What Is TRT?

Testosterone replacement therapy (TRT) is a medical treatment that restores testosterone levels to a normal physiological range in men who have been clinically diagnosed with hypogonadism — a condition where the body doesn't produce adequate testosterone. TRT is not performance enhancement. It's not bodybuilding-dose steroids. It's a medical intervention designed to bring deficient men back to the normal range, typically targeting total testosterone levels of 500 to 900 ng/dL.

The distinction matters because TRT has become simultaneously overprescribed (by anti-aging clinics targeting men with normal-low testosterone who might benefit more from lifestyle optimization) and stigmatized (by people who equate all testosterone use with illegal steroid abuse). The truth is somewhere in the middle: TRT is a legitimate, evidence-based treatment for clinically low testosterone that can dramatically improve quality of life when properly administered under medical supervision.

When Is TRT Appropriate?

TRT is medically indicated when a man has both low testosterone levels (confirmed by blood work) AND symptoms consistent with hypogonadism. Numbers alone aren't sufficient — a man with total testosterone of 350 ng/dL who feels great and has no symptoms doesn't necessarily need treatment. Conversely, a man at 280 ng/dL with significant symptoms likely benefits from intervention.

Blood work criteria: Most endocrinology guidelines define low testosterone as total testosterone below 300 ng/dL, confirmed on at least two morning blood draws (testosterone is highest in the morning). Some clinicians use a threshold of 350 ng/dL when symptoms are present. Free testosterone (the biologically active fraction) should also be assessed, as total testosterone can be misleadingly normal when SHBG (sex hormone-binding globulin) is elevated.

Symptoms of low testosterone:

  • Reduced libido and sexual desire
  • Erectile dysfunction or reduced erectile quality
  • Persistent fatigue and low energy
  • Loss of muscle mass or difficulty building muscle despite training
  • Increased body fat, particularly abdominal fat
  • Depressed mood, irritability, or cognitive fog
  • Decreased motivation and drive
  • Reduced bone density
  • Poor sleep quality

Before pursuing TRT, ensure you've exhausted lifestyle optimization: adequate sleep (7 to 9 hours), healthy body composition (below 20% body fat), regular resistance training, adequate nutrition (including sufficient fat, zinc, and vitamin D), and stress management. These interventions can raise testosterone by 20 to 40% in men with lifestyle-driven deficiency.

Forms of TRT

Injectable testosterone (most common): Testosterone cypionate or enanthate administered via intramuscular or subcutaneous injection. Typical protocols: 100 to 200mg per week, often split into two injections per week for more stable blood levels. This is the most cost-effective and most controllable form of TRT.

Topical testosterone (gels and creams): Applied daily to the skin (shoulders, upper arms, or inner thigh). Brands include AndroGel, Testim, and compounded creams. Advantages: no injections. Disadvantages: risk of transference to partners or children through skin contact, variable absorption, higher cost, and less precise dosing.

Testosterone pellets: Small testosterone pellets implanted subcutaneously (usually in the hip area) every 3 to 4 months. Provides steady-state levels without daily or weekly dosing. Disadvantages: requires an in-office procedure, difficult to adjust dosing quickly, and risk of pellet extrusion.

Nasal testosterone (Natesto): Applied inside the nostrils 3 times daily. Advantages: rapid absorption, minimal transference risk. Disadvantages: inconvenient dosing frequency, nasal irritation, and limited clinical experience compared to injectables.

What TRT Does

When properly administered to a genuinely hypogonadal man, TRT typically produces noticeable improvements within 3 to 6 months:

  • Muscle mass and strength: Restoration of anabolic signaling increases muscle protein synthesis. Men on TRT typically gain 5 to 10 lbs of lean mass in the first year while losing body fat — even without changes to training or nutrition.
  • Body composition: Fat mass decreases, particularly visceral abdominal fat. Lean mass increases. Overall body composition shifts favorably.
  • Libido and sexual function: One of the first and most noticeable improvements. Increased sexual desire, improved erectile quality and frequency, and enhanced sexual satisfaction.
  • Mood and cognitive function: Reduction in depressive symptoms, improved energy, increased motivation, better memory and concentration. Many men describe a "fog lifting" effect.
  • Bone density: Testosterone supports osteoblast activity (bone formation). Long-term TRT increases bone mineral density, reducing fracture risk — particularly important for aging men.

