Hi there Kathleen - sorry no-one has responded here ( still holiday period - 9th day of Christmas today!!). I don't think it lasts very long in your system because otherwise the body would not register a drop in prog when used as part of cyclical HRT in order to trigger the withdrawal bleed - so several days I would say. However some of the physiological changes may take a bit longer - I haven't actually looked into this. Also I am not sure whether the progestogen-like metabolites of Tibolone would mitigate against the negative withdrawal effects from the norethisterone to some extent? You wold have to talk to women who done exactly that and judging by the lack of responses maybe there is no-one here who has done that!
I would have thought you would feel the beneficial effects of Tibolone fairly quickly but as there have been so many thread on this recently I would see how other women have felt generally after starting it. There are bound to be a few weeks of adjustment as you change from one to the other but hopefully you would ride out any side effects and feel wonderful! Depending how well the Evorel conti thinned your lining - you might experience a little bleeding - although I would have thought you would already have had spotting if the balance was wrong for you with this HRT?
Sorry I can't be of more help - but hope you manage to come to a decision and more to the point that it works for you
Hurdity x
