I used progesterone cream from the health food store for years. Emerita was one brand and another, which has since gone out of business, was Bioenteric. I got great relief using it. But my issues were not hot flashes but painful periods, breast soreness, long, heavy periods. And that all improved when I used progesterone cream.
Then, last year I saw a hormone dr. She prescribed progesterone cream. Compounded with a higher dosage of progesterone. Even though my progesterone level wasn't low, because I was having symptoms, she thought we could give it a try. With the higher dose, prescribed cream, I packed on 15lbs in about 6mos. I never had weight issues on the lower dose. In fact, my weight was always ideal and maybe that was the correct dose to keep me from gaining weight. What happened was my estrogen really amped up when the increased levels of progesterone were introduced and then I gained a lot of weight. Still trying to lose about 10lbs of it
I really read a lot about the safety of progesterone. There was one study done years ago about progesterone, but I don't think the progesterone in that study was derived from natural sources like wild yam. And since there is no money to be made by the pharmaceutical companies on progesterone cream, no published studies have been conducted since. But I talked to pharmacists and read a lot and progesterone is pretty safe. Especially in the low dose from over the counter progesterone. There is more information saying it will help protect you from gynecological and breast cancers than cause it. And for the short amount of time you would try or need it, I think you'd be fine.