Trace minerals are usually "metalic minerals"--inorganic and difficult for the body to convert into usable materials. The ultimate mineral supplement is seawater itself, from depths where the minerals are organic (isotonic) and completely compatible with human tissues, particularly when diluted to 1/3 which makes it identical to human blood plasma, or to any mammal blood plasma for that matter. Look at the research on http://www.oceanplasma.org It contains every mineral known to man and other living components Science hasn't even figured out yet.