Iboga RB (rootbark) - is the raw bark of the Tabernanthe iboga in a powder form (finely ground). It is incredibly useful for micro-dosing, small-medium flood doses, but it will be harsh on the body if used for a full flood dose for detoxification purposes. The people in Gabon use the rootbark (in some tribes it is not even ground, it is just chewing on raw wood) for medicine and initiation ceremonies.
Iboga TA (Total Alkaloid) - a total alkaloid extract of Iboga. Contains all the alkaloids in the root bark, but in a concentrated form that allows for easier dosing. The TA has a much more natural way of extraction and it provides deeper, boarder and more complex therapeutic qualities. The molecule of the bark is so complex, that tracking down all the effects/purposes and receptors it attaches to is next to impossible.
Ibogaine HCL (ibogaine hydrochloride) - unlike TA, which is a full spectrum alkaloid extract, HCL is an isolated extract, that contains only few of the total amount of alkaloids of the bark. In terms of a treatment, HCL is suitable as an addiction interrupter and re-conditioning tool, but (imho) lacks the boarder therapeutic effects of the bark, or its total alkaloid extract.