I started with 300mg every night - 2 tablets from a brand called Swisse. I am now taking just 150mg a day since I think my body is back to normal. They also have powder type and i was also taking that at the beginning and your body absorb it really quick!
citrate was what I had/have (my wife usually buy it for me and I just looked at the label) and you just taught me a list of other options I never knew about! XD