What Affects My Cortisol?
Updated: Jul 21
The answer might surprise you...
Welcome to the Gut Honest Truth blog where a Certified Functional Medicine Practitioner gives you digestible information to tackle your chronic health concerns.
That's me, Katie Morra; and in this blog I'm going to break down everything you need to know about cortisol — what it actually does, what drives it out of balance, and how to start supporting it.
And as always, working one-on-one for your specific needs is always our top recommendation, check out our appointment options to get started with one of our licensed health care professionals today.
What Is Cortisol?
Cortisol is often called the primary stress hormone — but that label dramatically undersells what it actually does. Cortisol is a glucocorticoid (steroid hormone) produced from cholesterol by the adrenal glands, and it's a primary product of the Hypothalamic-Pituitary-Adrenal (HPA) Axis — your body's main stress response system.
Contrary to popular belief, cortisol is not inherently negative. The body relies on it for a wide range of normal physiological functions, most of which exist to protect you. Problems arise only when cortisol levels are too high or too low — or at the wrong times of day.
Where Is Cortisol Produced?
Cortisol is made by your adrenal glands — two small, triangular-shaped glands that sit atop each kidney. Despite their size, these glands regulate a remarkable range of functions including immune response, energy, sex drive, hormone cycles, fertility, fat storage, and blood sugar regulation.
The adrenal glands also produce DHEA, aldosterone, adrenaline, and noradrenaline — making them central players in your overall hormonal health.
What Does Cortisol Actually Do?
Cortisol communicates with virtually every system in the body. Its main functions include:
Blood pressure regulation
Bone density maintenance
Reducing inflammation
Raising blood sugar
Regulating metabolism
Influencing memory formation
Influencing insulin sensitivity
Influencing fat distribution
Supporting energy levels
Indirectly impacting digestion
Cortisol follows a diurnal cycle — it should be highest in the morning, decline throughout the day, and reach its lowest point at bedtime. One important feature is the cortisol awakening response (CAR): cortisol surges in the first 30-45 minutes after waking, signaling the body to prepare for the day. A healthy CAR means you wake up alert and motivated. A flat CAR often looks like morning grogginess, fatigue, and low motivation that lingers well into the day.
High vs. Low Cortisol — What's the Difference?
Both patterns reflect your body's stress response — but at different stages.
High cortisol generally indicates an acute stress response. Your body is running at full speed but hasn't been doing so for long enough to deplete resources. This is often modifiable with lifestyle support.
Low cortisol generally means your adrenal glands have been overproducing cortisol for an extended period and can no longer keep up with demand. They've essentially burned out. Low cortisol can be broken down into 4 progressive stages of fatigue — the last being complete exhaustion.
It's worth noting that actual clinical conditions — Cushing's disease (extremely high cortisol) and Addison's disease (extremely low cortisol) — are distinct from functional cortisol dysregulation and require medical supervision.
Symptoms of high cortisol:
Anxiety and depression
Weight gain, particularly belly fat
Sleep disruption or second wind at night
Waking in the middle of the night
Muscle weakness
Thinning skin or hair
High blood pressure
Low sex drive
Memory issues
Digestive difficulty
Symptoms of low cortisol:
Fatigue and afternoon energy crashes
Salt and sugar cravings
Frequent illness
Joint and muscle pain
Low blood pressure or dizziness
Increased thirst
Depression and low mood
Low blood sugar
Cortisol and Your Circadian Rhythm
Your circadian rhythm is your body's internal 24-hour clock, regulated by a group of neurons in the hypothalamus called the suprachiasmatic nucleus (SCN). It governs sleep and wake cycles, hormone release, digestion, hunger, and body temperature.
Because cortisol follows a diurnal pattern — peaking in the morning and falling through the day — it directly influences your circadian rhythm. When cortisol is dysregulated, sleep quality, energy, and overall health suffer downstream.
5 ways to support your circadian rhythm:
Keep a consistent sleep and wake schedule
Get light exposure within 20 minutes of waking — ideally sunlight
Stop caffeine 8-10 hours before bed
Prioritize nutrition, movement, and stress management
Test your cortisol levels to understand your personal pattern
Root Causes of Cortisol Imbalance
Chronic Stress
In an acute threat, the body prepares to fight or flee — cortisol surges, blood and energy rush to the extremities, and non-essential functions like digestion, reproduction, and immune defense are suppressed. The problem is that our nervous systems haven't evolved to differentiate a genuine emergency from everyday stressors. Traffic, a tense meeting, a difficult conversation — all of these trigger the same primal cortisol response.
Chronically unmanaged stress is the most common driver of cortisol dysregulation we see in practice. The downstream effects touch everything from gut health to thyroid function to hormone balance.
Thyroid Dysfunction
Elevated cortisol raises thyroid binding globulin, which reduces the free thyroid hormone available to your cells. It also impairs the conversion of T4 to T3 (the active form) and increases conversion to Reverse T3 (the inactive form). The net result: elevated cortisol can functionally suppress thyroid function — even when thyroid labs look normal on paper.
This is one of the most important reasons we always look at cortisol and thyroid together, not in isolation. Learn more about understanding thyroid lab markers here.
Under-Eating
When the body isn't given adequate calories to generate energy, it defaults to cortisol to keep things running. This works short-term — but chronic under-eating drives sustained cortisol elevation, eventually leading to adrenal exhaustion. Adequate nutrition is one of the most direct ways to support healthy cortisol production.
How We Test Cortisol at GHT
The best way to understand your cortisol pattern is through a DUTCH Complete or DUTCH Adrenal test — a dried urine test that captures cortisol at multiple points throughout the day, giving us a full picture of your diurnal rhythm, cortisol awakening response, and metabolite levels. Standard blood cortisol tests are a single snapshot and often miss the nuance of how your cortisol is functioning across the day.
Top Supplements for Supporting Cortisol
These adaptogenic herbs have solid research behind them for supporting HPA Axis function:
Ashwagandha
Holy Basil
Maca
Reishi
Rhodiola
Schisandra
Shatavari
As always, supplement protocols should be tailored to your specific cortisol pattern — what supports high cortisol is different from what supports low cortisol. This is one area where testing before supplementing makes a significant difference.
Cortisol gets a bad rap — but it's an essential hormone doing critical work every day. The goal isn't to eliminate cortisol. It's to understand your personal pattern, identify what's driving it out of balance, and support your body accordingly.
Ready to find out what your cortisol is actually doing? Schedule a free discovery call here.
Comments