Not yet investigated
What we have so far
Oxide is about 4% absorbed and is most of what is sold. Citrate, glycinate and malate are not interchangeable, and the label rarely gives elemental content.
This star is on the map because the show intends to take the question apart properly — the trials, how it is actually tested, whether the thing sold is the thing studied. That work is not done yet, and nothing here should be read as a conclusion. When the investigation is published it will appear on this page.