The Complete Hormone Panel: Every Test Explained

Total Testosterone

The starting point for every male hormone evaluation and a critical (often overlooked) test for women. Total T includes both protein-bound and free testosterone. Best timed for 7-9 AM when levels peak. Two readings spaced 2+ weeks apart are recommended before diagnosing low T (Endocrine Society guidelines, 2018).

Free Testosterone

The biologically active fraction. Calculated free T (using total T, SHBG, and albumin in the Vermeulen equation) is more reliable than direct measurement on most platforms. Critical when SHBG is abnormal, total T can look fine while free T is clearly low.

SHBG (Sex Hormone-Binding Globulin)

The taxi service for testosterone, high SHBG means more T bound up, less free. Elevated SHBG is associated with hyperthyroidism, liver disease, oral estrogen, aging, and high-fiber/low-protein diets. Low SHBG is associated with insulin resistance, obesity, and inflammation. Pattern: low SHBG + low free T = a metabolic problem; high SHBG + low free T = often age- or thyroid-related.

Estradiol (E2), Sensitive Assay

For men, an underrated and critical test. Too-low E2 (<20) causes joint pain, low libido, and bone density loss. Too-high E2 (>40) causes water retention, mood changes, and gynecomastia risk. Always order the sensitive (LC-MS/MS) assay for men, the standard immunoassay is unreliable at low concentrations (Rosner et al., J Clin Endocrinol Metab, 2013).

Progesterone

For cycling women, draw 7 days after ovulation (typically days 19-22 of a 28-day cycle). Low luteal progesterone is associated with irregular cycles, sleep disturbance, anxiety, and infertility. In perimenopause, progesterone declines first, often years before estradiol drops noticeably.

DHEA-Sulfate

The body's most abundant adrenal hormone and the precursor to both testosterone and estrogen. Drops ~80% from age 25 to 75. Low DHEA-S is associated with chronic stress, adrenal insufficiency, and aging. Very high values warrant evaluation for adrenal disease or PCOS.

LH and FSH

The brain's signals to the gonads. The most important pattern in male hormone evaluation:

• Low T + low/normal LH/FSH = secondary hypogonadism (problem at the brain or pituitary level, often treatable with enclomiphene or by addressing root causes like obesity, sleep apnea, opioid use)
• Low T + high LH/FSH = primary hypogonadism (testes can't produce, TRT typically the only option)

For women, FSH rising consistently above 25 mIU/mL signals advancing perimenopause. The day 3 FSH alongside estradiol is the classic perimenopause workup.

Prolactin

Suppresses LH/FSH, libido, and fertility when elevated. High prolactin in men can indicate a pituitary adenoma; mild elevations are common with stress, recent intercourse, or certain medications. Always rule out before pursuing TRT in low-T evaluation.

IGF-1

The downstream marker of growth hormone activity. Low IGF-1 is associated with poor recovery, slow muscle gain, and cognitive decline. High IGF-1 may slightly increase certain cancer risks at the upper extreme. Best target: upper third for age, not above.

TSH

The pituitary's signal to the thyroid. Higher = thyroid is being pushed harder. Most labs flag only above 4.5, but optimal medicine targets <2.0 (Surks et al., JAMA, 2004). TSH alone is insufficient, always run with free T3 and free T4.

Free T4 and Free T3

T4 is the storage form; T3 is the active hormone. Many people have normal TSH and T4 but suboptimal T3 due to poor T4-to-T3 conversion (driven by stress, low calorie intake, low selenium, or inflammation). Symptoms of hypothyroidism with TSH 1.5 and Free T3 of 2.4, common and missed.

Reverse T3

The "off-switch" form of T3. Elevated under stress, illness, low calorie intake, or inflammation. High reverse T3 with low free T3 is the signature of thyroid hormone resistance and explains many "TSH normal but I feel hypothyroid" presentations.

TPO and Thyroglobulin Antibodies

Detects autoimmune thyroid disease (Hashimoto's). Often present years before TSH abnormalities. Strongly worth testing in any unexplained fatigue, weight gain, or perimenopause workup.

Fasting Insulin and HbA1c

Hormonal context. Insulin resistance, driven by visceral fat, directly suppresses testosterone in men and elevates androgens in women (PCOS pattern). Fixing insulin sensitivity often resolves "low T" without needing TRT.

Cortisol (AM)

The stress signal. Chronically elevated cortisol suppresses testosterone, raises blood sugar, and drives visceral fat. Chronically suppressed cortisol indicates HPA axis dysfunction. Most reliable as part of a 4-point salivary cortisol curve, but morning serum is a useful screen.