Sammiejane, I would have to agree with the trichologist as I think that has been my experience too. I first had very gradual hair loss when I was in earlyish peri - my periods were coming every 12-20 days and I had huge adrenaline rushes so I assume my oestrogen levels were surging from low to high then back again.
By the time my periods had spread apart by months my hairloss had stopped (but it hadn't grown back). I started on very low HRT (25mcg patches and utrogestan) and very slowly over 2 years worked my way up to 100 patches (poor absorber) and had no additional hairloss. I then doubled my dose to 2x100 patches, which finally raised oestrogen levels to 257 pmol and after a few months introduced testosterone which pushed my levels up to 700 pmol within 10 weeks. A month or so later my hair started to shed in the same pattern (crown and front/sides). I strongly suspect it wasnt't the testosterone per se but the rapid increase in oestrogen levels. Hoping it will subside soon
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Just my view but I would suggest anyone worried about hairloss increases or decreases their oestrogen and testosterone levels very slowly!!