The 14 markers.
Why every one matters.

The primary male sex hormone and TRT's main target. Total T measures all testosterone in your blood — bound and unbound. It tells you whether your dose is delivering, and tracks how that delivery changes over time. Most clinics target 700–1,100 ng/dL on TRT, but the right number depends on your individual response.

Only 2–3% of testosterone is "free" — unbound and biologically active. The rest is bound to SHBG and albumin and unavailable for cellular use. You can have strong Total T and still feel terrible if SHBG is high and Free T is low. This is why two people on the same dose can feel completely different.

The primary estrogen in men, made when testosterone converts via the aromatase enzyme. TRT raises E2 — some elevation is healthy and necessary. Too high causes water retention, mood instability, and low libido. Too low (often from overusing aromatase inhibitors) causes joint pain, brain fog, and equally poor libido. Balance, not elimination, is the goal.

A protein that binds testosterone and estradiol, making them unavailable. High SHBG means less free testosterone from the same dose — often requiring higher doses or more frequent injections. Low SHBG means faster clearance. SHBG is one of the biggest drivers of why TRT protocols are individual, and it shifts over time.

The percentage of your blood volume made up of red blood cells. Testosterone stimulates red blood cell production — beneficial in small amounts, dangerous when it climbs too high. Elevated hematocrit thickens the blood, raising clot and cardiovascular risk. Most TRT physicians target below 52–54% and will adjust or pause therapy above that threshold.

The oxygen-carrying protein inside red blood cells. Rises in parallel with hematocrit on TRT. Tracking both together provides a complete picture of blood thickening risk. Hemoglobin is a more sensitive early signal — it often rises before hematocrit crosses the clinical threshold, giving more lead time to adjust.

The primary driver of arterial plaque. TRT, particularly at higher doses, can raise LDL in some individuals. Tracking over time catches a trend early — a single high reading is less concerning than a consistent upward trajectory across tests.

Injectable testosterone has a known tendency to lower HDL. A declining HDL trend is a meaningful cardiovascular signal — one of the clearest longitudinal markers that TRT may be creating cardiovascular stress. Easy to miss on a single test; obvious over a year of monitoring.

The sum of all cholesterol fractions. Most useful as context for LDL and HDL — a high total driven by high HDL is very different from one driven by high LDL. Part of the complete lipid picture that TRT shifts over time.

Blood fats that reflect dietary intake and metabolic health. Often elevated in hypogonadal men before TRT and can improve with body composition changes. TRT's effect on triglycerides varies — tracking shows whether your protocol is improving or worsening metabolic health over time.

Covers liver enzymes (ALT, AST), kidney markers (creatinine, BUN, eGFR), electrolytes, and blood glucose. Injectable testosterone at physiologic doses is far gentler on the liver than oral androgens — but liver enzymes can still shift, and long-term TRT users need kidney function tracked. Most clinics recheck CMP every 3–6 months early in therapy, then annually once stable. It's as much about liability and standard of care as biology.

A prostate health marker and early indicator of prostate issues. TRT doesn't cause prostate cancer, but it can accelerate existing disease. Baseline PSA establishes your starting point; periodic monitoring watches for unexpected rises that warrant further evaluation. Not necessarily checked every single panel — typically baseline, at 6–12 months, then annually or as symptoms dictate. Essential for any man over 40 on TRT.

The pituitary signal that tells your testes to produce testosterone. Before TRT, LH levels distinguish primary hypogonadism (testicular failure) from secondary (pituitary origin) — a distinction that affects treatment options. Once TRT starts, exogenous testosterone suppresses LH to near-zero. Running it quarterly adds no actionable information.

Drives sperm production in the testes. Critical for understanding fertility status before starting TRT — exogenous testosterone significantly suppresses FSH and sperm production, often to zero. Like LH, FSH is suppressed by TRT and provides no meaningful monitoring data once therapy is established. Baseline FSH is part of the complete pre-TRT picture for clinical records and fertility counseling.

Controls thyroid output, which affects metabolism, energy, and mood. Undiagnosed hypothyroidism is common and makes TRT feel ineffective — you can optimize testosterone and still feel exhausted if your thyroid is underperforming. TRT doesn't directly change TSH, so routine quarterly testing isn't standard practice. However, clinics may recheck if fatigue persists, symptoms change, or optimization efforts stall without a clear hormonal explanation.

A pituitary hormone that, when elevated, suppresses testosterone and libido. Elevated prolactin (hyperprolactinemia) is an under-screened cause of low T — often caused by a benign pituitary adenoma (prolactinoma) or certain medications. Not part of every intake panel, but important when TRT isn't working as expected, libido remains poor despite good hormone numbers, or symptoms suggest pituitary involvement.