Anyone ever used these before?
Not worth it. From the research, you can get far more absorbtion from just upping the dose of the vitamin than paying extra for colloidal suspension
There is a cassette tape floating around by some Dr. who is a big believer in (and seller of) collodial minerals. I dont know if you need them or not, but he is a hell of a speaker and the tape pretty convincing. I think a web search of collodial minerals would find him pretty quickly. He used to a vet and then became an MD and won a Nobel or something as I recall.