The process of feminization through hormone replacement therapy (HRT) for transgender women (male-to-female) involves the administration of estrogen and often anti-androgens. The changes induced by HRT occur over varying periods, and individual experiences can differ widely. Here’s a general timeline of what one might expect during MTF HRT:

1-3 Months:

  • Skin Changes: The skin often becomes softer and less oily.
  • Body Fat Redistribution: Fat may start to redistribute from the waist to the hips and thighs, but this is a slow process.
  • Breast Development: Tender and swollen nipples or buds might form, indicating the beginning of breast growth.

3-6 Months:

  • Breast Growth: Continued development of breasts.
  • Body Hair: Reduction in the growth rate, density, and coverage of body hair, especially on the chest and back.
  • Facial Hair: Typically, facial hair remains largely unaffected by HRT, although it may soften slightly. Laser hair removal or electrolysis is usually needed to remove facial hair permanently.
  • Muscle Mass: A reduction in muscle mass and strength, particularly in the upper body.
  • Sexual Effects: Spontaneous erections may decrease and overall libido may decrease or change.
  • Mood and Emotions: Some people experience mood swings or emotional changes.

6-12 Months:

  • Hair: The hairline might undergo slight feminization, though this varies between individuals.
  • Nipples: The areolas may expand and become more feminine in appearance.
  • Metabolism: Metabolic rate may decrease, possibly leading to weight gain.

1-2 Years:

  • Body Fat: Continued redistribution of fat to a more feminine pattern, including the face, hips, and buttocks.
  • Breasts: Continued growth, though the pace typically slows. Most transgender women report a cup size of A or B after several years of HRT, but this varies.
  • Facial Changes: Continued softening of facial features due to fat redistribution.

2-5 Years:

  • Breast Development: It can take up to five years (or more) to realize the full growth potential of breasts from HRT alone.
  • Body Fat and Muscle: These changes can continue for several years, with gradual shifts aligning more with cisgender female patterns.

Additional Considerations:

  • Bone Density: Over time, especially without testosterone, there might be some decrease in bone density. This risk increases if estrogen is taken alone without any form of progesterone or testosterone.
  • Fertility: Testicular volume decreases, and there’s a substantial risk of infertility. While many trans women might become infertile after several months on hormones, there are reported cases of pregnancies fathered by transgender women who’ve been on HRT for years. Those considering future biological children should look into sperm banking before starting HRT.
  • Sexual Health: Genital dysphoria might change or evolve, and sexual preferences might expand or shift in some people.

While the above timeline provides a general idea of changes, individual experiences can vary based on genetics, age at which HRT is started, hormone levels, and other factors. Regular check-ups with a healthcare provider are essential to monitor hormone levels and ensure overall health.