Risks and Side Effects

TRT is not without risks, and an informed decision requires understanding both the benefits and the potential downsides:

Fertility suppression: Exogenous testosterone suppresses LH and FSH (the hormones that signal sperm production and natural testosterone synthesis). Most men on TRT will experience significantly reduced sperm production. For men who want to maintain fertility, HCG (human chorionic gonadotropin) is often co-administered to maintain testicular function. Discuss this with your physician before starting TRT if future fertility is a consideration.

Erythrocytosis (elevated red blood cells): Testosterone stimulates erythropoiesis (red blood cell production). Elevated hematocrit levels increase blood viscosity and cardiovascular risk if unchecked. Regular blood work monitoring (every 3 to 6 months) is essential. Many TRT patients need to donate blood periodically to manage hematocrit.

Estrogen elevation: Testosterone aromatizes to estradiol. Some men on TRT experience elevated estrogen, leading to water retention, mood changes, or gynecomastia. An aromatase inhibitor (anastrozole) may be prescribed in these cases, though many clinicians now prefer to manage estrogen through TRT dose adjustment rather than adding another medication.

Acne and oily skin: Increased androgen activity can stimulate sebaceous glands, leading to acne — particularly on the back and shoulders. This is typically mild and manageable.

Hair loss acceleration: Men genetically predisposed to male pattern baldness may experience accelerated hair loss on TRT due to increased DHT (dihydrotestosterone) levels.

Cardiovascular risk: The relationship between TRT and cardiovascular risk has been debated extensively. Recent large studies (including the TRAVERSE trial published in 2023) suggest that TRT at replacement doses does not increase cardiovascular events in hypogonadal men with pre-existing cardiovascular risk factors. However, long-term data beyond 5 years remains limited.

Testicular atrophy: Without LH stimulation, the testes decrease in size over time on TRT. HCG co-administration can prevent or minimize this effect.

Monitoring on TRT

Responsible TRT requires regular blood work and physician oversight:

  • Before starting: Comprehensive blood panel including total testosterone, free testosterone, LH, FSH, estradiol, CBC (hematocrit), PSA, lipid panel, and metabolic panel.
  • 6 to 8 weeks after starting (and after dose adjustments): Total testosterone, free testosterone, estradiol, and CBC to assess response and identify early side effects.
  • Every 3 to 6 months ongoing: Full panel including testosterone levels, hematocrit, estradiol, PSA (prostate marker), and lipids.
  • Annually: Comprehensive metabolic panel, DEXA scan (bone density), and cardiovascular risk assessment.

Finding a Provider

TRT should be managed by a physician experienced in hormone therapy. Options include:

  • Endocrinologist: Specialists in hormonal disorders. Often conservative in prescribing but thorough in assessment.
  • Urologist: Particularly appropriate if fertility preservation is a concern.
  • Men's health / TRT clinic: More accessible and often more willing to prescribe, but quality varies. Ensure the clinic performs proper diagnosis (blood work, symptom assessment) rather than prescribing based on marketing alone.
  • Telemedicine TRT services: Increasingly available. Convenient but ensure lab work is performed and physician oversight is genuine, not perfunctory.

Key Takeaways

  • TRT is a legitimate medical treatment for confirmed hypogonadism — not performance enhancement and not something to pursue without proper diagnosis.
  • Before considering TRT, optimize sleep, body composition, training, nutrition, and stress management. These interventions can raise testosterone by 20 to 40%.
  • Injectable testosterone cypionate or enanthate (100 to 200mg/week) is the most common, controllable, and cost-effective form of TRT.
  • Key risks include fertility suppression, elevated hematocrit, estrogen elevation, and accelerated hair loss. All are manageable with proper monitoring.
  • Regular blood work every 3 to 6 months is essential. Never take testosterone without physician oversight and ongoing monitoring.