Estring, for example, releases over 90 days an amount equivalent to taking oral
estrogen for just 2 days,
and Vagifem, aready a very low dose
estrogen product, is now available
in a 10 mcg dose, as well as the original 20 mcg dose. (Both of these are reported to be preferrable to a similar third product, Estrace.) These products also appear to have a very, very low level of systemic absorption.