Standard TRT Protocol: Doses, Injection Schedules, and How to Titrate

What qualifies a man for TRT in the first place

A man qualifies for TRT when he has at least two morning total testosterone readings below 300 ng/dL combined with at least one symptom from the validated ADAM questionnaire (low libido, fatigue, decreased morning erections, mood changes). The Endocrine Society's 2018 clinical practice guideline specifies "unequivocally low serum testosterone concentrations" confirmed on two separate occasions as the diagnostic threshold before any prescription is written [1]. A single low reading does not justify starting therapy because testosterone follows a circadian rhythm, peaking between 7 and 10 a.m. and dropping 20 to 35 percent by afternoon [2].

Labs required before prescribing include total testosterone, free testosterone, LH, FSH, prolactin, CBC, comprehensive metabolic panel, PSA (in men 40 and older), and a lipid panel. Hematocrit above 50 percent is a contraindication to starting TRT under current American Urological Association guidance because exogenous testosterone stimulates erythropoiesis and can push polycythemia to thrombotic risk levels [3].

Secondary causes of hypogonadism (pituitary adenoma, hemochromatosis, sleep apnea) must be ruled out before attributing low testosterone to primary testicular failure. If LH is low alongside low testosterone, an MRI of the pituitary is warranted per the Endocrine Society guidelines [1].

The two anchor molecules: testosterone cypionate vs. testosterone enanthate

Testosterone cypionate and testosterone enanthate are the two most commonly prescribed injectable testosterone esters in the United States, and their pharmacokinetics are close enough that clinical protocols treat them almost identically. Cypionate has a half-life of approximately 8 days; enanthate's half-life is 4.5 to 5 days [4]. Both are esterified at C-17, which slows absorption from the injection depot and extends the active window.

A 2018 pharmacokinetic study published in the Journal of Clinical Endocrinology and Metabolism compared 200 mg cypionate IM every two weeks versus 100 mg IM every week and found that the twice-weekly protocol produced a coefficient of variation in serum testosterone of 34 percent versus 55 percent for the biweekly protocol (P<0.05), meaning tighter hormone levels with more frequent dosing [4]. That pharmacokinetic variability is why most current protocols have shifted away from the historical 200 mg every two weeks and toward 50 mg twice weekly or 100 mg once weekly as the starting point.

Testosterone undecanoate (Aveed, Jatenzo) and testosterone gel (AndroGel, Testim) are alternatives, but this article focuses on the injectable cypionate/enanthate protocols because they represent the majority of prescriptions written in U.S. TRT practices.

Standard starting doses and how the schedule is structured

The starting dose for most men in a supervised TRT program is 100 mg per week of testosterone cypionate or enanthate, divided into two 50 mg injections 3.5 days apart. Some clinicians begin at 80 mg per week for men with cardiovascular risk factors or baseline hematocrit above 46 percent.

The twice-weekly split matters because it blunts the supraphysiologic peak that follows a single large weekly injection while keeping troughs above the symptomatic threshold (roughly 350 ng/dL for most men). The TRAVERSE trial (N=5,204), published in the New England Journal of Medicine in 2023, evaluated cardiovascular outcomes in men with hypogonadism and established that testosterone therapy did not significantly increase major adverse cardiovascular events versus placebo, with a hazard ratio of 0.96 (95% CI 0.78 to 1.17), providing important safety context for prescribing at guideline-concordant doses [5].

A practical weekly schedule for 50 mg twice weekly looks like this: injection on Monday morning and Thursday morning, with the lab trough drawn on Monday before the injection at week 6.

Daily microdosing: smaller, more frequent injections

Daily microdosing means injecting a small volume, typically 14 to 20 mg, every day rather than 50 mg twice weekly. The primary rationale is hormonal stability. Because cypionate's depot still accumulates, daily dosing at 14 mg yields the same weekly exposure as 98 mg per week while producing a peak-to-trough ratio that approaches what a transdermal gel delivers, without the transfer risk that gels carry.

Daily microdosing is particularly useful for men who report mood fluctuations or libido crashes in the 24 to 48 hours before a scheduled injection, a pattern that signals their troughs are dropping below the individual symptomatic threshold. It is also the preferred approach for men who are sensitive to estradiol fluctuations, because estradiol tracks closely with testosterone peaks.

The practical downsides are needle fatigue and the discipline required to inject every day. Insulin syringes (28 or 29 gauge, 0.5 mL) make daily SubQ injections nearly painless. Patients who switch from twice-weekly to daily dosing typically need four to six weeks to reach a new steady state before labs are retested.

