Read this before anything else
1. If you are vomiting or have diarrhoea, you cannot absorb your steroid tablet. This is the sentence that matters most on this page, and almost nobody says it. A tablet you throw up does not work. If you cannot keep medication down, you are not covered, and this is an emergency, not a reason to stay home and rest. Clinical guidance is explicit that people who cannot take oral steroids need them by injection. Call for help.
2. If you have an emergency hydrocortisone injection, use it. Do not save it for when things get worse, and do not wait for permission. If you cannot do it yourself, someone with you should. Guidance is that patients at risk should have injectable hydrocortisone available and that family members should be trained to give it. Then call emergency services.
3. Never stop or reduce your steroid on your own. Not because you feel better, not because you feel worse, not because a page on the internet explained the mechanism to you. Abruptly stopping is a recognized cause of adrenal crisis, which is life-threatening. Until your own production restarts, the medication is the only cortisol you have.
Already stopped abruptly? Contact the doctor who prescribed it today. Do not wait and see, and do not restart on a dose you have guessed at. Learn the crisis signs below, and if any of them appear, call emergency services.
An adrenal crisis can look exactly like a stomach bug
This is the trap that kills people. A gastrointestinal or flu-like illness is the most common trigger of a crisis, and a crisis itself causes vomiting, diarrhoea, weakness and abdominal pain. It is very easy to conclude you have a bad bug and go to bed.
Signs of an adrenal crisis:
- Severe weakness, drowsiness, or confusion
- Severe vomiting and diarrhoea, and dehydration. Remember you cannot absorb tablets through this
- Fever
- Low blood sugar, which can progress to seizures or loss of consciousness
- Severe pain in the abdomen, lower back, or legs
- Dizziness, collapse, or loss of consciousness from very low blood pressure
A crisis without a fever is still a crisis. Steroids suppress inflammation and blunt the body's fever response, so you may not run a temperature even when something serious is happening. Never use the absence of fever to reassure yourself. The same blunting means steroids can mask the usual signs of a serious infection: if you feel suddenly worse, or something simply feels different, get seen.
Call emergency services and say: "I take steroids. I may have adrenal insufficiency and may need hydrocortisone." Clinical guidance is explicit that treatment must not wait for test results. Being wrong about a stomach bug costs you an afternoon. Being wrong about a crisis costs more than that.
Four things you should have, not four things to ask about
These are standard safety measures for anyone whose adrenal function is suppressed. If you do not have them, that is a gap to close, and it is reasonable to raise it now rather than waiting.
- A steroid emergency card. The NHS issued a national patient safety alert making these standard after deaths from unrecognized adrenal crisis. It is not an optional extra.
- Medical alert identification, so that if you cannot speak for yourself, whoever is treating you knows within seconds.
- An emergency hydrocortisone injection kit, and someone at home who knows how to use it.
- Sick-day rules. Illness, infection, surgery and injury all increase the cortisol your body needs, which is the opposite of most people's instinct while tapering. You need a written plan for what to do when you are ill. If you are ill right now and have no plan, contact your doctor today. Do not wait for a routine appointment.
And this does not end when the tablets do. Your adrenal glands can stay suppressed for many months after your last dose. The crisis risk in this box applies to you for as long as that lasts, not just while you are still tapering.
If you take steroids by any route, this page is about you
This page says "prednisone" because that is what people search for, but the axis can be suppressed by any route of administration. That includes inhaled, topical, nasal, intravenous and joint-injected steroids, not just tablets.
This is not a technicality. In pooled data, measured adrenal insufficiency was found in around 52% of people receiving intra-articular (joint) injections and around 49% of oral users. Joint injections were the highest-risk route measured. If you are on long-term high-dose inhalers, potent topical steroids, or repeated joint injections, do not conclude this is somebody else's problem.
Why does coming off prednisone feel so bad?
Because your body stopped making its own cortisol while you were on it. Cortisol production runs on a feedback loop. The brain checks the level, and if there is enough, the pituitary gland stops sending out ACTH, the messenger hormone that tells the adrenal glands to make cortisol. No ACTH, no signal. Steroid medication looks like cortisol to that loop. So the brain, seeing plenty, goes quiet, and the adrenal glands, hearing nothing, stop working.
They do not restart the moment you lower the dose. There is a gap, sometimes a long one, where the medication has gone and your own production has not yet come back. During that gap you are functionally short of a hormone that regulates your blood pressure, your blood sugar, your immune response and your ability to handle any physical stress at all. It feels exactly as bad as that sounds.
This is not rare, and it is not a sign you are doing the taper wrong. In pooled data, roughly half of people on long-term oral glucocorticoids have measurable adrenal insufficiency. Not "are at risk of": have it. Risk is generally considered meaningful once treatment has run beyond about 3 to 4 weeks.
