Getting on testosterone replacement therapy (TRT) requires a confirmed diagnosis of low testosterone through blood work, a symptom evaluation, and a prescription from a qualified doctor. The process typically takes a few weeks from your first appointment to your first dose, though insurance requirements or specialist referrals can stretch that timeline. Here’s what each step looks like.
What Qualifies You for TRT
TRT isn’t prescribed based on symptoms alone. You need both low testosterone levels on blood tests and symptoms consistent with that deficiency. The American Urological Association sets the diagnostic cutoff at a total testosterone level below 300 ng/dL, and your blood must be drawn in the early morning (typically before 10 a.m.) when testosterone peaks. You’ll need at least two low readings on separate days to confirm the diagnosis. Most insurance companies, including Aetna and similar plans, explicitly require these two confirmed morning draws before they’ll approve coverage.
It’s worth knowing that 300 ng/dL is a general threshold, not a perfect number. For men in their 20s, the middle of the normal range is roughly 409 to 558 ng/dL. For men in their late 30s and early 40s, it drops to around 350 to 478 ng/dL. So a reading of 310 ng/dL might technically clear the cutoff but still be well below average for your age, which is something you can discuss with your doctor.
Common symptoms that support a diagnosis include low sex drive, erectile difficulties, persistent fatigue, loss of muscle mass, increased body fat, depressed mood, and poor concentration. Your doctor will assess these alongside your lab results.
Which Doctors Prescribe TRT
Your primary care doctor can diagnose low testosterone and prescribe TRT, but many will refer you to a specialist. Urologists and endocrinologists are the two main specialists who manage testosterone therapy. Endocrinologists focus on hormonal disorders broadly, while urologists handle male reproductive health and are especially relevant if fertility is a concern.
Testosterone clinics (sometimes called “men’s health clinics” or “Low T centers”) are another option. These clinics streamline the process and can often get you started faster. However, some experts caution that the doctors staffing these clinics may not always be specialists in urology or endocrinology, and they may be more inclined to prescribe testosterone aggressively. If you go this route, make sure the clinic follows standard diagnostic protocols, including the two-test requirement.
The Blood Work You’ll Need
Beyond the two morning testosterone draws, your doctor will order additional labs before writing a prescription. These serve two purposes: identifying why your testosterone is low and making sure treatment is safe for you.
- LH (luteinizing hormone): This tells your doctor whether the problem originates in your testes or in your brain’s signaling system. Low LH with low testosterone suggests a pituitary or hypothalamic issue, which may require further imaging.
- Prolactin: Measured when LH is low or borderline, since elevated prolactin can signal a pituitary tumor that needs its own treatment.
- Hematocrit and hemoglobin: These measure your red blood cell concentration. TRT raises red blood cell production, so your doctor needs a baseline to monitor for dangerous thickening of the blood later.
- PSA (prostate-specific antigen): Required for men over 40 to rule out prostate cancer before starting therapy.
If you’re interested in having children, you should mention this upfront. TRT suppresses sperm production, sometimes severely. Your doctor will want to do a fertility evaluation and may recommend alternative treatments that boost your body’s own testosterone production without shutting down sperm.
Conditions That May Disqualify You
TRT is contraindicated if you have untreated prostate cancer or breast cancer. Men considered high-risk for prostate cancer, including those with a first-degree relative who had it or African-American men with a PSA above 3 ng/mL, face additional scrutiny before approval. Obstructive sleep apnea is a relative contraindication, meaning TRT can worsen it, so your doctor will want that condition treated or well managed first. Severely elevated red blood cell counts at baseline may also delay treatment.
Choosing a Delivery Method
Once you’re approved, you and your doctor will pick a delivery method based on your lifestyle, comfort level, and cost. There are more options than most people realize.
- Injections: The most common and least expensive option. Testosterone cypionate and enanthate are injected every 7 to 14 days, either at a clinic or self-administered at home after brief training. A longer-acting injectable version requires a shot only every 10 weeks but must be given in a medical office.
- Topical gels: Applied daily to the shoulders, upper arms, or abdomen. Convenient but carry a risk of transferring testosterone to partners or children through skin contact. Doses typically range from 50 to 100 mg daily.
- Patches: Worn on the skin and changed daily. Some men find them irritating.
- Pellets: Rice-sized pellets implanted under the skin in a quick office procedure, lasting 3 to 4 months per insertion.
- Nasal gel: Applied inside each nostril three times a day. Less common but avoids skin transfer concerns.
Cost and insurance coverage often drive the decision. Generic injectable testosterone cypionate is typically the cheapest option, sometimes under $30 per month even without insurance. Brand-name gels, patches, and pellets cost significantly more, and insurance coverage varies. Your doctor will aim to dose your therapy so your total testosterone lands in the middle of the normal range.
What to Expect After Starting
TRT doesn’t deliver all its benefits at once. Different symptoms improve on different timelines, so managing expectations matters.
The earliest changes involve sex drive and mood. Improvements in libido typically appear within 3 weeks and plateau around 6 weeks. Mood and energy follow a similar early curve: decreases in fatigue and listlessness show up within 4 to 6 weeks, and improvements in depressive symptoms begin within 3 to 6 weeks, though full benefit may take 18 to 30 weeks. Several psychological improvements, including reduced anxiety and increased concentration and self-confidence, have been noted as early as 3 weeks in.
Body composition changes take longer. Shifts in fat mass, lean muscle, and strength become noticeable around 12 to 16 weeks and stabilize at 6 to 12 months, with marginal gains continuing beyond that. Erectile improvements that go beyond initial libido changes may take up to 6 months to fully develop. Bone density improvements begin around 6 months and continue for at least 3 years.
Ongoing Monitoring and Side Effects
TRT is not a “set it and forget it” treatment. You’ll need regular blood work, especially in the first year. Hematocrit should be checked every 3 to 6 months initially and annually after that. PSA monitoring continues yearly for men over 50, and every 2 to 4 years for younger men with risk factors. TRT tends to raise PSA by about 0.30 ng/mL on average.
The most common side effect is erythrocytosis, an increase in red blood cell mass that thickens your blood and raises the risk of clots. If your hematocrit exceeds 52%, your doctor will likely recommend therapeutic phlebotomy (essentially a blood donation) to bring it down. Some men experience elevated estrogen levels from testosterone converting into estradiol, which can cause breast tenderness or tissue growth. This is typically manageable with medication adjustments.
Blood pressure and cardiovascular markers also warrant attention, particularly in older men or those with existing heart disease. Your doctor may monitor your lipid profile and blood pressure alongside your testosterone labs. Changes in lipids appear within about 4 weeks of starting therapy, with maximum effects at 6 to 12 months.