What is the recommended dose and frequency for testosterone (intramuscular injection) in a female patient when using a 200 mg/ml solution?

Testosterone Injection Dosing for Females

For females requiring testosterone therapy (e.g., gender-affirming care), start with 50 mg of testosterone cypionate or enanthate subcutaneously or intramuscularly weekly, using your 200 mg/ml concentration by drawing 0.25 ml per injection. 1, 2

Recommended Dosing Protocol

Initial Dose and Route

• Start at 50 mg weekly administered either subcutaneously (preferred) or intramuscularly 1, 2
• With a 200 mg/ml concentration, this equals 0.25 ml per injection 1
• Weekly dosing provides more stable testosterone levels compared to biweekly administration 1

Dose Range and Titration

• The effective dose range is 50-150 mg weekly for most patients 1, 2
• Median effective dose in clinical studies was 75-80 mg weekly 2
• Measure testosterone levels at 2-3 months after initiation or any dose change, checking midway between injections 1
• Target mid-normal male range testosterone levels (450-600 ng/dL) 1
• Adjust dose based on serum levels and clinical response 1

Route Selection: Subcutaneous vs Intramuscular

Subcutaneous Administration (Preferred)

• Subcutaneous injection is increasingly preferred due to ease of self-administration, less discomfort, and comparable efficacy to intramuscular 1, 2
• Achieves therapeutic testosterone levels equivalent to IM administration 1
• Effective across a wide BMI range (19.0 to 49.9 kg/m²) 2
• In a study of 63 female-to-male patients, all achieved normal male testosterone levels with SC dosing 2
• Among 22 patients who switched from IM to SC, 20 had marked preference for SC and none preferred IM 2
• Minor and transient local reactions occurred in only 9 out of 63 patients (14%) 2

Intramuscular Administration

• Ventrogluteal or anterolateral thigh are the recommended IM injection sites 1
• Use 21-23 gauge, 1-1.5 inch needles for IM injection 1
• Longer needles (1.5 inch) typically needed for gluteal injections, shorter (1 inch) may suffice for thigh injections in leaner patients 1

Dose-Response Considerations

Early Treatment Effects

• Higher initial doses produce faster onset of masculinizing effects (voice deepening, facial hair, cessation of menses) within the first month 3
• However, by 6 months, all doses (125 mg every 2 weeks, 250 mg every 2-3 weeks) were equally effective 3
• This suggests starting with moderate doses (50 mg weekly) is reasonable, as therapeutic effects will be achieved within 6 months regardless 3

Monitoring Schedule

• Check testosterone levels at 2-3 months after initiation or dose changes 1
• Once stable levels achieved, monitor every 6-12 months 1
• Monitor for erythrocytosis, which occurs more frequently with injectable formulations 1

Practical Administration Details

Supplies Needed (per injection)

• 18-gauge needle for drawing from vial 1
• 21-23 gauge, 1-1.5 inch needle for injection 1
• 1-3 ml syringe (1 ml adequate for 50 mg dose) 1
• Alcohol prep pads 1
• Gauze pads or cotton balls 1
• Adhesive bandages 1
• Sharps container for safe disposal 1

Calculation for Your 200 mg/ml Concentration

• 50 mg dose = 0.25 ml
• 75 mg dose = 0.375 ml
• 100 mg dose = 0.5 ml
• 125 mg dose = 0.625 ml
• 150 mg dose = 0.75 ml

Important Caveats

What This Evidence Does NOT Address

• The provided guidelines focus primarily on male hypogonadism and gender-affirming care for transgender patients 1, 3, 2
• Evidence for testosterone therapy in cisgender females with low libido uses much lower doses (transdermal spray delivering approximately 0.5-1 mg daily) 4
• If prescribing for female sexual dysfunction rather than gender-affirming care, this dosing is inappropriate and you should use transdermal formulations at much lower doses 4

Safety Monitoring

• Injectable testosterone may carry greater cardiovascular risk compared to transdermal preparations 1
• Erythrocytosis occurs more frequently with injectable formulations 1
• Assess cardiovascular risk factors before initiating therapy 1

Alternative Formulations

• If injectable testosterone is not suitable, transdermal gel (50-100 mg daily) is an alternative, though this is typically used in males 1
• For cisgender females with sexual dysfunction, transdermal spray at much lower doses (90 μL delivering ~0.5 mg) is more appropriate 4