The cortisol obsession of 2025–26 has gone too far. Here's what cortisol actually does, why "belly fat from stress" is mostly nonsense, and what genuinely helps if you feel chronically wired.
Open any wellness app and you'll be told that cortisol — your "stress hormone" — is the culprit behind your belly fat, your bad sleep, your puffy face, your anxiety, and your inability to lose weight. There's a whole supplement category aimed at "cortisol-lowering" and "adrenal support."
Some of this is reasonable. Most of it isn't. The popular cortisol narrative leans heavily on one thing being true at the extreme (severe Cushing's syndrome) and assumes every twitchy, tired, slightly-soft-around-the-middle person has the same problem. They don't.
This is a pharmacist's take on cortisol — what it does, what's actually testable, and what helps.
What cortisol actually does
Cortisol is a glucocorticoid hormone made by the adrenal glands, regulated by the hypothalamic-pituitary-adrenal (HPA) axis. It's not the villain of biology — it's vital.
Cortisol does several useful things:
- Wakes you up in the morning (the cortisol awakening response, or CAR)
- Mobilises glucose from stored glycogen so you have energy
- Modulates the immune system — both ramps it up and tamps it down depending on context
- Helps regulate blood pressure
- Allows you to respond to acute stress — by sharpening focus, mobilising fuel, and prioritising short-term survival
You don't want low cortisol any more than you want chronically high. The natural rhythm is a sharp peak about 30 minutes after waking, gradually tapering through the day to a low point around midnight. Healthy means rhythmic, not absent.
What "high cortisol" actually means
Genuinely chronic high cortisol — Cushing's syndrome — is rare. It's diagnosed by elevated 24-hour urine cortisol, midnight saliva cortisol, or failure of overnight dexamethasone suppression. People with Cushing's get distinctive physical signs: a rounded "moon face," fat redistribution to the trunk and back of the neck ("buffalo hump"), purple stretch marks, thin skin, easy bruising, muscle wasting in the limbs.
If you don't have those specific physical signs, you almost certainly don't have clinically high cortisol — even if you feel stressed.
What people often confuse with high cortisol is a disrupted cortisol rhythm — too high at bedtime, too low in the morning, or a flat curve. This is mostly driven by sleep disruption, alcohol, chronic stress, shift work, and inflammation. It's real, but it's not "you have too much cortisol overall."
The "belly fat from stress" claim
Let's address this one head-on because it drives so much supplement marketing. The claim is that chronic stress raises cortisol, which causes fat to deposit specifically around your midsection.
The reality is more nuanced:
- In Cushing's syndrome, trunk fat redistribution is real and dramatic. But that's a clinical condition.
- In the general population, the correlation between perceived stress and belly fat is mostly mediated by sleep loss, increased food intake (especially refined carbs and alcohol), and reduced activity — not directly by cortisol levels themselves.
- Lowering cortisol alone, without fixing sleep and intake, doesn't reliably reduce visceral fat.
So the "cortisol calmer" supplement you're considering — even if it does modestly lower cortisol — is unlikely to give you a flat stomach unless your sleep, eating, and activity are also in place.
Pharmacist tip
If your bedtime cortisol is high and disrupting sleep, the fix is often boring and free: consistent sleep timing, dark room, no alcohol within 3 hours of bed, dinner at least 3 hours before bed. Try a fortnight of that before reaching for an adaptogen complex.
What you can actually test
If you genuinely suspect a cortisol issue:
- Morning serum cortisol — single timed blood draw, useful as a starting point. Should be high in the morning; low or flat suggests adrenal insufficiency.
- 4-point saliva cortisol — measures the rhythm across the day. More informative than a single blood draw. Marketed heavily by integrative clinics, but interpretation is genuinely useful when read by someone who knows what they're doing.
- 24-hour urinary free cortisol — the gold standard for assessing total cortisol production, used in suspected Cushing's.
- ACTH stimulation test or dexamethasone suppression test — only relevant for clinical adrenal dysfunction, ordered by specialists.
"Adrenal fatigue," as marketed by supplement brands, is not a recognised medical diagnosis. Subclinical HPA axis dysfunction is real, but it's not "your adrenals are tired and just need pills."
What actually helps if you feel "stressed and wired"
The boring answers work. The exciting ones mostly don't.
What works (high-confidence)
- Sleep, properly — 7+ hours, consistent timing. Single biggest cortisol-normaliser in existence.
- Daylight in the morning — 10 minutes outside within an hour of waking helps anchor your cortisol awakening response.
- Limit alcohol — alcohol disrupts both REM sleep and overnight cortisol. The fitness influencer who tells you to ditch alcohol for two weeks is annoying but correct.
- Adequate protein and reasonable refined-carb intake — blood sugar swings drive cortisol spikes.
- Walking and weight training — both reduce baseline stress reactivity. High-intensity cardio done late at night will raise evening cortisol.
What helps for some (modest evidence)
- Ashwagandha (KSM-66 or Sensoril) — meta-analyses show modest cortisol-lowering effects and improvements in perceived stress. Worth a 6–8 week trial.
- Magnesium glycinate — helps with the downstream consequences (sleep, muscle relaxation, calmness) even if it doesn't directly lower cortisol.
- L-theanine — promotes alpha brain waves and feels calming; small effect.
- Rhodiola — for acute stress and fatigue. Effects are mild.
What's mostly hype
- "Adrenal support" multi-blends with 12 ingredients in homeopathic doses
- "Cortisol calmer" gummies — typically very low doses of one or two ingredients
- Adaptogen mushroom powders sold for stress when you've never tested cortisol
- Anything claiming to "reset your cortisol curve" without a sleep intervention
What this means for you
Stop spending money on "cortisol calmers" until you've got the basics in place. Sleep, daylight, protein, walking, less alcohol — these fix more cortisol-related symptoms than any supplement on the market. If those are in place and you still feel wired, ashwagandha and magnesium glycinate are the two evidence-based supplements worth a 6–8 week trial. Beyond that, if you have actual symptoms of adrenal dysfunction (extreme fatigue, low blood pressure, salt cravings), that's a conversation with a GP, not a supplement aisle.
If you'd like a pharmacist's view on what to try, send us a message and we'll reply within one working day with a tailored recommendation.
