An interesting thing happened some weeks ago, when I switched from oral to sublingual estradiol, thus significantly increasing my estradiol level. The skin on the underside of my... penis... (pre-op mtf) just where the urethra is hidden (or "raphe" line) got much darker than before, much more pigmented. It's about half inch wide and goes all the length.

Well, in natal female genitals, labia minora tend to get and stay dark either during puberty or during pregnancy, apparently because of heightened sex hormone levels. So it's not suprising the "male" genital skin could darken on estradiol as well... but...

But the most interesting part is that when one looks on a diagram showing the homologues (developmentally coresponding parts) of the female and male genitalia (such as this one: https://bedahunmuh.files.wordpress.com/2010/05/homologues-of-external-genitalia.jpg , NSFW! ), one can see that the very part of the penile skin that got dark in my case is what was supposed to be the labia minora skin! (red in the linked picture)

So I can say that I reached puberty and my labia minora got dark If only they were sitting in a place where they were supposed to be... sigh...

The same thing happened to me after starting SRS. I think there's an old thread around here somewhere, and that someone said it might be due to the skin shrinking. No clue if that's why, but it sorta makes sense. I was glad to know other people had the same thing going on and that nothing was wrong with me

Quote from: Apple on December 06, 2014, 03:55:23 PMIf only they were sitting in a place where they were supposed to be... sigh...

^I hear that!

Its darker even when I pull the skin taut. And very dark when it wrinkles. Just like my female friend's

I also wonder which part of the penile skin will the surgeon use to create the outer surface of labia minora (partial PI). Unless it will be the dark part, I will be dark in the wrong part of my vulva

I think in most styles of the procedure, that skin will be the bottom/back side of your vaginal canal.  The scrotal skin is normally repurposed as labia minora.

Scrotal skin darkened while on HRT. It is now labia minora and partly the entrance of the canal, in my case, and it's still dark. My endo told me that it is normal for a change in pigmentation.

Estrogen=hyperpigmentation, it's totally normal. My areolas (and nipples) always become darker on more E (more freckles too and tan lasts longer), never checked my labia though (I'm post-op)...and i think the reason areolas/nipples become darker is for the infant to better see that part of the breast when breastfeeding...everything is thought of in advance, nature is miraculous, really!