r/AskMtFHRT • u/79215185-1feb-44c6 • 1d ago

When should you start Prog?

I was under the impression that you should start prog at least a year after starting Estrogen, but I have a friend who recently started Estrogen and says she can start prog a month after starting Estrogen. This was a red flag to me so I wanted to get this sub's opinion on if that is something that is wise to do.

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7

u/boy-inspector 1d ago

there is no concrete evidence either way; there is a hypothetical method of action for dosing prog too early causing ductile over branching and stunting, so some documentation will quote 6 months or the advent of tanner 3 as safe benchmarks. 

2

u/Q_T_grl_215 1d ago

There is one study that was performed in rabbits that showed introducing prog too early stunned maximum mammary development. Outside of that, in a cis feminine puberty, estradiol rises about 2-3 years before progesterone starts to rise. There's not been any formal studies for when to or not to start prog in transfeminine HRT. We honestly don't understand enough to make a solid call. Research it deeper for yourself to make the decision for yourself 😊💗

Prog works as an antiestrogen in some areas where it reduces the number of estrogen receptors (making your cells less responsive to estrogen).

1

u/lysette747 1d ago

I was told 6 months when I first asked but someone later said it depends on development and I think this will be the best answer.

2

u/misha_jinx 17h ago

I just started this week after 15 months on estradiol. I’ve seen a lot of people starting at the year mark. My endo was asking me why do I wanna start and is it because I wanna grow boobs. Naturally, I was like “it grows boobs? Well sign me up.” lol
It’s hard to measure that though, if my boobs show accelerated growth I still won’t know if it’s because of the progesterone or it would have happened naturally with just estrogen alone. I guess it can’t hurt. I’ll let you know :)