Testosterone Replacement Therapy (TRT)

What is testosterone replacement therapy?

TRT restores testosterone to a normal range in men who are genuinely deficient. Done properly it can improve sexual function, libido, mood and body composition. Done carelessly it can raise your hematocrit to dangerous levels, permanently affect your fertility, and treat a problem you never had.

The difference between those two outcomes is diagnosis and monitoring — which is what this page is mostly about.

How testosterone deficiency is actually diagnosed

A single low reading is not a diagnosis, and this is where most of what is sold online goes wrong.

Testosterone fluctuates through the day and from week to week. The standard is symptoms plus consistently low levels, measured properly and confirmed on a second occasion. The Endocrine Society asks for at least two early-morning fasting tests, around a common clinical threshold near 300 ng/dL — the same figure the American Urological Association uses. We follow that: two morning draws before anyone starts treatment.

The AUA has noted that up to a quarter of men prescribed testosterone never had it tested first, and nearly half never have it checked again afterward. That is the market you are shopping in.

The test itself is part of the problem

This rarely gets mentioned and it should. Testosterone assays are not standardised across laboratories, and the Endocrine Society is blunt about the consequence: the same blood sample can read low at one lab and normal at another, which drives both over-diagnosis and under-diagnosis.

The CDC runs a certification programme for testosterone assays that harmonises results between labs. Where your level sits near a decision threshold, which assay was used is not a technicality — it is the difference between being offered lifelong therapy and being told you do not need it.

Why is it low? That question comes first

Symptoms alone do not make the diagnosis. Low energy, low libido and low mood are common in aging men and have many causes, and the Endocrine Society is explicit that reversible contributors should be ruled out before anyone reaches for a prescription.

We start with luteinizing hormone — the pituitary signal telling the testes to make testosterone. It separates a problem in the testes from one higher up, and it is the branch point for everything that follows. Sleep apnea, thyroid disease, corticosteroids, opioids and pituitary problems all belong on that list.

So does weight. For men whose testosterone is low in the context of being overweight or obese with no other cause identified, the Endocrine Society's position is that weight loss is typically the first-line treatment — not testosterone. We would rather tell you that and treat the cause than start you on something you may not need.

How is testosterone given?

We offer two routes, and the right one depends on your preference, your schedule and how your levels respond.

Injection. The most common route and the most predictable. Levels are reliable and it is the least expensive option, but it means a regular injection routine.

Topical cream. Applied daily. It avoids injections and produces steadier day-to-day levels, but absorption varies between individuals and there is a transfer risk — the medication can pass to a partner or child through skin contact, so application site and timing matter.

We do not currently offer pellets. If that changes, this page will say so.

What TRT does — and what it does not

The AUA guideline is direct about this, and we would rather quote it than oversell.

Patients should be told that testosterone therapy may improve erectile function, low sex drive, anemia, bone mineral density, lean body mass and depressive symptoms. Patients should also be told that the evidence is inconclusive on whether it improves cognitive function, measures of diabetes, energy, fatigue, lipid profiles and general quality of life.

That second list is exactly what most TRT marketing promises. If you have been told testosterone will fix your focus, your motivation and your metabolism, you have been told something the evidence does not support.

What TRAVERSE actually found — the good and the rest of it

The cardiac question dominated this field for a decade. TRAVERSE, a randomized safety trial in more than 5,200 men, found no meaningful increase in heart attack or stroke over one to four years of treatment. That is genuinely reassuring and it is the finding everyone quotes.

The same trial found two other things, and they are quoted far less often. Treated men had roughly a 50% relative increase in pulmonary embolism, and a higher incidence of bone fractures. The Endocrine Society flags both, and also notes that long-term safety — including for prostate cancer, which develops slowly enough that these trials may simply not have run long enough — remains unestablished.

We are telling you this because a clinic that only quotes the cardiac result is giving you half a trial. It does not mean you should not take testosterone. It means the conversation includes clot risk and bone health, and that you tell us promptly about leg swelling, chest pain or breathlessness rather than waiting for your next appointment.

The 2026 labeling changes, accurately described

In June 2026 the FDA requested changes to testosterone product labeling. These are proposed updates rather than a finished rewrite, and what they cover is narrower than the way it has been reported.

The agency asked to remove the 2015 limitation of use — the statement that safety and effectiveness had not been established in men with low testosterone and no identified cause — citing TRAVERSE. It asked that the prostate cancer contraindication be narrowed to men with metastatic disease. And it asked that the warning about worsening benign prostatic hyperplasia be revised, since trial data have not shown worsening in mild to moderate disease, while recommending continued monitoring where symptoms are severe.

The proposed labeling still recommends assessing risk, screening before treatment and monitoring during it. Nothing in it removes the need for the bloodwork described further down this page.

Fertility — read this before you start

Testosterone therapy suppresses your body's own production of testosterone, and with it, sperm production. In some men that does not fully recover.

The AUA recommends a reproductive health evaluation before treatment for any man interested in fertility, and advises against exogenous testosterone entirely in men currently trying to conceive.

If having children is something you might want — now or later — say so at the first visit. It changes what we recommend and how we approach treatment, and that conversation is only useful before you start rather than after.

What we monitor, and why hematocrit matters most

Erythrocytosis — the blood thickening as red cell concentration rises — is the most frequent dose-dependent side effect of testosterone therapy. Left unwatched it raises the risk of clotting. It is also entirely manageable when someone is actually checking, by adjusting the dose or, occasionally, by therapeutic phlebotomy.

We check hemoglobin and hematocrit, total testosterone, PSA in men over 40, and blood pressure. Estradiol is checked where there are breast symptoms. Bloodwork is done at baseline, again a few months after starting or after any dose change, and at least annually once you are stable.

This is the part that distinguishes medical care from a supply arrangement. A service that ships you vials and checks in by text is not monitoring you, and hematocrit is precisely the thing that hurts men when nobody is looking at it.

Who should not have TRT

Testosterone therapy is not appropriate, or needs sequencing differently, in men with prostate or breast cancer, a prostate nodule or an unexplained raised PSA, an elevated hematocrit, untreated severe sleep apnea, uncontrolled heart failure, a recent heart attack or stroke, a clotting disorder or previous clot, or plans to conceive in the near term.

Some of those are absolute and some are a matter of order — treating the sleep apnea first, for instance. That is a conversation, not a form.

What to expect

The first visit is an assessment: symptoms, history, examination and bloodwork. If your levels come back low we repeat them on a second morning before starting anything.

If treatment is appropriate, we start conservatively and recheck. Sexual symptoms and mood tend to respond within weeks; changes in body composition take months. Therapy is ongoing rather than a course with an end date, and stopping means returning to where you started — which is worth understanding at the outset.

Further reading

• A fuller guide to testosterone therapy — diagnosis, evidence and monitoring
• Sexual health after 50 — where testosterone fits, and where it doesn't

Why choose PhillyMedClub for testosterone replacement therapy in Philadelphia?

Dr. Raneiro diagnoses before he treats. A single low reading is not a diagnosis, so we require symptoms plus two low early-morning fasting measurements on separate days, and we ask why your level is low before reaching for a prescription — where low testosterone sits alongside excess weight with no other cause found, the Endocrine Society's position is that weight loss is first-line, not testosterone, and we would rather treat the cause. We offer injection or topical cream and we do not offer pellets. Monitoring is hematocrit above all, plus testosterone, PSA over 40 and blood pressure. If you might want children, that conversation happens before you start, not after. Assessment and bloodwork precede any treatment, in Fishtown, Philadelphia.