Hormone Blood Tests: The Complete Guide
Hormones control nearly every function in your body \u2014 from energy and mood to fertility and metabolism. This guide covers the key hormone blood tests for men and women, when to get tested, and what your results mean.
Why Hormone Testing Matters
Hormones are chemical messengers that regulate virtually every process in your body. Even small imbalances can cause significant symptoms \u2014 yet many hormone disorders go undiagnosed for years because their symptoms overlap with common complaints like tiredness, weight gain, and low mood.
Unlike standard blood tests such as a full blood count or lipid panel, hormone tests are highly sensitive to timing. The time of day, day of the menstrual cycle, fasting state, and even stress levels can dramatically affect results. Understanding when and how to test is just as important as understanding the results themselves.
In Australia, most basic hormone tests (TSH, fasting glucose, HbA1c) are bulk-billed through Medicare when requested by your GP with a clinical indication. More specialised panels (AMH, DHEA-S, IGF-1) may incur out-of-pocket costs at some pathology providers.
Hormone Panels Explained
Each panel below covers a major hormonal system. We explain what is tested, why it matters, what symptoms to watch for, and when to schedule your blood draw for the most accurate results.
Thyroid Panel (TSH, Free T4, Free T3)
Why It Matters
Your thyroid gland controls your metabolic rate, energy production, body temperature, and weight regulation. TSH is the first-line screening test — it rises when the thyroid is underactive and drops when overactive. Free T4 and Free T3 measure the actual circulating thyroid hormones, and antibodies detect autoimmune thyroid disease (Hashimoto’s or Graves’). In Australia, thyroid disease affects about 1 in 20 people, and women are 5 to 8 times more likely to be diagnosed than men.
Symptoms to Watch For
Unexplained fatigue, weight gain or difficulty losing weight, feeling cold all the time, hair loss or thinning, dry skin, constipation, brain fog, depression, or conversely — anxiety, rapid heartbeat, unexplained weight loss, tremor, and heat intolerance if the thyroid is overactive.
When to Test (Timing Matters)
Thyroid hormones are relatively stable throughout the day, so timing is less critical than for other hormones. However, TSH has a mild diurnal rhythm and peaks in the early morning (around 4–8am), so an early morning fasting blood draw gives the most consistent results. If you are monitoring thyroid medication (levothyroxine), take your blood test BEFORE your morning dose.
Sex Hormones — Women (Estradiol, Progesterone, LH, FSH)
Why It Matters
Female sex hormones regulate the menstrual cycle, fertility, bone density, mood, and cardiovascular health. Estradiol is the primary oestrogen and fluctuates significantly across the menstrual cycle. FSH and LH from the pituitary gland orchestrate ovulation. AMH is a marker of ovarian reserve that does not fluctuate with the cycle and is used in fertility planning. These hormones are also essential for diagnosing PCOS, premature ovarian insufficiency, and confirming perimenopause or menopause.
Symptoms to Watch For
Irregular or absent periods, heavy or painful periods, difficulty conceiving, hot flushes and night sweats, mood swings, vaginal dryness, low libido, acne or excess facial hair (suggesting androgen excess), and bone density loss in post-menopausal women.
When to Test (Timing Matters)
Timing is CRITICAL for female sex hormones. FSH, LH, and estradiol should ideally be tested on Day 2–5 of the menstrual cycle (early follicular phase) for baseline assessment. Progesterone is tested on Day 21 (or 7 days after ovulation) to confirm ovulation occurred. AMH can be tested at any point in the cycle. If periods are irregular or absent, your doctor may test on any day.
Sex Hormones — Men (Testosterone, SHBG)
Why It Matters
Testosterone is the primary male sex hormone, essential for muscle mass, bone density, red blood cell production, libido, mood, and cognitive function. SHBG (Sex Hormone Binding Globulin) determines how much testosterone is biologically available — you can have a normal total testosterone but functionally low free testosterone if SHBG is elevated. LH and FSH help determine whether low testosterone originates from the testes (primary) or the pituitary gland (secondary). Testosterone declines approximately 1–2% per year after age 30.
Symptoms to Watch For
Fatigue and low energy, reduced libido, erectile dysfunction, difficulty building or maintaining muscle mass, increased body fat (especially abdominal), mood changes including irritability or depression, poor concentration, reduced bone density, and decreased body and facial hair growth.
When to Test (Timing Matters)
Testosterone MUST be tested between 7–10am, when levels are at their daily peak. Afternoon samples can be 20–30% lower, which may produce a false diagnosis of low testosterone. A fasting sample is preferred as eating can temporarily lower testosterone. If the first result is low, guidelines recommend repeating the test on a separate morning before starting any treatment.
