How to Read Your Testosterone Lab Results

You got your blood work back. Now what? Lab reports are full of numbers, abbreviations, and reference ranges that don't mean much without context. Here's what everything means — and what to actually do with it.

The Core Markers: What to Look For

Total Testosterone (ng/dL or nmol/L)

This is the big one — the total amount of testosterone circulating in your blood, bound and unbound combined. Labs typically report this in ng/dL in the U.S.

• Below 300 ng/dL: Clinically low. Meets the lab threshold for hypogonadism (with symptoms).
• 300–400 ng/dL: Low-normal. Many men feel suboptimal here.
• 400–700 ng/dL: Normal range. Where most men land.
• 500–900 ng/dL: Optimal zone for most men.
• Above 1,000 ng/dL: High-normal to elevated.

Caveat: Always test in the morning (7–10 AM). Afternoon testosterone can be 30–50% lower and won't give you an accurate picture.

SHBG — Sex Hormone-Binding Globulin (nmol/L)

SHBG binds tightly to testosterone, rendering it inactive. High SHBG means less free, active testosterone — even if total T looks fine.

• Normal range: 10–57 nmol/L for adult men
• High SHBG (>57 nmol/L): Can cause functional low T even with normal total T. More common in older men, those with liver disease, hyperthyroidism.
• Low SHBG (<10 nmol/L): More free T available. Associated with obesity, metabolic syndrome, type 2 diabetes.

Free Testosterone (pg/mL or pmol/L)

The biologically active fraction — only 1–3% of total T. This is what your cells actually use.

• Normal range: ~9–30 pg/mL for adult men (age-dependent)
• Low free T with normal total T = "functional hypogonadism" — still clinically significant
• If your lab used immunoassay for free T, the result may be inaccurate. Use SHBG + total T to calculate it via the Vermeulen formula instead.

LH — Luteinizing Hormone (mIU/mL)

LH is released by the pituitary gland and signals the testes to produce testosterone. It's the "command signal."

• Normal range: 1.7–8.6 mIU/mL (varies by lab)
• Low LH + low T: Secondary hypogonadism (problem is in the brain/pituitary, not the testes). Can often be treated with medications that stimulate the pituitary.
• High LH + low T: Primary hypogonadism (testes are failing despite strong LH signal). More likely to need TRT directly.

FSH — Follicle-Stimulating Hormone (mIU/mL)

FSH stimulates sperm production in the testes. Useful alongside LH to understand the cause of hypogonadism and assess fertility potential.

• Low FSH + low T: Secondary hypogonadism
• High FSH + low T: Testicular damage / primary failure
• Very high FSH often indicates severely impaired spermatogenesis

Estradiol / Estrogen (E2) (pg/mL)

Yes, men have estrogen — and they need it. Estradiol (the primary form) supports bone density, libido, cardiovascular health, and brain function in men.

• Normal range for men: ~10–40 pg/mL
• High E2 (>40 pg/mL on TRT): Can cause water retention, moodiness, gynecomastia
• Low E2 (<10 pg/mL, often from AI overuse): Joint pain, low libido, poor mood — just as problematic as high E2

Hematocrit / CBC

Hematocrit is the percentage of blood volume that is red blood cells. TRT increases red blood cell production.

• Target on TRT: below 52–54%
• Above 54%: Increased blood viscosity and clotting risk — requires action (dose reduction, phlebotomy)

PSA — Prostate-Specific Antigen (ng/mL)

• Normal: below 4.0 ng/mL for most men; lower for younger men
• Get a baseline before starting TRT
• TRT may cause mild PSA increase — a rise of more than 1.4 ng/mL from baseline in any 12 months warrants urological evaluation

What a Comprehensive Panel Looks Like

Common Lab Report Scenarios

Scenario 1: Total T = 280 ng/dL, LH = 1.2 mIU/mL

Low T and low LH = secondary hypogonadism. The pituitary isn't signaling properly. Could be obesity, pituitary adenoma, or functional suppression. May respond to clomiphene, enclomiphene, or hCG before TRT is needed.

Scenario 2: Total T = 480 ng/dL, SHBG = 72 nmol/L

Normal total T, but high SHBG. Calculate free T — it's likely in the low range despite the normal total. This is "functional hypogonadism" and can still qualify for treatment depending on symptoms.

Scenario 3: Total T = 650 ng/dL, everything else normal, still symptomatic

Testosterone is not the issue. Look elsewhere: thyroid function, cortisol, vitamin D deficiency, sleep apnea, depression, or other hormonal imbalances.

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