TRT is the right move when your symptoms (fatigue, low libido, poor recovery, fog, mood) are real and your labs show clinically low testosterone on two morning draws. It is the wrong move as a generic "energy" or "vitality" drug for men whose total T is 500+ ng/dL.
Modern TRT protocols are weekly injections of testosterone cypionate at 100-200 mg, dosed and titrated to keep total T in the upper third of the reference range (700-900 ng/dL) without elevating estradiol or hematocrit out of band. The TRAVERSE trial (NEJM 2023) settled the long-running cardiovascular safety question favorably.
The trade you make on TRT: fertility goes down (often to zero) while you're on it. If fertility matters, enclomiphene raises your endogenous testosterone without suppressing it — a different, lighter-touch tool.
What this guide covers
What TRT is, and isn't
Testosterone replacement therapy is the supplementation of exogenous testosterone in men with clinically low endogenous production. It is a treatment for hypogonadism — confirmed low testosterone with symptoms. It is not a generic enhancement protocol for men with normal hormone levels.
Two distinctions matter:
- Primary hypogonadism — the testes themselves can't make enough testosterone. Common causes: injury, mumps orchitis, Klinefelter syndrome, chemotherapy.
- Secondary hypogonadism — the pituitary or hypothalamus isn't signaling the testes correctly. Common causes: obesity, sleep apnea, chronic illness, opioid use, exogenous steroid history. This is the much larger group in modern Western men.
The secondary version is reversible. Weight loss, treating sleep apnea, and getting off opioids can restore endogenous testosterone in a meaningful fraction of men. TRT is the right answer when those upstream fixes are either impossible or insufficient. See secondary hypogonadism reversibility.
Who actually needs TRT
The Endocrine Society's diagnostic criteria are clear: low testosterone on at least two morning draws (total T below ~300 ng/dL using a standard assay), combined with symptoms (low libido, ED, fatigue, depressed mood, reduced muscle mass, increased adiposity, poor concentration). Both halves required.
What disqualifies TRT as a useful tool:
- A single low reading without confirmatory repeat (T is pulsatile and easily depressed by acute illness, sleep loss, or stress)
- "Low" total T with normal free T (often older men with high SHBG; the bioavailable testosterone is fine)
- Symptoms without lab confirmation
- Untreated significant obesity, untreated sleep apnea, or active opioid dependence — fix these first
- Active or suspected prostate cancer; uncontrolled erythrocytosis; untreated severe heart failure
Related: symptoms of low testosterone · free vs total testosterone · who should not take TRT.
The lab markers that matter
A proper TRT workup is not just a total T. The minimum panel:
| Marker | Why it matters | Target range on TRT |
|---|---|---|
| Total testosterone | The headline number. Pulsatile — draw before 10am. | 700-900 ng/dL trough |
| Free testosterone | The bioavailable fraction. What actually binds receptors. | Top quartile of reference |
| SHBG | Carrier protein. High SHBG masks symptoms; low SHBG inflates total T. | 20-50 nmol/L typical |
| Estradiol (sensitive assay) | Testosterone aromatizes to estradiol. Both too-low and too-high cause symptoms. | 20-40 pg/mL |
| Hematocrit | TRT raises red cell mass. Above ~54% → consider dose reduction or therapeutic phlebotomy. | < 52% |
| PSA | Prostate safety marker. Trend is more important than absolute value. | Stable; consult on rises > 1 ng/mL/yr |
| LH / FSH | Distinguishes primary vs secondary hypogonadism. Will be suppressed on exogenous TRT. | n/a once on TRT |
| Lipid panel + ApoB | TRT can shift lipids. ApoB is the cleaner cardiovascular signal. | ApoB < 80 mg/dL ideal |
Deeper dives: free vs total testosterone · SHBG explainer · estradiol management on TRT · ApoB, the real CV number.
Dose, frequency, route
The modern standard for injectable TRT is testosterone cypionate, 100-200 mg weekly subcutaneous or intramuscular. Older protocols used 200-300 mg every 2-3 weeks; weekly (or twice-weekly) split-dosing produces flatter pharmacokinetics, fewer trough symptoms, and better-controlled estradiol.
OPTML's default starting protocol is 140 mg weekly subq, split as 70 mg twice weekly for the steadiest curve. Adjusted at 6-8 week labs to land in the target range.
Other forms (gels, pellets, oral undecanoate, nasal) have their use cases but are not the modern default:
- Transdermal gel — daily, works, but transfer-to-others risk and absorption variability.
- Pellets — 3-4 month implants; you give up dose adjustment.
- Oral undecanoate — FDA-approved, expensive, twice-daily with food.
- Intranasal — three-times-daily, low compliance.
Related: best time of day for TRT injections · twice-weekly vs weekly TRT · subq vs IM injections.
What to expect, month by month
Weeks 1-4
Energy and sleep improve first, often within 7-10 days. Libido starts climbing within 2-4 weeks. Recovery from training improves noticeably. Weight may go up 2-4 lb from water retention as androgen levels normalize.
Months 2-3
Lab recheck. Dose adjustment. Energy and mood baseline lift. Cognitive clarity returns. Sleep continues to improve.
