Why isn’t progesterone needed when using topical estrogen on the face or vagina, even for people with a uterus?
Topical estrogen that you use on the face or inside the vagina works locally in those tissues. It doesn’t raise estrogen levels in your bloodstream, so it doesn’t stimulate the uterine lining. That’s why progesterone isn’t needed alongside these products, even if you still have a uterus.
Here at Alloy, we lean on the guidance shared by our medical experts. In our webinar on topical estrogen, the doctors explain that low dose vaginal estradiol and estriol face creams don’t reach the uterus in any meaningful way. If estrogen isn’t reaching the uterine lining, there’s nothing for progesterone to balance. You can watch that part of the conversation here in the chapter on common questions and safety:Topical estrogen safety
Progesterone is only needed when someone with a uterus is taking systemic estrogen like pills or patches. Those raise estrogen levels throughout the body, which can thicken the uterine lining. That’s the situation where progesterone is protective.
If you’re using vaginal estradiol or our M4 estriol face cream, you’re just treating the skin or vaginal tissue right where it needs help. No progesterone required.
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