Adrenal Hormones (Cortisol, DHEA-S)
Why It Matters
Cortisol is your primary stress hormone, produced by the adrenal glands. It regulates blood sugar, blood pressure, immune function, and the sleep-wake cycle. Chronically elevated cortisol (as in Cushing’s syndrome) causes weight gain, high blood sugar, muscle wasting, and thin skin. Chronically low cortisol (adrenal insufficiency or Addison’s disease) causes fatigue, low blood pressure, and salt cravings. DHEA-S is the most abundant steroid hormone and serves as a precursor to both testosterone and oestrogen. It peaks in your 20s and declines steadily with age.
Symptoms to Watch For
Persistent fatigue not relieved by sleep, difficulty handling stress, dizziness on standing, salt or sugar cravings, unexplained weight gain (especially around the face and abdomen), easy bruising, muscle weakness, darkening of skin creases (low cortisol), or high blood pressure with round face and purple stretch marks (high cortisol).
When to Test (Timing Matters)
Cortisol has a strong diurnal rhythm — it peaks within 30–60 minutes of waking (the cortisol awakening response) and is lowest around midnight. Blood cortisol MUST be tested between 8–9am for meaningful results. DHEA-S is more stable throughout the day and can be tested at any time. If Cushing’s syndrome is suspected, your doctor may also order a 24-hour urinary free cortisol or late-night salivary cortisol.
Insulin & Glucose Metabolism
Why It Matters
Insulin is the hormone that controls blood sugar, and insulin resistance is the underlying driver of type 2 diabetes, PCOS, metabolic syndrome, and non-alcoholic fatty liver disease. While most GPs test fasting glucose and HbA1c, a fasting insulin level is far more sensitive — it can detect insulin resistance 5–10 years before glucose levels become abnormal. The HOMA-IR score (calculated from fasting glucose and insulin) quantifies insulin resistance. In Australia, approximately 1.3 million people have type 2 diabetes, and another 2 million have pre-diabetes, many undiagnosed.
Symptoms to Watch For
Sugar and carbohydrate cravings, energy crashes after meals, difficulty losing weight despite effort, increased thirst and urination (late sign), dark patches on skin folds (acanthosis nigricans), fatigue after eating, brain fog, and for women — irregular periods which may indicate PCOS-related insulin resistance.
When to Test (Timing Matters)
Fasting insulin and glucose require a 10–12 hour overnight fast — water is permitted but no food, juice, or milk. The test should be done in the morning. HbA1c does not require fasting as it reflects the average blood sugar over the past 2–3 months. If your doctor suspects reactive hypoglycaemia, a 2-hour oral glucose tolerance test (OGTT) with insulin levels at each time point provides the most detailed picture.
Prolactin
Why It Matters
Prolactin is produced by the pituitary gland and is best known for stimulating breast milk production, but it has wide-ranging effects in both sexes. Elevated prolactin (hyperprolactinaemia) suppresses GnRH, which in turn lowers FSH, LH, testosterone, and oestrogen. This makes prolactin a common but underdiagnosed cause of low testosterone in men, irregular periods in women, and infertility in both. Markedly elevated prolactin (above 200 µg/L) may indicate a pituitary adenoma (prolactinoma), which is usually benign and treatable with medication.
Symptoms to Watch For
In women: irregular or absent periods, milky nipple discharge (galactorrhoea), headaches, and difficulty conceiving. In men: low libido, erectile dysfunction, breast tissue enlargement (gynaecomastia), and sometimes visual field disturbances if a large pituitary tumour is pressing on the optic chiasm. Both sexes may experience headaches and reduced bone density.
When to Test (Timing Matters)
Prolactin is sensitive to stress, exercise, and sleep. Blood should be drawn in the morning, at least 2 hours after waking, and ideally after sitting quietly for 15–20 minutes. Avoid vigorous exercise, breast stimulation, or stressful events before testing. Many medications elevate prolactin including antipsychotics, metoclopramide, and some antidepressants — inform your doctor of all medications.
Vitamin D (a Hormone, Not Just a Vitamin)
Why It Matters
Despite its name, vitamin D functions as a steroid hormone with receptors in virtually every tissue in the body. It regulates calcium absorption, bone metabolism, immune function, mood, and muscle strength. In Australia, despite abundant sunshine, 23% of adults are vitamin D deficient (below 50 nmol/L) and rates are higher in southern states during winter, in dark-skinned individuals, and in people who cover their skin. Deficiency is strongly linked to osteoporosis, muscle weakness, increased infection risk, depression, and emerging evidence connects it to autoimmune disease and cardiovascular risk.
