Cortisol increases through a chain reaction that starts in your brain: your hypothalamus releases a signaling hormone, which tells your pituitary gland to release another hormone, which finally triggers your adrenal glands to produce cortisol. If your levels are genuinely low, the approach to raising them depends on whether you’re dealing with a medical condition like adrenal insufficiency or simply trying to optimize a sluggish hormonal rhythm. Normal morning cortisol falls between 7 and 25 mcg/dL, dropping to 2 to 14 mcg/dL by evening.
Why Your Cortisol Might Be Low
Cortisol follows a tight daily rhythm. It peaks in the morning near your usual wake time, declines throughout the day, hits its lowest point in the early evening, then gradually climbs again overnight. Anything that disrupts this cycle can flatten your levels. Chronic circadian misalignment, like rotating shift work or an erratic sleep schedule, has been shown to significantly reduce 24-hour cortisol output. Ironically, a single night of total sleep deprivation temporarily spikes cortisol, but sustained disruption does the opposite.
The more serious cause is adrenal insufficiency, a condition where the adrenal glands can’t produce enough cortisol on their own. In primary adrenal insufficiency (Addison’s disease), the adrenal glands themselves are damaged, often by an autoimmune process. In secondary adrenal insufficiency, the pituitary gland fails to send the right signals. Both produce a recognizable set of symptoms: chronic fatigue, muscle weakness, loss of appetite, unexplained weight loss, and abdominal pain. More subtle signs include craving salty foods, dizziness when standing, irritability, depression, low blood sugar, and irregular periods. People with Addison’s disease often develop darkened skin on scars, skin folds, knuckles, elbows, and the inside of the cheeks.
Getting Tested
A simple blood draw can measure your serum cortisol, but timing matters. Morning samples should fall between 7 and 25 mcg/dL, and afternoon samples between 2 and 14 mcg/dL. Because cortisol fluctuates so much throughout the day, a single reading isn’t always definitive.
The more precise test is the ACTH stimulation test, where you’re given a synthetic version of the hormone that normally tells your adrenal glands to produce cortisol. Your blood is drawn before and after the injection. A peak cortisol level of 18 mcg/dL or higher is traditionally considered a passing response, though newer, more sensitive lab assays have suggested a lower cutoff of 14 mcg/dL may be more appropriate. If your adrenals can’t mount this response, it confirms adrenal insufficiency.
Medical Treatment for Adrenal Insufficiency
When your body can’t make enough cortisol, the standard treatment is replacing it directly with oral hydrocortisone, typically 15 to 25 mg per day split into two to four doses. The doses are staggered to mimic your body’s natural rhythm, with the largest dose taken in the morning. People with primary adrenal insufficiency also often need a second medication to replace aldosterone, a related hormone that helps regulate salt and fluid balance.
This is lifelong replacement therapy, not a short-term fix. You’ll carry an emergency plan for “sick days,” because your body can’t ramp up cortisol production during illness or physical stress the way a healthy person’s would. Dose adjustments happen under close medical supervision since both too little and too much replacement cortisol cause problems.
Exercise and Cortisol
Exercise is a physical stressor, and your body responds to it by releasing cortisol. High-intensity interval training and prolonged intense cardio produce the biggest spikes. This is a normal, healthy part of the stress response, and the temporary elevation helps mobilize energy and manage inflammation during recovery.
If your goal is to nudge cortisol upward, intense exercise is one of the most reliable natural triggers. But the spike is temporary, peaking during and shortly after the workout, then returning to baseline. Stanford Lifestyle Medicine recommends limiting high-intensity sessions to two or three times per week with adequate rest between them, since chronically elevated cortisol from overtraining creates its own set of problems.
Caffeine’s Effect on Cortisol
Caffeine reliably raises cortisol, but only if you’re not a regular consumer. After five days of caffeine abstinence, a single dose produces a robust cortisol increase that lasts throughout the day. Regular intake at 300 to 600 mg per day (roughly three to six cups of coffee) blunts this morning response almost entirely, though an afternoon dose can still push cortisol up during the midday hours before levels settle back down by evening.
This means caffeine is not a practical long-term strategy for raising cortisol. Your body adapts quickly, and you’d need to cycle on and off to maintain the effect. For someone with clinically low cortisol, caffeine won’t substitute for proper treatment.
Licorice Root and Cortisol Retention
Licorice root doesn’t increase cortisol production, but it can increase the amount of active cortisol circulating in your body. It works by blocking an enzyme that normally converts cortisol into its inactive form, cortisone. The active compound, glycyrrhizic acid, is broken down in the gut into a molecule that inhibits this conversion, particularly in the kidneys.
The result is that cortisol sticks around longer and in higher concentrations, especially in tissues where it can activate receptors meant for aldosterone. This is why excessive licorice consumption can cause high blood pressure, fluid retention, and low potassium. It’s a real pharmacological effect. Some people with mild cortisol issues use licorice root supplements for this reason, but the margin between a helpful dose and one that causes side effects is narrow.
Grapefruit Juice and Cortisol Metabolism
Grapefruit juice slows the breakdown of cortisol through a different mechanism. It inhibits a liver enzyme responsible for metabolizing cortisol, which results in more cortisol being excreted in its active form rather than being converted to inactive metabolites. Studies in healthy men showed a dose-dependent effect: more grapefruit juice led to a higher ratio of active cortisol to inactive cortisone in urine.
Like licorice, this doesn’t make your adrenal glands produce more cortisol. It simply slows the rate at which your body clears the cortisol you already have. The practical impact for someone with normal adrenal function is modest, but it’s worth knowing if you’re taking hydrocortisone or other medications that interact with the same enzyme pathway.
Sleep and Circadian Rhythm
Keeping a consistent sleep-wake schedule is one of the simplest ways to support healthy cortisol rhythms. People who maintain normal circadian alignment, going to bed and waking at roughly the same time each day, show stable cortisol patterns with little drift. Those with chronic circadian misalignment see their overall 24-hour cortisol decline.
If you suspect low cortisol but haven’t been diagnosed with adrenal insufficiency, fixing your sleep schedule is the first thing worth trying. Wake at the same time every day, get bright light exposure in the morning, and avoid shifting your schedule by more than an hour on weekends. This won’t fix a genuine adrenal problem, but it can restore a blunted morning cortisol peak caused by lifestyle factors alone.