Susan's Place Transgender Resources

Hi everyone.

I've seen conflicting information in regards to breast growth timelines. Some say they are done by 2-3 years where others say 5-10 years as they report additional breast growth even after the 2-3 year mark.

Obviously it varies from person to person but on average what would you assume would be the normal length of growth time?

I'm curious because I've been on Hormones for nearly 8 months and am currently a small B moving upto a normal B. If growth takes that long could a C or even D cup be plausible?

Thankyou :) xx

It varies with the person, their genetics, and the HRT protocol.

It takes natal girls a decade or more.  Of course, they are fun to play with most any time.  ;)

My breasts became this size after three weeks on full dose HRT. They haven't grown a millimeter in the eight months since.

Well, at 4 years, mine required a mammogram which found something they were suspicious about.  They punctured a hole and let some air out. (ok really a tiny piece of tissue). No cancer!!  Big sigh of relief, if they are big enough to cause that issue, I am backing off on my wish list.  I have a bit of growth from time to time offset by a bit of shrink in my bra's about the same time, but I am bigger than one sister made it, and about even with the other one at 3 years.  I am at 4 years and 8 months with nice full B cups that look better than the ones on other girls my age!!  Mine aren't sagging!!

Well, they don't say to compare you cup size to your relatives for nothing.  What I've always heard is "you should expect to be one cup size below your mother/sister(s)" but of course ymmv.  Tbh, after starting at 18 4 years ago, mine are just slightly smaller than my mother's and larger than my younger sister's (who is currently at the tail end of puberty).  So, what your immediate relatives have is probably a good guideline.

As for when you'll be done.  I'm still getting some growth even now, but it's minimal, most of it was done within the first 2-3 years for me.  But yet again with the immediate growth, I only just started adding progesterone injections a few months ago as I switched endocrinologists (progesterone has a role in breast development due to milk duct formation).

Anyway, thing is though, just like the rest of your measurements, you can't forget that breast size ain't static either.  If you're on progesterone, you'll notice your breasts changing in cycles most likely.  Also, if you have more body fat, you can expect them to grow, while if you lose it, they'll tend to shrink.  Breasts are mostly made of fat deposits after all.

So yes, based on all of that, I think it's plausible, but everyone's different, and you get what you get ofc.  There's always the option of implants if you can afford em anyway :v.

Cis girls' puberty is probably a good guideline (since we're effectively doing the same thing, just later), and it's anywhere from 5-10 years for them. As for a personal anecdote, four years for me next month and I'm 42DDD and still growing, albeit more slowly. My mom's a tiny skinny 34B, but my paternal aunt has the same body type I do, big-breasted and not skinny. So I don't buy that "cup size smaller than mother/sister" thing either; clearly it can vary. :) It's all genetics, and sometimes genes skip a generation or come from the other side.

It's very hard to predict the finishing point because growth rates vary, too. I grew very fast early on but more slowly since; some women grow slowly throughout but after 10 years are quite large, and so on. The lesson seems to be that our final size is in our genes, just like for cis girls, and we'll get there when we get there, so (as annoying as it is), the only real option is patience.

I started HRT at 17 and continued to develop for more than 10 years. Through the additional 30 years, my cup size continued to increase but only about 1 more cup size. Last year I took as course of progesterone (a sort-of hormonal pregnancy) and gained another 1.5 cup size. Frankly my breasts never really looked "mature" until after the progesterone.

Just using the Tanner "puberty chart" here, and the average age that cis-girls usually reach each stage at:

Tanner II (nipple buds): 10.9 years old
Tanner III (beginning of soft tissue formation): 11.9 years old
Tanner IV ("mound on a mound" phase): 12.9 years old
Tanner V (adult shape): 14.3 years old

So translate that to a trans woman, and here's about what you would get if you went through your second "puberty" at the same rate as a cis-girl: (note, though, that because we're going through this puberty later in life, it takes us a bit longer, and might not be as complete. I've read that a majority of trans women have a difficult time making it to Tanner V.)
Tanner II: after 3-6 weeks on hormones
Tanner III: after about 1 year on hormones
Tanner IV: after about 2 years on hormones
Tanner V: after about 3.5 years on hormones

Personal experience:
Still growing... I hit what looked like "Tanner III" growth at about the 7-month mark, and they've still been in the process of slowly rounding ever since then. I still have a long way to go.

(The odd thing about the Tanner stages for me has been that it describes my growth *cycle* rather than actual progression... as in, I'll find the buds noticeable/sore, then things soften a bit, then I see the nipple/areola stand out from the breast, then it looks soft and rounded, and then things started over from step 1! I guess mine are weird? However, I've been seeing nothing but gradual fat deposit and rounding for the last few months, so I think maybe they're entering the finishing-touches stage [which can still take a while, I hear].)

In my experience the guide that you will be  one cup size smaller than your sister or mother is not true. My sisters  one is a C one is a D. I am a G cup.