Vanadyl Sulfate (Still sold?), and a few others.