Cortisol Is Not the Enemy — What It Actually Does

You’ve seen the posts: a TikTok creator blaming cortisol for belly fat, a wellness brand selling an “adrenal support” supplement to fix your “cortisol spike,” a caption explaining that your exhaustion, your cravings, your puffy face — all cortisol’s fault. In South Africa, Google Trends data consistently shows spikes in searches for “cortisol supplements” and “lower cortisol naturally,” driven almost entirely by social media content, not clinical concern.

Before you spend R350 on an adaptogen capsule, here’s what this hormone actually does — and why the wellness industry’s version of the story is missing most of the science.

The cortisol myth worth naming first

The narrative that spread widest came from a loose interpretation of Hans Selye’s mid-20th-century stress research, combined with more recent (and frequently misapplied) studies linking cortisol to abdominal fat storage. Several 2000s-era studies showed that people with genuinely elevated cortisol — due to a rare condition called Cushing’s syndrome — gained central fat and had metabolic disruption. Wellness influencers then reverse-engineered this: if pathologically high cortisol causes those symptoms, they reasoned, perhaps ordinary life stress is causing a milder version of the same problem.

The logic sounds plausible. It is also largely unsupported. Healthy adults under normal life stress do not sustain the kind of cortisol elevation seen in Cushing’s syndrome — a condition affecting roughly 10 to 15 people per million per year worldwide. No local SA data on Cushing’s prevalence exists, but endocrinologists at Groote Schuur Hospital and Charlotte Maxeke Johannesburg Academic Hospital see it as genuinely uncommon. The jump from “stress raises cortisol briefly” to “your cortisol is chronically high and damaging your body” is not supported by mainstream endocrinology.

What cortisol is actually doing right now

Cortisol is a glucocorticoid hormone produced by the adrenal glands, which sit on top of each kidney. It operates on a precise 24-hour rhythm controlled by the hypothalamic-pituitary-adrenal (HPA) axis — a feedback loop between your brain and your adrenal glands.

Here is what it is managing at this moment:

Blood sugar regulation. Cortisol signals the liver to release glucose into the bloodstream, raising blood sugar when your body needs fuel — during exercise, on waking, or when you haven’t eaten. This is not a malfunction; it is the mechanism that keeps your brain supplied with energy between meals. For the roughly 4.2 million South Africans living with type 2 diabetes (per the 2023 International Diabetes Federation Atlas), cortisol’s glucose-raising effect is worth understanding because it can complicate blood sugar management — but that is a clinical conversation with a doctor, not a reason to suppress cortisol with supplements.

Immune modulation. Cortisol is anti-inflammatory. At normal physiological concentrations, it prevents the immune system from overreacting — which is why synthetic versions of cortisol (like prednisone) are prescribed for conditions ranging from asthma to lupus. SA’s National Health Insurance planning documents identify autoimmune and inflammatory conditions as a growing burden, and corticosteroid therapy remains a cornerstone of public-sector management of these conditions.

The sleep-wake cycle. Cortisol peaks about 30 to 45 minutes after waking — a phenomenon researchers call the cortisol awakening response (CAR). This morning surge is what helps you feel alert. It then falls gradually across the day, reaching its lowest point around midnight. Disrupting this rhythm — through shift work, irregular sleep, or load-shedding-related night-time light exposure — genuinely does affect mood, cognition, and metabolic health. This is a real mechanism worth addressing, and it requires sleep hygiene, not supplements.

Blood pressure support. Cortisol helps maintain vascular tone. Too little cortisol — not too much — causes dangerously low blood pressure. This is what happens in Addison’s disease, a condition of adrenal insufficiency that is notably more common in people with HIV or TB, both priority conditions in South Africa’s public health burden.

When cortisol actually is a problem

Sustained, clinically significant cortisol elevation is real — but it is not what most social media posts describe.

Cushing’s syndrome involves a tumour (usually on the pituitary or adrenal gland) that drives cortisol production far above any stress response. Symptoms include a distinctive fat pad at the back of the neck, a rounded “moon face,” purple stretch marks, and muscle weakness. This is diagnosed with a 24-hour urinary free cortisol test or a late-night salivary cortisol test — not a supplement quiz. If your GP suspects Cushing’s, they will refer you to an endocrinologist.

Chronic psychological stress does sustain mildly elevated cortisol over time, and research from the South African Medical Research Council (SAMRC) has documented high allostatic load — the cumulative biological cost of chronic stress — in communities dealing with poverty, violence, and structural inequality. This is a genuine public health concern. But the solution is not an adaptogen. Evidence-based responses include structured psychological support (SADAG offers free counselling at 0800 567 567), sleep prioritisation, physical activity, and, where appropriate, medication for anxiety or depression under medical supervision.

