Testosterone is the hormone that is responsible for libido (sex drive) and primarily responsible for sexual response as well. We always think of it as a male hormone but we women have it too, just in lower amounts.
I'm using a 1% compounded natural testosterone gel now. You can also get it in a cream form. Both are available by prescription from a compounding pharmacist. The commercially available products you may see on line are prepared in concentrations required by men and are too strong for us to use; most of them are not natural testosterone but are synthetic modified androgens which can be many times more powerful than natural testosterone and also can break down in the body into byproducts which can cause us undesirable and unnecessary side effects.
The transdermal testosterone is applied to the vulva, and is very helpful for reversing vaginal atrophy and urethral atrophy as well as eliminating vaginal dryness. It takes a while to build up an effect on libido (for me it took two weeks) but it does work to restore sex drive to a normal (in my case better than pre-op) level. Also if you do your kegels, it can help reduce urinary incontinence by building muscle mass in the pelvic floor muscles. For many women, it gives us an increased energy level and a feeling of being "ourselves" again where estrogen and/or progesterone didn't quite do that.
So, what is the downside? For one thing, a little testosterone is a wonderful thing, if you need it (I would recommend having your serum free testosterone level tested before trying it) and a lot of testosterone is a very bad thing. You can get all kinds of nasty side effects like acne, facial and body hair, male pattern baldness, deepening voice, even enlarged clitoris... need I go on here? So, be careful, don't try it without your DR's OK.
Also, for those who absolutely, positively can't have even the tiniest bit of estrogen, it's a bit risky because your body can convert testosterone to estradiol. If you want to try it and you fall into this category I'd recommend having your estradiol level checked beforehand (at the same time as you have your free testosterone level checked) and then again after you've been using it for a while to see if you are indeed making any estradiol from it.
I hope this helps... testosterone is wonderful for some ladies (I am one of those) but not for everyone.