Tasteless or bad-tasting vitamins that must be swallowed whole are not food and cannot be eaten as food. They therefore do not require a hashgacha. If, however, you know for a fact that they contain non- kosher ingredients, then they should not be ingested by a totally healthy person and can be used only to treat a sickness, or disorder even if these are not life-threatening. Homeopathic elements are all “batel”- they are so minimal as to be considered non-existent. The base that they are in- distilled water? oil?- must be kosher (Shmirat Shabbat K’Hilchata ch.40 n.169; Nishmat Avraham, Orach Chayyim 466; B’Ohala shel Torah I 21).