Symptoms to Watch For
Bone pain and muscle aches (especially in the thighs and hips), frequent infections, fatigue and low mood (particularly in winter), slow wound healing, muscle weakness and difficulty standing from a sitting position, and in severe deficiency — bone softening (osteomalacia in adults, rickets in children).
When to Test (Timing Matters)
Vitamin D can be tested at any time of day and does not require fasting. However, seasonal timing matters significantly in Australia — levels are lowest at the end of winter (August–September) and highest in late summer (February–March). Testing in late winter provides the most clinically useful result as it shows your trough level. Medicare bulk bills vitamin D testing only when there is a clinical indication (e.g., osteoporosis, malabsorption, dark skin, limited sun exposure).
Growth Hormone & IGF-1
Why It Matters
Growth hormone (GH) is released in pulses from the pituitary gland, primarily during deep sleep and exercise. Because of this pulsatile secretion, a random GH blood level is almost useless — instead, IGF-1 (produced by the liver in response to GH) provides a stable marker of overall GH activity. IGF-1 is essential for growth in children and for maintaining muscle mass, bone density, body composition, and cellular repair in adults. Growth hormone deficiency in adults causes increased body fat, reduced muscle mass, fatigue, and poor quality of life. Excess GH causes acromegaly.
Symptoms to Watch For
In adults with GH deficiency: increased abdominal fat despite exercise, reduced muscle mass and strength, low energy, poor sleep quality, reduced bone density, and impaired psychological wellbeing. In GH excess (acromegaly): enlarged hands and feet, coarsened facial features, joint pain, excessive sweating, and thickened skin. These symptoms develop gradually over years.
When to Test (Timing Matters)
IGF-1 can be tested at any time of day and does not require fasting, though a morning fasting sample is preferred for consistency. A single random GH level is not useful due to pulsatile secretion. If GH deficiency is suspected, your endocrinologist will arrange a formal stimulation test (insulin tolerance test or glucagon stimulation test) in a supervised hospital setting. IGF-1 levels decline naturally with age, so results must be interpreted against age-adjusted reference ranges.
Symptom-to-Test Quick Reference
Not sure which hormone tests to ask for? Use this table to match your symptoms to the blood tests you should discuss with your GP.
| Symptom | Tests to Request | Possible Cause |
|---|---|---|
| Persistent fatigue | Thyroid panel, cortisol, iron studies, vitamin D, testosterone/estradiol | Hypothyroidism, adrenal insufficiency, iron deficiency, vitamin D deficiency |
| Unexplained weight gain | TSH, fasting insulin, HbA1c, cortisol, testosterone | Hypothyroidism, insulin resistance, Cushing’s syndrome, low testosterone |
| Difficulty losing weight | TSH, Free T3, fasting insulin, HOMA-IR, cortisol | Subclinical hypothyroidism, insulin resistance, elevated cortisol |
| Irregular or absent periods | FSH, LH, estradiol, progesterone, prolactin, TSH, testosterone, DHEA-S | PCOS, premature ovarian insufficiency, hyperprolactinaemia, thyroid disease |
| Low libido (men) | Total and free testosterone, SHBG, prolactin, TSH, estradiol | Low testosterone, elevated prolactin, thyroid dysfunction |
| Low libido (women) | Estradiol, testosterone, DHEA-S, TSH, prolactin | Low oestrogen/testosterone, thyroid dysfunction, elevated prolactin |
| Hair loss or thinning | TSH, iron/ferritin, testosterone, DHEA-S, vitamin D, zinc | Thyroid disease, iron deficiency, androgen excess (women), nutritional deficiency |
| Anxiety and heart palpitations | TSH, Free T4, Free T3, cortisol, calcium, magnesium | Hyperthyroidism, elevated cortisol, electrolyte imbalance |
| Mood changes and depression | TSH, vitamin D, testosterone/estradiol, cortisol, B12 | Hypothyroidism, vitamin D deficiency, hormonal imbalance |
| Difficulty conceiving | FSH, LH, estradiol, progesterone, AMH (women); testosterone, FSH, LH, prolactin (men) | Anovulation, low ovarian reserve, low sperm count, hormonal imbalance |
Medicare Coverage in Australia
Most hormone blood tests are bulk-billed through Medicare when requested by your GP with a valid clinical reason. TSH, fasting glucose, HbA1c, testosterone, estradiol, FSH, LH, prolactin, and cortisol are generally covered. AMH, DHEA-S, and IGF-1 may attract an out-of-pocket fee of $30\u2013$80 depending on the pathology provider. Private pathology labs like Laverty, QML, and Sonic Healthcare publish their fee schedules online. Ask your GP to include a clinical indication on the pathology request to maximise bulk billing eligibility.
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SmarterBlood provides health information and AI-powered blood test analysis. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health or before starting any treatment.