Adrenal suppression is a condition where your adrenal glands stop producing enough cortisol on their own, usually because long-term steroid medication has signaled your body to shut down its natural production. It’s one of the most common hormonal side effects of glucocorticoid therapy, and it can range from mild fatigue to a life-threatening emergency depending on severity.
How Your Body Normally Makes Cortisol
Your brain and adrenal glands work together in a feedback loop. The hypothalamus (a region deep in the brain) releases a signaling hormone that tells the pituitary gland to produce another hormone called ACTH. ACTH then travels through the bloodstream and tells the adrenal glands, which sit on top of your kidneys, to release cortisol. Cortisol helps regulate blood pressure, blood sugar, metabolism, and your stress response.
When cortisol levels rise high enough, the brain detects this and dials back its signals. This keeps everything in balance. But when you take a steroid medication like prednisone, your body treats it as if you already have plenty of cortisol. Over time, the brain stops sending those signals altogether, and the adrenal glands begin to shrink from disuse. This is adrenal suppression: the natural cortisol-producing system has gone dormant.
What Causes It
The overwhelming majority of cases come from taking glucocorticoid medications, the class of steroids prescribed for inflammation, autoimmune conditions, asthma, and many other problems. Oral steroids like prednisone are the most common culprit, but inhaled steroids (used for asthma and COPD), topical creams, and even joint injections can cause suppression under certain circumstances.
For oral steroids, the Endocrine Society identifies two thresholds that both need to be crossed for meaningful risk: using a dose higher than the body’s natural daily cortisol output (roughly equivalent to 4 to 6 mg of prednisone per day), and using it for longer than three to four weeks. That said, predicting exactly who will develop suppression is difficult. Some people develop it at lower doses or shorter durations, which is why careful monitoring matters regardless of the prescription.
Inhaled corticosteroids carry a lower but real risk. A large population study found that the rate of adrenal insufficiency among inhaled steroid users was about 1.7 per 1,000, compared to 0.5 per 1,000 in non-users. Each 100 microgram per day increase in dose was linked to a 3% rise in risk. People using high-dose inhalers, using them for more than a year, or combining multiple steroid formulations (say, an inhaler plus a nasal spray plus a cream) should be particularly aware.
Intra-articular steroid injections, the kind used for knee or shoulder pain, can suppress adrenal function for up to two months after a single injection. Taking certain medications that slow your liver’s ability to break down steroids (known as CYP3A4 inhibitors, which include some antifungals and HIV medications) also amplifies the risk.
Symptoms to Recognize
The symptoms of adrenal suppression mirror what happens when your body doesn’t have enough cortisol. The most common ones are:
- Chronic fatigue that doesn’t improve with rest
- Muscle weakness
- Loss of appetite and weight loss
- Nausea, vomiting, or abdominal pain
- Low blood pressure, especially dizziness when standing up
- Low blood sugar
- Joint pain
- Irritability or depression
These symptoms often creep in gradually, which makes them easy to dismiss or attribute to something else. Many people first notice them when they’re tapering off steroids or during a physical stress like illness or surgery, when the body would normally ramp up cortisol production but can’t.
When It Becomes an Emergency
Adrenal crisis is the most dangerous form of adrenal suppression. It happens when cortisol levels drop so low that the body can’t maintain basic functions. Triggers include suddenly stopping steroid medication, a serious infection, surgery, or any major physical stress.
Signs of adrenal crisis include severe weakness, confusion or loss of consciousness, high fever, rapid heart rate, very low blood pressure, and intense abdominal or flank pain. This is a medical emergency requiring immediate treatment with injectable hydrocortisone. Many people with known adrenal insufficiency carry an emergency syringe of hydrocortisone that a family member can administer into muscle if they become too weak to take pills.
How It’s Diagnosed
The first step is usually a morning blood cortisol test, drawn between 6 a.m. and 8 a.m. when cortisol naturally peaks. Normal morning cortisol ranges from about 10 to 20 mcg/dL. A very low morning reading (below 2 mcg/dL) strongly suggests the adrenals aren’t functioning properly.
The definitive test is the ACTH stimulation test. You’re given a synthetic version of ACTH, the hormone that normally tells your adrenals to produce cortisol, and your blood cortisol is measured 30 to 60 minutes later. Historically, a response of 18 mcg/dL or higher was considered normal. More recent research using modern, more precise lab assays has proposed lowering that cutoff to around 14 to 15 mcg/dL to reduce false positives, meaning fewer people being incorrectly told their adrenals are failing.
How Steroids Are Safely Stopped
The reason doctors taper steroids rather than stopping them abruptly is to give the adrenal glands time to wake back up. Tapering generally happens in two phases. First, the dose is gradually reduced to a near-physiological level, roughly equivalent to what your body would make on its own (about 5 mg of prednisolone per day). This phase can move relatively quickly depending on why the steroid was prescribed.
The second phase is slower and more delicate. For someone who has been on prednisolone for more than six months, a typical approach is reducing by 1 mg per month from the 5 mg level down to zero. For hydrocortisone, reductions of about 4 mg per month below a 20 mg daily dose follow a similar logic. The pace depends on how long you’ve been on steroids, what dose you were taking, and whether symptoms of insufficiency appear during the taper.
Switching from long-acting steroids like dexamethasone to shorter-acting ones like hydrocortisone or prednisone before tapering is generally recommended, since shorter-acting drugs give the adrenal glands more time each day without steroid exposure, encouraging them to resume production.
How Long Recovery Takes
Recovery of the adrenal system after prolonged steroid use is slow and not guaranteed. One study tracking patients after long-term glucocorticoid exposure found that about 61% had recovered adequate adrenal function within two years. That means roughly 4 in 10 people still had some degree of insufficiency two years after stopping treatment.
During the recovery period, your body is vulnerable to adrenal crisis during illness, injury, or surgery. You may need temporary “stress doses” of hydrocortisone during these times, even if you’ve already stopped taking daily steroids. Wearing a medical alert bracelet is a practical step that ensures emergency responders know about your adrenal status if you can’t communicate.