i also wonder this, too.
i have most of my minoxidil sitting in the medicine cabinet - and the weather lately has been humid of 25+ degrees.
sometimes i wonder if its damaging my minoxidil's integrity and i have a large sum of money invested in large quantities of minoxidil in my medicine cabinet. Don't want it all to go to waste.
Should i place the minixodil in the fridge to protect it from high temperatures?