HPA axis dysregulation after major illness — including severe COVID-19 — has been documented in peer-reviewed literature, including work published in the South African Medical Journal. Some long-COVID patients show altered cortisol rhythms. This warrants clinical investigation, not self-treatment.

What the “adrenal fatigue” concept gets wrong

“Adrenal fatigue” — the idea that chronic stress exhausts the adrenal glands, causing low-grade cortisol deficiency — is not a recognised medical diagnosis. The Endocrine Society explicitly states that no scientific evidence supports it as a distinct condition. No South African endocrinology body has endorsed it either.

This matters because the supplements sold to treat it (typically ashwagandha, rhodiola, liquorice root, or proprietary “adrenal blends”) cost between R200 and R600 per month in SA health stores, carry real drug interactions (liquorice root raises blood pressure; some adaptogens interact with antiretrovirals), and have not been tested against a placebo in rigorous South African trials.

If you are genuinely exhausted and unwell, the cause is worth investigating properly — thyroid dysfunction, iron deficiency anaemia, sleep apnoea, depression, and HIV-associated fatigue are all common in South Africa and all diagnosable through standard blood tests available at public clinics and private GPs alike.

Getting access to real answers

Accessing care in South Africa

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Public sector: Start at your nearest community health centre (CHC). GPs and nurses can order a basic cortisol blood test if clinically indicated. If Cushing’s or Addison’s disease is suspected, you’ll be referred to the endocrinology department at your nearest academic hospital (such as Groote Schuur, Charlotte Maxeke, or Inkosi Albert Luthuli). Referral is free within the public system.

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Private sector: A GP consultation costs roughly R600–R900. A serum cortisol blood test at a private lab (Lancet, Ampath) runs approximately R350–R500 without medical aid. A specialist endocrinologist consultation typically starts at R1,200–R1,800.

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Medical aid: Adrenal disorders (Addison’s disease, Cushing’s syndrome) qualify as Prescribed Minimum Benefit (PMB) conditions under the Medical Schemes Act, meaning your scheme cannot refuse to cover diagnosis and treatment costs. Check with your scheme directly about pre-authorisation requirements.

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Practical barrier: Load-shedding affects refrigerated sample transport in some areas, which can delay lab results. Ask your GP or clinic whether your sample needs special handling and whether to book a morning appointment (when cortisol testing is most clinically useful).

What healthy cortisol management actually looks like

Rather than suppressing cortisol with supplements, supporting its natural rhythm is straightforward:

• Sleep consistency is the most powerful lever. Going to bed and waking at the same time daily strengthens the HPA axis rhythm. This matters especially for South Africans doing night-shift work or managing load-shedding disruption.
• Morning light exposure within 30 minutes of waking reinforces the cortisol awakening response and improves daytime alertness — free, immediate, and evidence-backed.
• Physical activity reduces baseline cortisol reactivity over time. Even 30 minutes of moderate walking five days a week produces measurable improvement in stress hormone regulation, per meta-analyses reviewed by the SAMRC.
• Rooibos tea has been studied in small South African trials (notably at Stellenbosch University) for its potential to modestly reduce salivary cortisol post-stress. Effect sizes are small and evidence is preliminary — but it is a safe, affordable, and culturally familiar option that carries no drug interactions.
• Eating regularly prevents the blood-sugar dips that trigger sharp cortisol surges. Traditional foods like pap with morogo, amasi, and samp-based meals provide sustained energy release — no expensive “cortisol-balancing” diet required.

When to see a doctor

Book a GP appointment if you have: unexplained weight gain concentrated around your abdomen and upper back; easy bruising with no clear cause; purple or reddish stretch marks on the abdomen or thighs; persistent muscle weakness; extreme fatigue not explained by sleep or workload; or very low blood pressure with dizziness on standing. These symptoms warrant clinical investigation — not a supplement.

Bottom line

• Cortisol regulates blood sugar, immune response, blood pressure, and your sleep-wake cycle — it is essential, not pathological.
• The “chronically high cortisol” narrative driving supplement sales is based on a misapplication of research on a rare tumour condition.
• “Adrenal fatigue” is not a recognised medical diagnosis; no SA or international endocrinology body endorses it.
• Genuine cortisol disorders (Cushing’s, Addison’s) are diagnosable and treatable through the public or private system — Addison’s is more common in people living with HIV or TB.
• Support your cortisol rhythm with sleep consistency, morning light, regular meals, and movement — and save your rands.