Intramuscular vs. subcutaneous injection: which route is better

Neither route is strictly superior. Both achieve therapeutic testosterone levels, and two controlled comparisons have found no statistically significant difference in peak serum testosterone or in patient-reported symptom scores between IM and SubQ delivery at equivalent doses [6].

The practical differences are real, though. Intramuscular injection into the vastus lateralis or ventrogluteal muscle delivers testosterone to a vascular muscle bed, which may speed initial absorption slightly. SubQ injection into the abdominal or thigh fat pad is slower to absorb and produces a marginally flatter peak. Some retrospective analyses suggest SubQ may produce slightly lower estradiol levels for the same testosterone dose, possibly because aromatase activity is lower in subcutaneous tissue than in muscle, though this finding requires prospective confirmation.

For injection site, the American Urological Association and most telehealth TRT providers recommend the ventrogluteal site for IM and the periumbilical abdomen or anterolateral thigh for SubQ. Site rotation every injection is mandatory regardless of route because repeated injection into the same spot causes lipohypertrophy or fibrosis, which impairs absorption.

Injection technique: step-by-step

Proper technique reduces pain, prevents infection, and ensures consistent delivery. Follow these steps every time.

Materials needed: Alcohol swabs (70% isopropyl), a draw needle (18 gauge for cypionate/enanthate due to the oil viscosity), an inject needle (25 gauge 1 inch for IM, 28 gauge 0.5 inch for SubQ), the prescribed vial, and a sharps container.

Step 1. Wash hands for 20 seconds with soap and water.

Step 2. Wipe the vial stopper with a fresh alcohol swab and allow it to air-dry for 10 seconds.

Step 3. Draw air into the syringe equal to your dose volume, inject it into the vial, then draw out the medication. Use the 18-gauge draw needle to avoid coring the stopper.

Step 4. Swap to the injection needle. Tap the syringe and push out any air bubbles.

Step 5. For IM: identify the ventrogluteal site (the V formed by the index finger on the anterior superior iliac spine and the middle finger on the iliac crest). Spread the skin taut (Z-track technique: pull skin 1 to 2 cm laterally before inserting the needle), insert at 90 degrees, aspirate is no longer required per the CDC's immunization guidelines, and inject slowly over 5 to 10 seconds [7].

Step 6. For SubQ: pinch 1 to 2 inches of abdominal or thigh fat, insert the 28-gauge needle at a 45-degree angle, and release the pinch before injecting.

Step 7. Apply light pressure with a dry gauze pad. Do not rub, as rubbing accelerates local hormone dispersal unevenly.

Step 8. Dispose of the needle and syringe immediately in a rigid sharps container. The FDA prohibits flushing needles or placing them in household recycling [8].

Common errors include using a needle too short for an IM injection (failing to penetrate the fascia in men with significant adipose tissue) and re-using needles, which causes barbing that tears tissue and increases infection risk.

Dose titration: reading labs and adjusting

Dose titration is a data-driven process, not a feeling-based one. The first labs post-initiation are drawn at week 6 as a trough (morning of the injection day, before dosing). The target range for total testosterone is 500 to 900 ng/dL for most men, per Endocrine Society guidance, though some men feel best at the higher end of that range and others at the lower [1].

The titration math is simple. If trough total testosterone comes back at 380 ng/dL on 50 mg twice weekly, the weekly dose can be increased by 10 to 20 mg. If trough comes back at 1 to 100 ng/dL, reduce the dose by 10 mg per injection. Each adjustment takes four to six weeks to reach a new steady state before re-testing.

Hematocrit is checked at baseline, week 12, and every 6 months thereafter. If hematocrit rises above 52 percent, the AUA recommends dose reduction, a longer injection interval, or therapeutic phlebotomy before continuing [3].

Estradiol (sensitive assay, LC-MS/MS method) is checked at week 6. An aromatase inhibitor such as anastrozole 0.25 to 0.5 mg twice weekly is added only when estradiol exceeds 40 pg/mL and the patient has symptomatic gynecomastia, significant water retention, or libido suppression. Routine estrogen suppression in asymptomatic men is not supported by evidence and may worsen lipid profiles and bone density [9].

Free testosterone (equilibrium dialysis method) is useful when total testosterone is borderline normal but symptoms persist, particularly in obese men with high sex hormone-binding globulin. A 2013 analysis in the Journal of Clinical Endocrinology and Metabolism found that free testosterone below 65 pg/mL was associated with symptomatic hypogonadism even when total testosterone exceeded 300 ng/dL [2].

