The 4 main categories of HRT changes are body, sexual, mental, and reproductive. Within these categories, the mileage of medication will vary from person to person. Some trans girls will get substantial breast growth while others get little or no breast growth at all.
Image is taken from https://en.wikipedia.org/wiki/Transgender_hormone_therapy_(male-to-female)
The changes you might experience as a trans girl on HRT (MTF)
Physical – One of the first things you will notice is your skin starts to get softer and/or smoother, as well as your pores shrinking and less natural oil production. You might also develop a sensitivity to bruising or cuts and a change of the odor of your body, sweat, and/or urine.
You will also start to notice breast buds starting to form on your nipples as well. This can take anywhere from weeks to months to start developing. Your nipples might also start to be more sensitive; all of this is completely normal and part of growing breasts. Your breasts might also grow at different speeds, and having uneven breasts is normality.
“It’s important to note that breast development varies from person to person. Not everyone develops at the same rate and most transgender women who begin hormone therapy after puberty, even after many years of treatment, can only expect to develop an “A” cup or perhaps a small “B” cup. As with all other women, the breasts of transgender women vary in size and shape and will sometimes be uneven with each other. It is usually a good idea to wait until you have been on hormones for at least a year before pursuing breast augmentation surgery.”
More than likely, you will start to lose muscle mass at the start of your transition. If this is a problem or an issue for you, you might want to exercise consistently since that will help retain your amount of muscle.
Your voice more than likely will not change. If you are a person who is going through male puberty and haven’t had a voice drop yet, it could very much affect it since your voice won’t be dropping anymore from testosterone. However, if your voice is already dropped, you will likely not experience much if any voice feminization from estrogen therapy itself. Trans women will commonly pursue vocal feminization or try to feminize their voice because of this.
One of the biggest things that will start to change is fat distribution. You will start to hold your fat as a cis girl does, around the hips, butt, and chest area. Some say losing weight at the start of your transition can be a good idea so that once you start gaining some weight back, it will redistribute in more feminine areas.
You will also more than likely experience fat distribution of your face changing, making your face seem more “full” or softer. “Your eyes and face will also begin to develop a more feminine appearance as the fat under the skin increases and shifts.” It is common for FFS (facial feminization surgery) surgeons to tell you to wait 1-2 years before perusing. It can take many years to get the full development of feminization.
Your hair will also get thinner and take more time before growing back on your body. “Your facial hair may thin a bit and grow slower, but it will rarely go away entirely without electrolysis or laser treatments.” It is common for trans women to pursue electrolysis or laser since they might not get as much hair reduction as they might want, especially facial areas.
Some trans women talk about shoe size or overall height decreasing. This is not because they are getting overall shorter, or the skeleton structure of themselves is changing. It’s more so the muscle mass decreasing and affecting your ligaments in your hands, feet, and vertebrae. Some trans women talk about losing inches, while other trans women don’t notice a change at all.
Emotional – You might start to notice you reacting to feelings or situations differently. It’s common for trans women to report “feeling more” or being more emotional about situations. Overall you will start to feel more in line with how a cis girl would feel or react to a situation. It can take time or therapeutic help to understand and properly understand these new feelings. You might also experience a much greater “range of emotions” that you can experience. “For most people, things usually settle down after a period of time.”
Sexual – NSFW – One of the first things that you might notice when you start HRT is that your spontaneous erections will decrease significantly, and your ability to get erect might stop entirely. “You will, however, still have erotic sensations and be able to orgasm. For those who are concerned about reduced erections, medications such as sildenafil (Viagra) may be helpful.”
Your orgasms might start to feel different, and you might be able to experience multiple orgasms during sex. It is common for trans women to talk about having more of a “full-body” experience during sex. You might also notice a change in your semen; it may start being thinner and taste different.
You will more than likely experience genital atrophy as your penis and testicles need testosterone to keep the tissue healthy. If this is a problem for you, you might want to look into testosterone cream since that keeps the tissue healthy. Atrophy will make your penis and your testicles decrease in size. “Most experts agree that the amount of scrotal skin available for future genital surgery won’t be affected.”
Reproductive health – As I’ve mentioned above, your penis and testicles need testosterone to function properly. If you are a person who wants to have biological children, it would be a good idea to store sperm before starting HRT.
“On the flip side, because feminizing hormone therapy does not always lower sperm count, If you are sexually active with someone who is able to become pregnant, you should always continue to use a birth control method to prevent unwanted pregnancy.”
Hormones are not birth control. If you are having intercourse with a person who can get pregnant, you still need to take precautionary steps such as condoms or contraceptives.
To finish, transitioning can be a liberating time for a trans person to finally have changes in their body that they didn’t experience during their first puberty. This can be a fascinating and invigorating time for many and a critical part of their journey.