Hormone therapy for trans men (female-to-male, or FTM) typically involves testosterone administration. This is intended to induce the development of masculine secondary sexual characteristics. Here’s a general overview of testosterone therapy for trans men:

1. Administration:
   • Injections: Intramuscular or subcutaneous injections of testosterone are common and might be administered weekly, bi-weekly, or even every 10 days, depending on the specific type and dose.
   • Gels or Patches: Daily application of testosterone gels or patches can be an alternative for those who don’t want injections.
   • Implants or Pellets: These are implanted under the skin and release testosterone slowly over time.
   • Oral Testosterone: Less commonly used because of potential liver-related side effects.
2. Effects and Timeline:
   • 1-3 Months:
     • Menstrual Cycles: Periods usually become lighter and might eventually stop.
     • Voice: The voice might start to deepen.
     • Body Fat: Redistribution might start, particularly from the hips to the abdomen.
     • Libido: An increase in sex drive is common.
     • Skin: The skin can become oilier and acne might develop or worsen.
     • Hair: Facial and body hair might start to grow, while scalp hair might start to thin.
   • 3-6 Months:
     • Voice: Continued deepening.
     • Muscle Mass: Increase in muscle size and strength, especially with exercise.
     • Body and Facial Hair: Continued growth and darkening.
   • 6 Months – 1 Year:
     • Voice: Likely reaches its deepest point during this period.
     • Clitoral Growth: The clitoris might enlarge.
     • Hair: Continued facial and body hair growth.
   • 1 Year and Beyond:
     • Hair: Facial hair may continue to get thicker and body hair growth can continue for up to 5 years or more.
     • Fat Redistribution: This will continue, though the pace might slow down.
     • Muscle: Continued development, especially with exercise.
3. Other Considerations:
   • Infertility: Testosterone can lead to a decrease in fertility. Those wishing to have biological children in the future might consider options like egg or embryo freezing before starting hormone therapy.
   • Cardiovascular and Other Health Risks: As with any medical intervention, there are risks. Regular monitoring by a healthcare provider is crucial to check for potential issues like liver function abnormalities, elevated cholesterol, or high blood pressure.
   • Mood and Emotional Changes: Some individuals report mood swings, irritability, or even changes in emotional processing.
4. Permanent vs. Reversible Changes:
   • Permanent Changes: Voice deepening, clitoral enlargement, and facial/body hair growth.
   • Reversible Changes: Stopping testosterone might reverse changes like fat redistribution, cessation of menstruation, and increased muscle mass, though the timeline and extent can vary.
5. Surgical Options: Some trans men also opt for surgeries like mastectomy (chest/top surgery) or hysterectomy, in addition to, or instead of, hormone therapy.

Starting testosterone therapy is a significant decision and should be made in consultation with knowledgeable medical professionals. Before beginning HRT, individuals typically undergo assessments from mental health professionals to ensure the person is making an informed decision and is ready for the changes that come with HRT.