What Is Cortisol?

Cortisol is a steroid hormone released by the adrenal glands in response to stress. It is essential — it regulates blood sugar, metabolism, immune response and blood pressure. Cortisol naturally peaks in the morning (helping you wake up) and falls throughout the day. The problem is chronic elevation from ongoing stress, poor sleep or lifestyle factors.

Signs of Chronically Elevated Cortisol

  • Difficulty sleeping despite feeling tired
  • Weight gain, particularly around the abdomen
  • Persistent fatigue
  • Increased anxiety or irritability
  • Frequent illness (cortisol suppresses immune function when chronically elevated)
  • Sugar and carbohydrate cravings

Evidence-Based Ways to Lower Cortisol

  1. 1

    Prioritise sleep quality and quantity

    Sleep is the most powerful cortisol regulator. Cortisol levels are elevated by poor sleep and reduced by good sleep in a bidirectional relationship. Consistent 7–9 hours, regular sleep/wake times, and a dark, cool bedroom have the largest impact on normalising cortisol patterns. Even one week of consistent good sleep measurably reduces cortisol levels in chronic stress sufferers.

  2. 2

    Exercise regularly — but not excessively

    Moderate exercise reduces cortisol and improves the stress response system over time. However, very intense or prolonged exercise (over 60–90 minutes at high intensity) actually elevates cortisol acutely. For cortisol management specifically: 30–45 minutes of moderate aerobic exercise (running, cycling, swimming) 3–5 times per week. Strength training also helps. Allow recovery days — overtraining syndrome is associated with chronically elevated cortisol.

  3. 3

    Reduce caffeine — especially afternoon and evening

    Caffeine stimulates cortisol release. A single cup of coffee can elevate cortisol by 30% in non-habitual drinkers. Regular drinkers develop tolerance to the acute effect, but high caffeine intake still disrupts sleep quality (which then elevates cortisol). Cut off caffeine by 2pm for most people to avoid sleep disruption.

  4. 4

    Practice stress-reduction techniques daily

    Mindfulness meditation, deep breathing and yoga all produce measurable reductions in cortisol with consistent practice. Even 10–20 minutes daily of slow, deliberate breathing activates the parasympathetic nervous system and downregulates the HPA axis (the cortisol-producing system). See our guides on daily meditation and natural stress reduction.

  5. 5

    Social connection and laughter

    Positive social interactions and genuine laughter reduce cortisol directly. Studies show cortisol is measurably lower after time with close friends compared to time spent alone under stress. Prioritising social time is not self-indulgent — it is physiologically beneficial.

  6. 6

    Anti-inflammatory diet patterns

    Chronic inflammation elevates cortisol. A Mediterranean-style diet (vegetables, fruit, olive oil, fish, nuts, legumes) reduces systemic inflammation. Limiting processed food, refined sugar and alcohol reduces inflammatory load. Omega-3 fatty acids (oily fish, walnuts, flaxseed) have specific cortisol-reducing evidence.

If you suspect a cortisol disorderCushing’s syndrome (pathologically elevated cortisol) is a medical condition with specific symptoms including facial rounding, purple stretch marks, significant abdominal weight gain and muscle weakness. It requires medical diagnosis and treatment. See a GP if you suspect a medical cause rather than lifestyle-related cortisol elevation.

Frequently Asked Questions

Multiple randomised controlled trials have shown ashwagandha supplementation (300–600mg/day of a root extract like KSM-66) significantly reduces cortisol compared to placebo in chronically stressed adults — reductions of 15–30% are reported in good-quality studies. It is one of the better-evidenced adaptogens. It is generally safe for most adults at studied doses. Consult a GP before supplementing if you have thyroid conditions, autoimmune disease or take medications.
Some changes work quickly: a single meditation session or exercise bout produces measurable acute cortisol reduction. For sustained normalisation of chronically elevated cortisol: consistent sleep improvement shows measurable effects within 1–2 weeks. Regular exercise and stress management practices produce significant cortisol pattern changes within 4–8 weeks of consistent practice. There is no instant fix — but the improvements compound over time.