Adrenal cortex supplements are dietary supplements made from the outer layer of adrenal glands taken from cows or pigs. They belong to a category called “glandulars,” products built on the idea that consuming animal organ tissue supports the corresponding organ in your body. These supplements are most commonly marketed to people experiencing chronic fatigue, stress, or what alternative practitioners call “adrenal fatigue,” a diagnosis that mainstream endocrinology does not recognize.
What’s Actually in Them
Your adrenal glands have two distinct parts. The outer layer, the cortex, produces steroid hormones: cortisol (your main stress hormone), aldosterone (which regulates blood pressure and electrolytes), and small amounts of sex hormones. The inner layer, the medulla, produces adrenaline and noradrenaline. Adrenal cortex supplements use only the outer layer, which means they should theoretically be free of adrenaline. Whole adrenal glandulars, by contrast, include both layers.
The source animals are typically cattle or pigs. Manufacturers dry and process the gland tissue into capsules, with commercial doses ranging from about 50 mg to 350 mg per capsule. Many brands claim their products are “hormone-free,” but that claim doesn’t hold up well under testing.
Hidden Hormones Are a Real Problem
A 2018 study analyzed 12 supplements marketed for adrenal support and found that most contained active steroid hormones that weren’t listed on the label. Pregnenolone, a precursor to cortisol and sex hormones, appeared in 42% of the products tested. A quarter contained budesonide, a potent anti-inflammatory steroid. Others contained androstenedione (a testosterone precursor), cortisol itself, cortisone, or another steroid called 17-hydroxyprogesterone.
This matters because taking steroid hormones without knowing it can have serious consequences. If a supplement delivers enough cortisol or cortisol-like compounds over time, your body’s own cortisol production can shut down. Stopping the supplement suddenly could then trigger genuine adrenal insufficiency, a condition where your body can’t produce enough cortisol on its own. In some cases, prolonged hidden steroid exposure has led to Cushing syndrome, a condition marked by weight gain, high blood sugar, weakened bones, and a characteristic rounding of the face.
Because these are dietary supplements rather than drugs, the FDA does not require manufacturers to prove they work or to verify the exact hormone content before selling them. There is no standardized testing protocol that guarantees a product is truly hormone-free.
The “Adrenal Fatigue” Question
Most people who find these supplements are searching for relief from persistent tiredness, brain fog, or feeling burned out. Alternative health practitioners often attribute these symptoms to overworked adrenal glands that can no longer keep up with the body’s demand for cortisol. The proposed solution: feed the adrenals with glandular tissue to help them recover.
The Endocrine Society, the leading professional organization for hormone specialists, has stated clearly that adrenal fatigue is not a recognized medical diagnosis. There is no validated test for it. Blood or saliva cortisol tests sometimes offered by alternative practitioners are not supported by good scientific evidence, and the results can be misleading. The symptoms commonly labeled as adrenal fatigue, including exhaustion, sleep problems, difficulty concentrating, and salt or sugar cravings, overlap with dozens of well-established conditions: thyroid disorders, sleep apnea, depression, iron deficiency, and actual adrenal insufficiency (Addison’s disease), among others.
The concern from endocrinologists is that accepting an unproven diagnosis delays the identification of something treatable. A person with undiagnosed sleep apnea or hypothyroidism, for example, could spend months or years taking glandular supplements while the real problem goes unaddressed.
Safety and Contamination Risks
Beyond the hidden hormone issue, bovine-derived supplements carry a theoretical risk related to bovine spongiform encephalopathy, commonly known as mad cow disease. The FDA has a final rule prohibiting certain cattle materials in human food and dietary supplements, specifically brain, spinal cord, skull, eyes, and several other nervous system tissues from cattle over 30 months old. Adrenal glands are not on the prohibited list, but the regulatory framework relies on manufacturers correctly sourcing and processing their materials. There is no pre-market inspection system to verify compliance.
Side effects reported by users vary widely. Some people notice nothing at all. Others report jitteriness, sleep disruption, or changes in mood. Because the actual hormone content of any given product is unknown, the side effect profile is essentially unpredictable. Two capsules from different brands, both labeled “adrenal cortex 250 mg,” could contain very different amounts of active hormones.
What the Evidence Actually Supports
There are no well-designed clinical trials showing that adrenal cortex supplements improve energy, reduce stress, or restore adrenal function in people without a diagnosed adrenal disease. The theoretical basis, that eating animal gland tissue supports the corresponding human gland, dates back to early 20th-century organ therapy and has not been validated by modern research. Your digestive system breaks proteins down into amino acids; there is no established mechanism by which swallowed adrenal tissue would selectively nourish your adrenal glands.
For people with confirmed adrenal insufficiency (a condition diagnosed through specific hormone testing by an endocrinologist), the standard treatment is prescription hormone replacement with precise, measured doses. Over-the-counter glandulars are not a substitute because their hormone content is neither consistent nor predictable.
If persistent fatigue is driving your interest in these supplements, the most productive path is a thorough workup that includes thyroid function, iron and ferritin levels, vitamin D, blood sugar, and a sleep evaluation. These are all common, treatable causes of the exact symptoms that get labeled “adrenal fatigue,” and each one has an evidence-based solution.