Understanding the ACTH Stimulation Test
Learn about the ACTH stimulation test, a diagnostic tool used to assess adrenal gland function. Understand why it’s performed, how it works, what to expect, and how to interpret the results.
Written by Dr. Vasanthasree Nair
Reviewed by Dr. Shaik Abdul Kalam MD (Physician)
Last updated on 25th Aug, 2025
If your doctor has recommended an ACTH Stimulation Test, you might have questions about what it is, why it’s needed, and what to expect. This simple guide will help you understand the test in easy terms, so you can feel more confident and prepared.
What is the ACTH Stimulation Test?
The ACTH Stimulation Test is a medical test that checks how well your adrenal glands are working. These small glands, located above your kidneys, produce important hormones like cortisol, which helps your body manage stress, control blood sugar, and regulate metabolism.
The test measures how your adrenal glands respond to ACTH (Adrenocorticotropic Hormone), a hormone made by the pituitary gland in your brain. If your adrenal glands don’t produce enough cortisol, it could indicate a problem like Addison’s disease (adrenal insufficiency) or issues with your pituitary gland.
Why is This Test Done?
Your doctor may recommend this test if you have symptoms such as:
Extreme tiredness or weakness
Low blood pressure (feeling dizzy when standing up)
Unexplained weight loss
Darkening of the skin (especially in Addison’s disease)
Nausea, vomiting, or stomach pain
Salt cravings
It can also help diagnose:
Adrenal insufficiency (when adrenal glands don’t make enough hormones)
Pituitary gland disorders (since the pituitary controls ACTH production)
Monitoring treatment for people already diagnosed with adrenal problems
Consult Top Specialists
How is the Test Performed?
The test is simple and usually done in a clinic or hospital. Here’s what happens:
1. Baseline Blood Sample: A nurse will take a small blood sample to check your initial cortisol level.
2. ACTH Injection: You’ll receive a synthetic form of ACTH (usually through an injection in your arm).
3. Follow-Up Blood Tests: More blood samples are taken at 30 minutes and 60 minutes after the injection to see how your cortisol levels change.
The whole process takes about 60-90 minutes, and you can usually go home afterwards.
How to Prepare for the Test?
Fasting: You may need to avoid eating or drinking (except water) for a few hours before the test.
Medications: Some medicines (like steroids) can affect results, so tell your doctor about any medications you take.
Comfortable Clothing: Wear loose sleeves for easy blood draws.
Relax: There’s no need to worry; the test is safe and painless except for a small needle prick.
What Do the Results Mean?
Normal Response: If your cortisol levels rise significantly after the ACTH injection, your adrenal glands are working well.
Low Response: If cortisol levels stay low, it may mean adrenal insufficiency (Addison’s disease) or a pituitary problem.
High Response: Rarely, very high cortisol could suggest Cushing’s syndrome (too much cortisol production).
Your doctor will explain your results and discuss next steps if needed.
Tips for Managing Adrenal Disorders
If you’re diagnosed with an adrenal issue, lifestyle changes can help:
Balanced Diet: Eat enough salt (if advised), protein, and healthy fats.
Hydration: Drink plenty of water to maintain blood pressure.
Stress Management: Practice relaxation techniques like deep breathing or yoga.
Regular Check-ups: Follow your doctor’s advice on medications (like hydrocortisone if prescribed).
When to See a Doctor?
If you experience symptoms like severe fatigue, dizziness, or unexplained weight loss, consult a doctor. Early diagnosis helps in better management.
If your doctor has recommended an ACTH Stimulation Test, you can easily schedule it through Apollo 24|7. Their expert team ensures a smooth and hassle-free experience.
Conclusion
The ACTH Stimulation Test is a safe and effective way to check adrenal gland function. If you’re feeling unwell with symptoms like extreme tiredness or dizziness, this test can help find the cause. Always follow your doctor’s advice and take care of your health with a balanced lifestyle.
Consult Top Specialists
Consult Top Specialists
Dr. Sandeep Jain
Endocrinologist
15 Years • MBBS, MD (Medicine). FDE (Fellowship in Diabetic Endocrinology)
Bhopal
Apollo Sage Hospitals, Bhopal
Dr. Rama Mohan M V
Endocrinologist
10 Years • MBBS, MD, DM
Nellore
Apollo Speciality Hospitals, Nellore
(50+ Patients)
Dr. Nilakshi Deka
Endocrinologist
11 Years • MD,DM (Endocrinology)
Guwahati
Apollo Hospitals G S Road, Guwahati
(675+ Patients)
Dr Sumanth R
General Physician
2 Years • MBBS
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
Dr. Anand Ravi
General Physician
2 Years • MBBS
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