Months 4-6
Most of the realized benefits. Strength continues to climb. Erectile function fully restored for most patients. Hematocrit and estradiol stable at adjusted dose.
Beyond 6 months
The protocol becomes maintenance. Lab checks shift to twice-yearly. PSA tracked annually. Periodic dose adjustments based on labs and symptoms.
Full timeline articles: first 30 days on TRT · ·.
Side effects, real and overblown
Real but manageable
- Erythrocytosis (high hematocrit). Most common adverse finding. Manage with dose reduction, hydration, or periodic blood donation/phlebotomy.
- Acne (transient, mostly during initial androgen shift).
- Hair shedding / accelerated androgenetic alopecia in genetically predisposed men. Finasteride is the standard mitigation if you want it.
- Estradiol elevation — see next section.
- Fertility suppression — see fertility section.
Watched but not common
- Cardiovascular events. The TRAVERSE trial (NEJM 2023, n=5,246, 33 months) found non-inferiority of TRT vs placebo for major adverse cardiac events in middle-aged-and-older men with hypogonadism and elevated CV risk. Settled the question.
- Prostate effects. TRT does not cause prostate cancer in modern evidence. PSA monitoring is still standard practice.
Overblown
"TRT will give you a heart attack." Pre-2023 this was a real open question; TRAVERSE closed it. "TRT shrinks your testicles" — true in volume (10-20% reduction is typical) but reversible on cessation and clinically irrelevant unless fertility is the goal. "TRT will make you aggressive" — well-controlled TRT correlates with reduced irritability versus untreated hypogonadism.
Deeper reading: real side effects of TRT · does TRT cause hair loss · TRT cardiovascular (TRAVERSE).
Estradiol and aromatase management
Roughly 20% of circulating testosterone in men aromatizes to estradiol. Estradiol is not the enemy — it's protective for bones, libido, mood, and joint health. The goal is range, not floor.
Most TRT patients do not need an aromatase inhibitor (anastrozole). Crashing estradiol with an AI causes a worse symptom profile than mild elevation: joint pain, mood collapse, libido loss, fragile bones.
The exception: a small subset of patients with significant adipose tissue or genetic high-aromatase pattern run estradiol >50 pg/mL with classic high-E2 symptoms (water retention, sensitive nipples, mood lability, libido drop). For those patients, low-dose anastrozole (0.25-0.5 mg once or twice weekly) brings E2 into the 20-40 pg/mL band.
See estradiol management on TRT · anastrozole, when and when not · aromatase deep dive.
TRT and fertility
Exogenous testosterone shuts down the hypothalamic-pituitary-testicular axis. LH and FSH drop, intratesticular testosterone collapses, and spermatogenesis stops. For men trying to conceive, TRT is contraindicated.
Options for the fertility-conscious man:
- Enclomiphene (see next section) — raises endogenous T without suppressing the axis.
- hCG + TRT — adding human chorionic gonadotropin maintains intratesticular testosterone and preserves some spermatogenesis. More complex protocol.
- TRT now, restart later — most men recover endogenous function within 3-12 months of stopping TRT, though not all do. Sperm banking before starting is the prudent move if family-building is anywhere on the horizon.
See fertility on TRT · hCG with TRT · post-TRT recovery.
Enclomiphene as an alternative
Enclomiphene is the trans-isomer of clomiphene. It's a selective estrogen receptor modulator (SERM): it blocks estrogen receptors in the hypothalamus, which the hypothalamus interprets as "low estrogen, make more testosterone." LH and FSH rise; the testes produce more T endogenously.
Practical positioning:
- Best for: men with secondary hypogonadism (the pituitary-driven kind), normal-to-low total T with low LH/FSH, men who want to preserve fertility, men under ~40, men who want a step before injectable TRT.
- Not for: primary hypogonadism (the testes can't respond regardless), men with significantly low T who need substantial boost (enclomiphene typically takes patients from ~350 to ~600 ng/dL — useful but not heroic).
- Dose: 12.5-25 mg daily, oral.
- Cost: $129/mo at OPTML, $110/mo on the 3-month prepay.
Compare and decide: OPTML enclomiphene · enclomiphene vs TRT · enclomiphene for fertility.
Frequently asked questions
How long until I feel different on TRT?
Most men feel a sleep and energy shift within 7-14 days. Libido and mood within 2-4 weeks. Body composition within 8-12 weeks of training alongside it.
Will I have to be on TRT forever?
For primary hypogonadism, yes. For secondary hypogonadism, possibly not — fixing the upstream cause (obesity, sleep apnea, opioid use) can restore endogenous function. About half of secondary-hypogonadism patients can come off TRT successfully after addressing the underlying driver.
Is TRT a steroid?
Testosterone is technically an anabolic steroid by chemistry. "Steroid abuse" usually refers to supra-physiological doses (500-1500 mg/wk) used non-medically by bodybuilders. Medical TRT (100-200 mg/wk) restores normal hormone levels and is not pharmacologically comparable.
Can I drink alcohol on TRT?
Yes, moderately. Chronic heavy drinking suppresses testosterone independent of TRT and worsens body-composition outcomes. See alcohol on TRT.
Should I lift weights on TRT?
Yes. The body composition benefits of TRT are largely realized through resistance training. Without it, much of the upside is left on the table.