Apologies it was 35 degrees, not 30 - an excerpt from the study is below. But yes still valid, pastie supper! I used to think about it regarding sunbathing too.
"Design and methods: Estraderm MX 50 mu g, Systen 50 mu g and Oesclim 25 mu g matrix patches were cut into eight pieces while Estradot 50 mu g small patches were cut in half. The cut patches were stored in their respective pouches at +21 degrees C or at +35 degrees C for up to 1 month. The estradiol drug was extracted from the patch by ethyl acetate n-hexane and determined by radioimmunoassay.
Results: Storage at +21 degrees C or +35 degrees C up to 1 month did not reduce the estradiol concentration in Estraderm MX, Systen and Oesclim patches. However, although the estradiol in Estradot patches was not affected by storage at +21 degrees C, at +35 degrees C, estradiol decreased by 57% (+/- 1%) in cut pieces."
I previously took Estradot before switching to Evorel and I also absorbed MUCH more from the Estradot, matching what I've seen many women on the forum say.
it is an odd thing about the oral to transdermal equivalents, considering the difference in advice is literally double!