Cortisol, Free and Total
The active, unbound fraction of your main stress hormone alongside the total, useful when binding proteins distort the standard reading.
Consider this test if:
- Investigating symptoms of cortisol excess such as central weight gain, easy bruising, high blood pressure, or muscle weakness
- Investigating possible adrenal insufficiency with fatigue, low blood pressure, weight loss, or salt craving
- Pregnant, on estrogen, or with low albumin, where total cortisol can mislead and the free fraction is more reliable
- Following up an abnormal screening cortisol with a more precise free and total measurement
- HSA/FSA eligible
- Results delivered to your dashboard · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
Cortisol follows a daily rhythm, peaking in the early morning and falling through the day, so collection time matters and most baseline draws are done around 8 a.m. Note any corticosteroid use (oral, topical, inhaled, or injected) since these affect results, and tell the lab if you take estrogen or are pregnant. Acute illness, physical stress, and poor sleep can transiently raise cortisol. Fasting is not required.
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What this test is for
Cortisol is the adrenal hormone that regulates blood sugar, blood pressure, metabolism, inflammation, and the body's response to stress. Most cortisol in the blood is bound to carrier proteins; only the free fraction is biologically active, and this test measures both the free and total levels in serum. Free cortisol is particularly useful when binding proteins are altered, as in pregnancy, estrogen therapy, or low albumin, situations where total cortisol alone can read misleadingly high or low. Elevated levels point toward Cushing's syndrome, while consistently low levels raise the question of adrenal insufficiency (Addison's disease), which can present with fatigue, weakness, low blood pressure, weight loss, and salt craving.
This serum panel reports both fractions at a single point in time. If your question is the daily rhythm specifically, the timed AM and PM serum tests or salivary cortisol address that, and 24-hour urinary free cortisol is the standard measure of total daily output for a Cushing's workup.
Biomarkers tested
Includes 2 biomarkers
Cortisol is the hormone your adrenal glands release to manage stress, blood sugar, blood pressure, and your wake-sleep rhythm, peaking in the morning and tapering through the day. High levels can point to chronic stress, Cushing's syndrome, or overtraining, while low levels suggest adrenal insufficiency (Addison's disease) or a pituitary problem, either of which can drive fatigue, weight changes, poor sleep, low blood pressure, and brain fog. Testing it establishes a baseline for how your body handles stress and helps investigate unexplained exhaustion, mood swings, or a sleep-wake cycle that feels out of sync, especially when paired with ACTH or DHEA-S for fuller context.
- Specimen
- Serum or plasma
- Measures
- Mass concentration
- Specimen
- Serum or plasma
- Measures
- Mass concentration
What to expect
- 1 Book instantly
Click, book, done. Choose a convenient lab location near you. Transparent, up-front pricing.
- 2 Quick lab visit
Testing to fit your busy schedule, usually 15 minutes or less. Walk-in and appointments available.
- 3 Fast, dashboard-delivered results
Your results post straight to your dashboard as soon as the lab completes them.
- 4 Expert guidance
Included with Mito membership. A clinician reviews your results and your personalized action plan follows, with clear next steps.
Everything your health needs,
in one membership
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Every test at our cost
Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
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Upload past labs and watch your trends over time. Every marker and visit lives in one longitudinal record, so all your care stays together.
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Year-round clinician support
Text anytime and get clinician-reviewed answers. When you want to go deeper, 1:1 consultations are available at affordable rates.
All for $9/month
Order any test or consult without joining. For $9/month, members unlock member prices, trend tracking, and year-round clinician guidance.
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Frequently asked questions
View all FAQsHow does pricing work?
Every test shows the member price next to the standard non-member price, so you can see what membership saves you. The member price is our cost — covering the lab and what it takes to run the service — never a profit on the test itself; Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9/mo, and you still pay the lab’s order fee. Prices are itemized before you pay, with no hidden fees.
Where do I get tested?
Choose a partner lab (Quest, Labcorp, or BioReference) at checkout. If your cart spans multiple tests, we consolidate the whole order onto a single lab so you only make one visit.
Is this eligible for HSA/FSA?
Yes. This test is HSA/FSA eligible, and you can pay with your HSA/FSA card at checkout.
When will I get my results?
Your results post to your dashboard once your lab completes them, then a clinician reviews them and your full analysis and personalized action plan (with clear next steps) follow. Turnaround varies by test: specialty assays and at-home kits take longer, and each test shows its expected turnaround before you buy.
Do I need a doctor’s order?
No. Mito provides the lab order for you, so you can book and get tested without a separate doctor visit.
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