Hi Kathleen,
Another interesting question, well done.
According to the most recent Oestrogel leaflet:
'Daily application of 2.5 g or 5 g Oestrogel over a surface area of 400-750 cm2 results in a gradual increase in oestrogen blood levels to steady state after approximately 3-5 days and provides circulating levels of both oestradiol and estrone equivalent in absolute concentrations and in their respective ratio to those obtained during the early-mid follicular phase of the menstrual cycle.
Oestrogel was administered to 17 postmenopausal women once daily on the posterior surface of one arm from wrist to shoulder for 14 consecutive days.
When treatment is stopped, oestradiol and urinary conjugated oestradiol concentrations return to baseline in about 76 hours.'
The molecular action of hormones is very complex, their metabolism in specific tissues vary considerably. The last study on BC has found that HRT can increase the risks for more than 10 years after being stopped, so it seems difficult to answer your question, because how do you quantify ‘leave' or ‘clear my body'? If this means estradiol blood and urine levels, then according to the pharmacokinetic studies provided by the manufacturers/sellers of Oestrogel, it only takes about 76 hours. The study was performed in only 17 women, I haven't read the whole study yet, but it's a very small sample.
Most women who have stopped HRT and reported that symptoms have returned, usually say they came back ‘with a vengeance', but many don't say when that happened. So your question is really interesting. Regarding progestogens, it's likely that each type has different metabolism and elimination rates. I'll have a look later on, I find the whole thing fascinating, thanks for posting!
BeaR.