How to Start TRT: Step-by-Step Protocol for Safe Testosterone Therapy

Written by Adam Maggio | Medically reviewed by Dr. Mitchell Ross, MD, ABAARM

Begin TRT only after confirming total testosterone below 300 ng/dL via morning labs. Start intramuscular testosterone cypionate at 100mg weekly, monitor labs at 6 weeks, and adjust dosing based on symptomatic response and serum testosterone.

Testosterone Levels and Diagnosis

Studies show that over 40% of men over 45 report symptoms consistent with low testosterone, yet only a fraction get diagnosed. Clinically, a total testosterone (TT) level below 300 ng/dL on two separate morning draws is diagnostic for hypogonadism. Morning blood samples between 7-10am are critical because testosterone follows circadian rhythm, peaking early and falling later.

Step 1: Baseline Evaluation and Lab Testing

Start by obtaining a thorough clinical history assessing symptoms like fatigue, reduced libido, and mood changes. Then, order these labs:

TRT shouldn’t start without ruling out treatable secondary causes such as pituitary dysfunction or medication-induced hypogonadism.

Step 2: Choosing Your Testosterone Formulation and Dose

Testosterone cypionate and enanthate are the most studied injectable esters. Evidence suggests starting testosterone cypionate at 100mg intramuscularly every 7 days balances symptom relief and side effect minimization better than 200mg biweekly injections, which can cause supraphysiologic peaks and troughs (Morgentaler, 2019).

Alternatively, testosterone gels dosed at 50-100mg daily achieve steady-state levels but have variable absorption and risk of transference to close contacts.

For convenience and uniformity of absorption, injections remain the gold standard during initiation. Undecanoate injections can be dosed every 10-14 weeks but require more monitoring during startup phases.

Step 3: Monitoring During the First 6-12 Weeks

Check serum total testosterone 5 days post-injection to capture mid-cycle troughs. Target serum TT between 450-650 ng/dL for optimal symptom relief without excessive risks (Bhasin et al., Endocrine Society Guidelines, 2018).

Monitor hematocrit; levels above 54% increase thrombosis risk. If elevated, reduce dose or increase injection frequency to smooth levels.

Watch for side effects like increased PSA, erythrocytosis, acne, and mood swings. Adjust dose accordingly.

Step 4: Dose Adjustments Based on Clinical and Lab Data

If testosterone levels remain below 400 ng/dL with persistent symptoms, increase dose by 25-50mg weekly increments. If hematocrit rises above 54% or side effects appear, consider reducing dose or shifting to weekly injections rather than biweekly.

Some men metabolize testosterone faster due to genetic polymorphisms in CYP enzymes; these patients may need higher or more frequent dosing.

Step 5: Long-Term Monitoring and Management

TRT vs Natural Testosterone Boosters

Unlike natural boosters (e.g., D-aspartic acid or Tribulus terrestris) which lack robust clinical efficacy, TRT provides direct hormone replacement, resulting in consistent symptomatic improvement. Natural supplements may benefit mild borderline cases but rarely achieve substantial increases in testosterone or symptom reversal.

Clinical Takeaway

Begin TRT only after confirming low serum testosterone levels below 300 ng/dL on repeated morning labs, preferably before 10am. Initiate testosterone cypionate at 100mg IM weekly, check serum testosterone 5 days after injection at 6 weeks, and adjust dose based on symptomatic improvement and lab results aiming for 450-650 ng/dL. Monitor hematocrit closely to avoid erythrocytosis, and individualize dose adjustments for metabolism variations. This protocol ensures safe, effective testosterone replacement with minimized risks.