I have done a lot of research. Be careful to not TAKE THE ENTIRE CAPSULE! It's too large of a dosage to take every day. Maybe the first time you take it, sure. But that's it (even if you are deficient in this amazing mineral!)
Rumor has it that the amino acid l-valine (one of the three BCAAs) oxidizes (makes available, releases) manganese. So if you are experiencing symptoms of manganese deficiency, you may not be deficient at all . . . it's just not being used up. So maybe look into BCAAs before MEGADOSING with manganese!
But I can honestly say this brand's quality is GREAT. This is probably the mineral who is the "manager" for bone growth (and maintenance). But manganese is also a neurotoxin. So please DO TAKE WITH CARE. Unlike macro minerals like calcium and magnesium, taking high doses (which means this entire capsule) of a TRACE mineral is VERY dangerous, especially long-term.
But the good thing is that this bottle will last you A LONG TIME . . . and hopefully you don't have to finish the bottle before you have restored required manganese levels for health.