Unfortunately, I know all about hot flashes even though I don't really experience them much yet. Sometimes I do get a bit hot and sweaty through the night, even in cool weather with just a top sheet and thin doona on the bed, but not often.
The reason I know about what causes them is the stupidly high amount of research I've done over the past couple of years into specific hormone therapies and their side effects. That's another story, but the following is what I have learnt about hot flashes and how they can be controlled.
Back to basics: Men have testosterone which slowly diminishes over the years. Normal range is 300 to 1000 ng/dL. Over the past year mine has varied between 407 and 537, still in normal range but toward the lower end. This is purely from my age (60) and the natural decline over time. Women have estrogen which falls off a cliff during menopause, and it is this sudden loss of estrogen in their bodies that causes the most common symptom of hot flashes (there are obviously other symptoms as well). Women also have a small amount of testosterone and men also have a small amount of estrogen. In men, the estrogen is actually a by-product of testosterone production. As the testosterone level slowly decreases, so does the level of estrogen, and that is why hot flashes slowly appear in men, particularly in their 60's and 70's. It's not due to a hormone imbalance, because the testosterone and estrogen are still perfectly in proportion to each other, rather it's due to hormone deprivation and the resultant lack of estrogen. It's called MANopause! At least it is gradual though.
Want to get rid of hot flashes? The most obvious thing to do medically is to undertake testosterone replacement therapy, but really, it's just cheating, and denying the body of its natural way. Most men won't experience a total drop off of estrogen like women do, so it's just a case of sucking it up. There are other treatments though. Since the hot flashes are purely driven by a lack of estrogen, you can do what some women do and take an estrogen supplement in the form of an Estrodiol transdermal patch or application of cream on the skin. It is highly effective. What a shame that it will result in feminization of your body!
Less effective, but still worthwhile, are some progesterone products and even some anti-depressants, but both have their own side effects, some of them nasty.
My situation is unique in that I have a medical condition that might eventually need my testosterone to be quickly reduced to castrate levels. My estrogen level will also be quickly minimized as a result, and I can expect severe hot flashes. It is the side effect that I worry about the most. Apart from that, over time my body will go through a de-masculinization process but I will not be able to go on testosterone replacement therapy to help with that or the hot flashes, so I will be looking at one of the other methods if my hot flashes are debilitating enough. Time will tell.