I gauge my dose by my main symptoms- e.g. the return of hot flushes at night, joint pain, and other symptoms are my guide that my oestrogen has dropped. On the other hand, when I swapped patches from Estradot to Evorel back in June, I kept getting visual migraine auras which are a sign of high oestrogen. My GP agreed that I must absorb oestrogen better from the Evorel patches, and when I dropped a dose the migraine auras disappeared.