Cortisol and testosterone: how the two relate and what tests show

Cortisol and testosterone are separate hormones, made mostly in different glands and measured by different blood tests. Reviews link sustained physical or psychological strain and poor sleep with lower testosterone, and cortisol often rises in the same situations. But the two do not always move together, and neither result tells you the other.

Two hormones, two glands

The adrenal glands, two small glands above the kidneys, make cortisol. MedlinePlus says the testicles are the main producers of testosterone in males. In women, a 2022 review in Diagnostics says testosterone production is shared nearly equally between the ovaries and the adrenal glands.

Both hormones are higher in the morning. MedlinePlus says cortisol is normally highest in the morning and much lower around 4 p.m. It says testosterone blood samples are taken in the morning, between 7 and 10, when levels are typically highest.

The curve shows the usual daily pattern for cortisol only. A morning draw suits both hormones, but they are still two tests. For cortisol timing, see AM and PM cortisol.

What the research says about cortisol and testosterone

Sustained strain

A 2026 review in the Journal of Clinical Endocrinology and Metabolism looked at military field studies, endurance athletes and competition. Its authors argue that when testosterone drops during sustained stress, it is commonly a signal from the brain and pituitary turning testicular production down, not failure of the testicles. They point to severe energy deficit, disrupted sleep and uncontrollable psychological stress. They also say sex hormone-binding globulin (SHBG) often rises, which lowers free testosterone further. In the studies they cite, the testicles still responded when stimulated.

The same review notes that cortisol rises in both winners and losers of a competition, and says activation of the stress hormone system and suppression of the testosterone system do not always go together. It is a narrative review of mostly military and athletic groups. It does not describe the average person.

Sleep

A 2022 review in Reviews in Endocrine and Metabolic Disorders says sleep loss and shorter sleep are associated with lower morning, afternoon and 24-hour testosterone. It says they are associated with higher afternoon cortisol, but not higher morning or 24-hour cortisol. It also says obstructive sleep apnea is associated with lower testosterone, even after accounting for age and obesity. See cortisol and sleep.

What this adds up to

These are associations in specific groups. They don’t show that high cortisol lowers testosterone in daily life, and they give no number at which either hormone is “too” high or low. Some websites use a testosterone-to-cortisol ratio. None of the clinical sources we used gives a cut-off for it, so we don’t offer one.

When the link is clearer

Cushing’s syndrome. NIDDK says it occurs when the body makes too much cortisol over a long time. It says men with Cushing’s syndrome may have decreased fertility, lowered interest in sex and erectile dysfunction. The most common cause is long-term, high-dose use of glucocorticoid medicines, such as those used for asthma, rheumatoid arthritis and lupus. If you take one, ask your prescriber about it. Don’t stop or change it yourself. Cushing’s syndrome from the body’s own overproduction is rare, with estimates of about 40 to 70 people per million. Testing is done by a clinician with a late-night saliva test, a 24-hour urine collection or a dexamethasone suppression test, and a single blood cortisol can’t diagnose or rule it out. See high cortisol.

Too little cortisol. NIDDK lists loss of interest in sex among the symptoms of adrenal insufficiency, alongside long-lasting fatigue, muscle weakness, loss of appetite and weight loss. It says the pituitary makes many hormones, so ACTH may not be the only one lacking when the pituitary is the cause. MedlinePlus lists a pituitary gland disorder among the causes of low testosterone in males. A pituitary problem is one place where both can be affected. See low cortisol.

If you have repeated vomiting, severe weakness or fainting, get urgent care instead of ordering a test. See adrenal crisis.

How low testosterone is diagnosed

MedlinePlus says three tests measure testosterone: total testosterone, which is the most common; free testosterone; and bioavailable testosterone. It says a testosterone test alone can’t diagnose any condition, but abnormal results with symptoms may signal a health problem. Symptoms it lists for low testosterone in males include low sex drive, erectile dysfunction, infertility, enlarged breasts, lack of face or body hair, loss of muscle mass, and thinning bones or anemia without a known cause. See cortisol and libido.

