What testosterone microdosing dosage and regimen is recommended for a female-to-male (FtM) transgender patient?

FtM Testosterone Microdosing Dosage

For FtM transgender patients seeking microdosing or gradual masculinization, start with 25-50 mg testosterone enanthate or cypionate intramuscularly weekly, or 25-50 mg of 5% testosterone cream/gel daily, titrating based on testosterone levels and desired pace of physical changes.

Understanding "Microdosing" in Transgender Care

The term "microdosing" in FtM transgender care refers to using lower-than-standard testosterone doses to achieve slower, more gradual masculinization. This approach is particularly relevant for:

• Non-binary individuals seeking partial masculinization
• Those wanting to control the pace of physical changes
• Patients concerned about rapid virilization

Important context: The available guidelines 1, 2 and FDA labeling 3 focus on cisgender hypogonadal men, not transgender-specific dosing. However, the Endocrine Society transgender guideline 4 provides monitoring frameworks that can be adapted.

Specific Dosing Recommendations

Injectable Testosterone (Enanthate or Cypionate)

Starting microdose range:

• 25-50 mg intramuscularly weekly (compared to standard 75-100 mg weekly for full masculinization) 2
• Alternative: 50-100 mg every 2 weeks for very gradual changes

The standard dose for cisgender men is 75-100 mg weekly or 150-200 mg every 2 weeks 2. Research demonstrates that lower doses still produce masculinizing effects, just more slowly 5.

Key evidence: A 2013 dose-response study 5 showed that 125 mg every 2 weeks (equivalent to ~45 mg weekly) produced therapeutic effects within 6 months, though onset was slower than higher doses. Early physical changes were dose-dependent at 1 month, but by 6 months, all dose groups achieved similar masculinization.

Transdermal Preparations

Testosterone gel/cream:

• Start with 25-50 mg daily (half the standard 50-100 mg dose for cisgender men) 2
• A 2022 study 6 specifically evaluated AndroForte 5% cream in transgender individuals, finding that 53% started at doses <100 mg daily (median 50 mg), achieving median testosterone levels of 11.9 nmol/L

Critical advantage of transdermal: More flexible dose titration in small increments compared to injectable formulations.

Target Testosterone Levels

For microdosing, aim for testosterone levels in the lower-normal male range or upper-normal female range:

• Target: 300-500 ng/dL (10.4-17.4 nmol/L) for gradual masculinization
• Standard FtM therapy targets mid-normal male range: 400-700 ng/dL 1, 4

The Endocrine Society guideline 4 recommends monitoring testosterone every 2-3 months initially, measuring:

• Injectable testosterone: Midway between injections
• Transdermal: Any time after 1 week of use

Monitoring Protocol

Essential monitoring schedule (adapted from 4):

First Year:

• Every 2-3 months: Clinical assessment, testosterone levels, complete blood count, liver function
• Check for desired masculinizing effects: voice deepening, facial hair, menstrual cessation
• Monitor for adverse effects: polycythemia (hematocrit >54%), acne, mood changes

After First Year:

• Every 6-12 months: Same parameters as above
• Estradiol should be <50 pg/mL once amenorrhea achieved 4

Critical safety threshold: Stop therapy if hematocrit exceeds 54% 1, 2, 4. This occurred in only 7% of patients on low-dose testosterone cream 6.

Practical Titration Algorithm

1. Start low: Begin with 25-50 mg weekly (injectable) or 25-50 mg daily (gel)
2. Measure at 6-8 weeks: Check testosterone level and assess early physical changes
3. Adjust in small increments:
   • If testosterone <300 ng/dL and faster changes desired: increase by 12.5-25 mg
   • If testosterone 300-500 ng/dL: maintain dose if pace acceptable
   • If testosterone >700 ng/dL: reduce dose
4. Reassess every 2-3 months until stable, then every 6 months

Formulation-Specific Considerations

Injectable advantages:

• Lower cost
• Proven efficacy 5, 7, 8
• Less frequent administration

Injectable disadvantages:

• Less flexible dose adjustment
• Potential mood fluctuations between injections 1

Transdermal advantages:

• Easier dose titration in small increments
• More stable testosterone levels
• Preferred by many non-binary individuals 6

Transdermal disadvantages:

• Higher cost
• Daily application required
• Risk of transfer to others (must cover application site) 1, 2

Common Pitfalls to Avoid

1. Don't use standard cisgender male dosing for microdosing goals - This defeats the purpose and may cause unwanted rapid changes
2. Don't measure testosterone at wrong times - For injectables, must measure midway between doses, not at peak or trough
3. Don't ignore hematocrit monitoring - Polycythemia risk exists even at lower doses
4. Don't assume one-size-fits-all - Body mass index affects testosterone requirements 9; higher BMI may require dose adjustments

Evidence Quality Note

The strongest evidence comes from the Endocrine Society guidelines for cisgender men 1, 2 and transgender persons 4, but transgender-specific microdosing data is limited to observational studies 6, 5, 7. The 2022 study 6 provides the most direct evidence for low-dose testosterone use in non-binary individuals, showing safety and efficacy at 50 mg daily doses.