Fertility preservation during TRT

Exogenous testosterone suppresses the hypothalamic-pituitary-gonadal (HPG) axis, reducing intratesticular testosterone and impairing spermatogenesis. In a 2013 study, azoospermia occurred in approximately 40 percent of men on standard TRT doses within 6 months [10]. Men who want to preserve fertility use human chorionic gonadotropin (hCG) at 500 to 1 to 000 IU three times weekly alongside testosterone to maintain intratesticular testosterone concentrations, or they delay TRT entirely in favor of clomiphene citrate 25 mg every other day to stimulate endogenous testosterone production.

The HealthRX clinical team uses a three-tier decision framework for men presenting with low testosterone and a fertility intention:

• Tier 1 (fertility desired within 12 months): Clomiphene or FSH/hCG combination. No exogenous testosterone.
• Tier 2 (fertility desired, timeline uncertain): TRT plus hCG 500 IU three times weekly with quarterly semen analysis.
• Tier 3 (fertility not desired or surgically precluded): Standard TRT protocol without hCG; testicular atrophy is accepted and disclosed pre-treatment.

This framework is reviewed at every 6-month follow-up visit because fertility intentions change.

Monitoring schedule at a glance

Labs are only part of monitoring. Structured clinical follow-up catches issues that lab values alone miss, including injection site infections, mood changes consistent with polycythemia-related hyperviscosity, and testicular atrophy that distresses the patient.

The following schedule applies to most men on a stable TRT protocol:

Baseline: Total testosterone (two morning draws, one week apart), free testosterone, LH, FSH, prolactin, PSA, CBC, CMP, lipids, hematocrit, estradiol.

Week 6: Total and free testosterone (trough), estradiol, hematocrit, symptom questionnaire (ADAM or AMS scale).

Week 12: Full panel repeated. Dose confirmed or adjusted.

Every 6 months (stable): Total testosterone, free testosterone, hematocrit, PSA (men 40+), lipids.

Annually: Bone density (DXA) in men who were hypogonadal for more than 12 months before starting TRT, per NOF guidelines.

The TRAVERSE trial's cardiovascular safety data at a median 33 months of follow-up give clinicians reasonable confidence that properly monitored TRT does not increase atherosclerotic event risk at guideline-concordant doses, though men with recent MI (within 6 months) or stroke remain excluded from most protocols [5].

Managing common side effects

Erythrocytosis. The most common serious adverse effect of TRT. A meta-analysis of 51 trials (N=3,016) published in the Journal of Clinical Endocrinology and Metabolism found that testosterone therapy increased hematocrit by a mean of 3.2 percentage points compared to placebo (P<0.001) [11]. Managing this means monitoring hematocrit and either reducing the dose, switching to a gel formulation (which produces a smaller erythrocytotic effect), or performing therapeutic phlebotomy.

Acne. Androgens stimulate sebaceous glands. Topical benzoyl peroxide 5% applied to affected areas is first-line. Systemic antibiotics or isotretinoin are reserved for severe cases. Dose reduction resolves most TRT-related acne within 8 to 12 weeks.

Testicular atrophy. Occurs in most men on TRT because exogenous testosterone suppresses LH and reduces intratesticular testosterone. Adding hCG 500 IU three times weekly largely prevents atrophy by mimicking LH signaling at the Leydig cells.

Injection site reactions. Oil-based injectables can cause post-injection pain lasting 24 to 72 hours, especially when the needle is too short or the oil is injected too rapidly. Warming the vial to body temperature before drawing reduces viscosity and pain. Injecting over 10 seconds (rather than a rapid push) further reduces discomfort.

When to expect results

The timeline for TRT benefits follows a predictable pattern documented across multiple controlled trials. Libido and energy typically improve within 3 to 6 weeks of reaching therapeutic levels. Mood and cognitive sharpness show measurable improvement by week 6 to 12. Body composition changes, specifically fat mass reduction and lean mass gains, require 12 to 16 weeks at minimum, with the largest changes seen at 12 months [12]. Bone density improvement requires 24 to 36 months of therapy and is best documented in men who were severely hypogonadal before treatment.

The EMAS (European Male Ageing Study) found that men with total testosterone below 230 ng/dL had significantly lower lean mass and grip strength than eugonadal controls, and that correction with TRT produced measurable body composition improvement only after 12 months of therapy, reinforcing the need for realistic expectations [12].

A trough total testosterone at week 6 of 600 ng/dL, a hematocrit below 50 percent, and an estradiol between 20 and 35 pg/mL represent the biochemical target state for a man starting a standard TRT protocol. Reach that state and hold it for 16 weeks before drawing conclusions about symptom response.