MedlinePlus lists several possible causes in males: problems with the testicles, long-lasting liver or kidney disease, a pituitary gland disorder, benign tumors, injury to the testicles, alcohol use disorder and genetic conditions such as Klinefelter syndrome. A 2024 paper in the Journal of the Endocrine Society warns that some “men’s health” clinics diagnose low testosterone from symptoms such as fatigue and low libido without measuring it. It says low testosterone from a cause outside the testicles is far more common than from the testicles themselves, and that causes include opioid use, alcoholism, depression, sleep apnea and pituitary disorders. Those can be more dangerous than the low testosterone they cause, which is why a clinician looks for the cause rather than stopping at the number.

What can change a reading

• Carrier proteins. A review in JBMR Plus says about 44% of testosterone is bound to SHBG and about 50% to albumin, leaving about 2% free. It says estrogens and thyroid hormone raise SHBG, and that obesity, diabetes, inflammation and liver disease can change it. Total testosterone can then mislead. Cortisol has a carrier protein too. Estrogen taken by mouth raises it, so total cortisol can read high, according to the 2023 Diagnostics review. Tell the clinician what you take.
• Biotin. The FDA says biotin, or vitamin B7, is used in hormone tests, is found in multivitamins and in products marketed for hair, skin and nails, and can cause falsely high or falsely low results depending on the test.
• Medicines. MedlinePlus says some medicines may affect testosterone levels. Tell whoever orders the test what you take, and don’t stop any medicine on your own.

Where a cortisol test fits

A cortisol test does not measure testosterone. It fits when a clinician suspects too much or too little cortisol, for example easy bruising and wide purple stretch marks, or long-lasting fatigue with weight loss. A morning blood cortisol can be a first step, but only a first step. For testosterone, ask your clinician which test fits. Prices for the same type of test vary widely between sellers, and it is worth comparing. See the cortisol test guide and cost and where to buy.

Women and testosterone

MedlinePlus says women have testosterone in smaller amounts. In females, the test is mostly used for symptoms of high testosterone, such as extra hair on the body or face, scalp hair loss, voice changes, irregular or no periods, infertility and acne. It lists polycystic ovary syndrome, ovarian problems, an adrenal gland disorder such as congenital adrenal hyperplasia and a pituitary disorder among causes. See cortisol and PCOS.

Quick answers to related questions

Cortisol and DHEA-S

MedlinePlus says DHEAS is a steroid hormone, mostly made in the adrenal glands, and an androgen found in both sexes. It says DHEAS plays an important role in making testosterone and estrogen, and that the test is often done along with testosterone tests in men. Cortisol is another adrenal hormone and is a separate test. See the DHEA-S test.

Estrogen and cortisol

Estrogen taken by mouth raises cortisol’s carrier protein and can push total cortisol up, as above. The 2024 Journal of the Endocrine Society paper puts the rise at about 67 percent in women taking birth control pills, a figure it takes from one earlier study. Free cortisol tests in urine or saliva are not affected. See cortisol and birth control.

Cortisol and insulin

NIDDK lists insulin resistance, prediabetes and type 2 diabetes among the complications of Cushing’s syndrome. For the wider picture, see cortisol and blood sugar.

Cortisol and cholesterol

NIDDK lists unhealthy cholesterol levels among the complications of Cushing’s syndrome. It also says hypothyroidism can contribute to high cholesterol and that anyone with high cholesterol should be tested for it. A cortisol test is not how cholesterol is checked. See cortisol and the thyroid.

When to see a clinician

See a clinician for low sex drive, erectile problems, fertility trouble, or unexplained fatigue or muscle loss that lasts. Mention your sleep, any snoring or breathing pauses at night, alcohol use, and every medicine you take. Don’t change a medicine on the strength of a test result.