What causes hot flashes?

Estrogen changes: A drop in estrogen, one of the female hormones, has been shown to be the cause of "hot flashes" of perimenopause.Hot flashes can also be caused by thyroid imbalances, drug interactions, and of course spicy foods.

Decrease in estrogen: Around the "Perimenopause" the ovarian estrogen production is gradually decreasing and this may lead to more or less severe hot flushes that is also associated with other symptoms.

Unknown: The exact mechanism is unknown but it most likely relates to a change in estrogen levels. That is why they are so commonly associated with menopause. There can be other things that trigger hot flashes, like hyperthyroid, so a proper evaluation can often distinguish hormone hot flashes from other sources.