What is the recommended topical dose of testosterone (T) for men requiring testosterone replacement therapy (TRT)?

Topical Testosterone Dosing for Men

For men requiring testosterone replacement therapy, start with testosterone gel 1.62% at 40.5 mg daily (2 pump actuations or one 40.5 mg packet) applied to the shoulders and upper arms, or testosterone gel 1% at 50 mg daily, with dose titration based on serum levels measured at 2-3 months. 1, 2, 3

Initial Dosing Recommendations

Testosterone Gel 1.62% (Preferred Concentration)

• Starting dose: 40.5 mg of testosterone daily (2 pump actuations or one 40.5 mg packet) applied once in the morning 1, 3
• Apply to clean, dry, intact skin of the shoulders and upper arms only 3
• Do not apply to abdomen, genitals, chest, armpits, or knees 3
• The gel dries in less than 5 minutes and should be allowed to dry completely before dressing 3, 4

Testosterone Gel 1% (Alternative Formulation)

• Starting dose: 50-100 mg daily (AndroGel 1%) 5, 1, 2
• Applied to the same anatomical sites as the 1.62% formulation 5

Dose Adjustment Range

• Minimum dose: 20.25 mg daily (1 pump actuation) 1, 3
• Maximum dose: 81 mg daily (4 pump actuations or two 40.5 mg packets) 1, 3
• Dose titration should be based on pre-dose morning serum testosterone measured at approximately 14 days and 28 days after starting treatment 1, 3

Monitoring and Titration Protocol

Initial Monitoring

• Measure testosterone levels at 2-3 months after treatment initiation or any dose change 5, 1, 2
• For transdermal preparations, levels can be measured at any time, though peak values occur 6-8 hours after application 5
• Target mid-normal testosterone levels of 450-600 ng/dL 1, 2

Ongoing Monitoring

• Once stable levels are achieved, monitor every 6-12 months 5, 1, 2
• Monitor hematocrit/hemoglobin, PSA, and lipid profiles periodically 5, 2

Application Technique and Safety

Critical Application Instructions

• Wash hands immediately with soap and water after application 3
• Cover application sites with clothing after the gel has dried 3
• Wash application site thoroughly with soap and water before any skin-to-skin contact with others 3
• Avoid showering, swimming, or bathing for at least 2 hours after application 3

Secondary Exposure Prevention

The FDA requires a boxed warning about secondary exposure to testosterone gel, as virilization has been reported in children who were secondarily exposed 3. This is a critical safety concern that distinguishes topical from injectable formulations. Children and women must avoid contact with unwashed or unclothed application sites 3.

Comparison with Injectable Formulations

While the question specifically asks about topical dosing, it's important to note that injectable testosterone (enanthate or cypionate) at 50-100 mg weekly provides more stable testosterone levels than topical preparations 1, 2. However, topical formulations offer advantages including:

• Easy application and good skin tolerability (except patches, which cause skin reactions in 66% of users) 5, 2, 6
• Avoidance of intramuscular injection discomfort 5
• More consistent day-to-day levels compared to biweekly injections 5

The main disadvantage is higher cost compared to injectable formulations (annual cost $2,135 for transdermal vs. $156 for intramuscular per Medicare data) 5 and potential for transfer to others 5, 2.

Efficacy Evidence

Studies demonstrate that transdermal testosterone gel at these doses effectively:

• Improves sexual function and mood within 30 days 6
• Increases lean body mass by 1.28-2.74 kg at 90 days (dose-dependent) 6
• Decreases fat mass by 0.90-1.05 kg 6
• Increases muscle strength by 11-13 kg in leg press exercises 6

Common Pitfalls to Avoid

Erythrocytosis Risk

Topical preparations have significantly lower risk of erythrocytosis compared to injections (15.4% with transdermal patches vs. 43.8% with intramuscular injections) 5. However, dose-dependent risk exists: 2.8% at 5 mg/day delivered, increasing to 17.9% at 10 mg/day delivered 5. Monitor hematocrit and reduce dose or withhold therapy if elevation occurs 5, 2.

Application Site Errors

Do not apply to the abdomen, genitals, or other non-approved sites, as this can result in inconsistent absorption and different systemic exposure 3. The FDA label specifically restricts application to shoulders and upper arms only 3.

Inadequate Dose Titration

Approximately 76% of patients achieve target testosterone levels with initial dosing 7, meaning roughly one-quarter require dose adjustment. Do not assume the starting dose is adequate without measuring serum levels at 2-3 months 1, 2.

Fire Hazard

Testosterone gel is flammable until dry 3. Patients must let the gel dry completely before smoking or going near open flames 3.