Three different things can make you feel awful, and they need opposite responses
This is the most useful thing on this page. "I feel terrible on my taper" is not one problem. It is at least three, they overlap heavily, and the right response to each is different. You cannot reliably tell them apart yourself, and neither can any device. This is precisely why a taper is a doctor's job.
| What it is | What it can feel like | Why it matters | |
|---|---|---|---|
| Adrenal insufficiency | Your own cortisol production has not restarted yet | Deep fatigue, weakness, nausea, dizziness on standing, low blood pressure | Can escalate to an adrenal crisis. This is the one that can kill you |
| Glucocorticoid withdrawal syndrome | A distinct, recognized syndrome from the body adjusting to lower steroid levels, even when cortisol is adequate | Low mood, lethargy, sleeping excessively, muscle and joint pain, headache, nausea, poor appetite. Some literature also reports fever, though the main endocrine guideline does not list it | Genuinely unpleasant, and often mistaken for the disease returning. Never use this box to explain away a fever. Fever during or after a taper needs urgent assessment, because crisis and serious infection both cause it, and steroids can blunt it. Assume the dangerous cause until a doctor says otherwise |
| The original disease flaring | The condition the steroid was treating is coming back as the dose falls | Whatever your condition felt like before treatment | Needs the underlying disease treated. In one small single-centre study, 18% of successful weans (7 of 38) needed a temporary dose increase for a flare before finally stopping. A small number, and it matches what clinicians describe |
Notice the shape of that table. Three causes, similar feelings, and the correct action differs each time: one is an emergency, one may need a slower taper, one may need the disease treated. A number on a screen cannot resolve that, and neither can this article. It is a clinical judgement, made by someone who knows your history.
One more thing steroids hide
Corticosteroids suppress inflammation and blunt the immune response. That is the point of them, and it also means they can mask the usual signs of a serious infection. Do not assume that because you feel roughly as bad as you did last week, nothing new is happening. If you develop a fever, feel suddenly worse, or something simply feels different, get seen.
How long does it take for cortisol to recover?
Longer than most people are told, and it depends on how much and how long.
- Short courses, under about 2 weeks: the axis usually recovers fairly quickly. But note what the evidence does not say. The pooled analysis concluded that there is no dose, duration, route or underlying condition for which adrenal insufficiency can be excluded with certainty. "Usually" is not "always", and repeated short courses, the pattern common in asthma, COPD and gout, are not well covered by any threshold. If you feel unwell after any course, take it seriously.
- Prolonged treatment, especially beyond a year: recovery can take 6 to 12 months.
- The earliest signs of the axis waking up are typically seen around 4 weeks after stopping, with a normal daily rhythm re-establishing later.
- Recovery is slower with higher doses, longer treatment, and if you developed steroid-induced Cushing's syndrome along the way.
- 6 to 12 months is not a ceiling. Around a quarter of people are still suppressed at 6 months after long-term therapy, and in some cases recovery has taken up to 4 years. Two things follow. First, if you are past a year and still struggling, you are not failing and it is not hopeless: the great majority of people do recover. Second, and more importantly, do not treat a date on the calendar as the end of your crisis risk. It ends when your doctor says the axis has recovered, not when you decide enough time has passed.
Recovery is assessed by your doctor with periodic tests, usually a morning cortisol and an ACTH stimulation test. The interval between them is a clinical judgement, and if the wait feels long, that is a reasonable thing to raise at your next appointment.
Can a wearable tell me if my adrenal glands have recovered?
No. We make a cortisol sensor, so let us be the ones to say it plainly.
Recovery of the HPA axis is assessed by a clinician, with a morning cortisol measurement and an ACTH stimulation test that requires an injection and timed blood draws. No consumer device and no at-home kit can perform that test, ours included. A wellness reading is not that test, it is not on the same scale as a clinical blood result, and it cannot be compared to one. Do not try.
More importantly: nothing you read on a wearable should ever change your steroid dose. Taper decisions belong to the doctor who prescribed the steroid, and getting them wrong in either direction is dangerous. If you want to understand the hormone itself and how it moves through a day, that is covered in Cortisol 101.
This page is general medical information, not medical advice, and not a diagnosis. It summarizes published clinical guidance from the sources below. Steroid tapering is managed by qualified healthcare professionals. Never change your dose without speaking to the doctor who prescribed it. If you suspect an adrenal crisis, seek emergency care immediately.
References
- Cleveland Clinic Journal of Medicine. Glucocorticoid-induced adrenal insufficiency and glucocorticoid withdrawal syndrome: two sides of the same coin. 2024.
- Younes AK, Younes NK. Recovery of steroid induced adrenal insufficiency. Translational Pediatrics. 2017.
- Rushworth RL, Torpy DJ, Falhammar H. Adrenal crisis: prevention and management in adult patients. Therapeutic Advances in Endocrinology and Metabolism. 2019.
- StatPearls (NCBI Bookshelf). Adrenal Crisis.
- Broersen LHA, et al. Adrenal insufficiency in corticosteroids use: systematic review and meta-analysis. JCEM. 2015. (Source for the by-route figures, and for the finding that adrenal insufficiency cannot be excluded with certainty for any dose, duration or route.)
- Mehta S, Lazarus J, Sharma R, et al. Glucocorticoid-induced adrenal insufficiency: physiological dose tapering promotes recovery. Endocrine Connections. 2026. (Source for the 18%, 7 of 38 successful weans.)
- NHS England. National Patient Safety Alert: Steroid Emergency Card. 2020.