ACTH Stimulation Test (Cortisol, 3 Specimens)
A dynamic test of how well the adrenal glands respond when stimulated, the key check for adrenal insufficiency.
Consider this test if:
- Persistent fatigue, weakness, low blood pressure, nausea, or salt craving suggesting adrenal insufficiency
- Unexplained weight loss with darkening of the skin, raising concern for Addison's disease
- Evaluating adrenal recovery after prolonged corticosteroid use
- A low or borderline morning cortisol that needs a definitive stimulated response to interpret
- 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
This is a procedure, not a single draw: a baseline cortisol is taken, synthetic ACTH is injected, and cortisol is measured again at set intervals. Morning testing is standard because cortisol follows a daily rhythm. Tell the clinician about any steroid medications, including inhaled, topical, or oral forms, since they affect cortisol and may need to be timed or paused. Biotin supplements can interfere with immunoassay results and are usually stopped beforehand.
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What this test is for
The ACTH stimulation test measures cortisol before and after an injection of synthetic ACTH (corticotropin), the pituitary hormone that tells the adrenal glands to make cortisol. Healthy adrenal glands respond by raising cortisol substantially; a blunted or absent rise points to adrenal insufficiency, including Addison's disease and secondary insufficiency from pituitary problems or long-term steroid use. This three-specimen version draws a baseline and two timed post-injection samples to map the cortisol response curve, which is more informative than a single random cortisol when symptoms like persistent fatigue, weakness, low blood pressure, weight loss, nausea, or salt craving raise the question.
A single baseline cortisol can look normal even when the adrenal reserve is impaired, which is why the stimulated response is the deciding measurement. If you are choosing between formats, the two-specimen and three-specimen versions differ only in how many post-injection points are captured; the three-specimen test gives a fuller curve.
Biomarkers tested
Includes 4 biomarkers
- Specimen
- Serum or plasma
- Measures
- Mass concentration
- Specimen
- Serum or plasma
- Measures
- Mass concentration
- Specimen
- Serum or plasma
- Measures
- Mass concentration
- Specimen
- Serum or plasma
- Measures
- Date/time
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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Continuous tracking, all in one place
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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