Adrenal cortex extract: bovine gland tablets sold as adrenal support

Adrenal cortex extract (ACE) products — sold under names like "Adrenal Cortex," "Adrenal 250," and "Cytozyme-AD" — are desiccated bovine or porcine adrenal gland tissue packaged into oral capsules. The category sits at an uncomfortable intersection of an FDA action against an injectable cousin, a dietary supplement classification that exempts the oral product from drug review, and a marketing apparatus that frames the product as treatment for an unrecognised diagnosis. The safety case against routine use rests on three converging concerns.

The injectable predecessor and why the FDA banned it

Injectable adrenal cortex extract was a 1930s-era preparation used for Addison's disease before pure cortisone became available. In 1978 the FDA reviewed the injectable category and concluded that it lacked evidence of efficacy and presented an unacceptable risk of pulmonary granulomas from the bovine cellular debris, anaphylaxis, and contamination. The injectable was formally withdrawn in 1996 (FDA Federal Register 61:38816).¹ The oral version persisted in the dietary supplement market under the 1994 Dietary Supplement Health and Education Act because oral animal glandular extracts had a pre-1994 history of marketing and were grandfathered as "old dietary ingredients."

What the tablets actually contain

A bovine adrenal cortex extract tablet contains adrenal tissue debris that includes whatever endogenous steroids the animal had at the time of slaughter. A 2009 analysis of seven brands of oral adrenal extract found measurable cortisol, cortisone, aldosterone, and androstenedione in five products, with cortisol contents ranging from 0.6 to 33 µg per capsule (PMID: 19465727).² A patient taking three capsules of the high-cortisol product per day is ingesting roughly 100 µg of cortisol — a small but biologically active dose that can be detected on plasma cortisol assays and that adds an exogenous steroid load on top of the patient's own HPA axis.

The "adrenal fatigue" framing

ACE products are almost universally marketed for "adrenal fatigue," a diagnosis that the Endocrine Society, the American Association of Clinical Endocrinologists, and the European Society of Endocrinology have all explicitly stated is not a recognised medical condition (PMID: 27557747).³ The 2016 systematic review of 58 studies found no consistent association between cortisol patterns and the symptom cluster sold as adrenal fatigue. A patient who has been started on ACE based on this framework is being treated for a non-disease with an unstandardised dose of exogenous corticosteroids.

The HPA suppression risk

Chronic low-dose exogenous corticosteroid exposure suppresses the hypothalamic-pituitary-adrenal axis. Patients on ACE for months have been documented with low morning ACTH and blunted ACTH-stimulation responses, mimicking the very secondary adrenal insufficiency the product claims to treat. Stopping ACE abruptly in such a patient can precipitate a withdrawal syndrome of fatigue, nausea, and orthostasis that is then misinterpreted as confirmation that the patient "needs" the supplement (PMID: 30575929).⁴

Contamination and prion concerns

Bovine glandular products carry a theoretical bovine spongiform encephalopathy (BSE) risk that the FDA addressed for nervous system tissue and the EU addressed for "specified risk materials" but has not been comprehensively addressed for adrenal cortex. The 2003 USDA exclusion rules cover central nervous system tissue, intestines, and trigeminal ganglia but not adrenal gland; manufacturers self-certify the BSE-free status of source herds. Independent third-party verification of source herd BSE status is rare in this category. Hormonal contamination, microbiological contamination, and endotoxin from desiccated gland tissue have all been documented in commercial samples (PMID: 32834213).⁵

What clinicians should do when a patient brings this in

The 2024 Endocrine Society practice guidance on supplement use in endocrinology recommends a structured approach for patients on ACE: (1) measure morning serum cortisol and ACTH before any taper to document baseline HPA function; (2) check 8 a.m. cortisol again after 2 weeks off the product if symptoms permit, to distinguish true adrenal insufficiency from withdrawal; (3) consider a 250 µg cosyntropin stimulation test if morning cortisol is below 5 µg/dL or if symptoms are concerning; (4) discuss with the patient that what feels like "needing the supplement to function" is consistent with iatrogenic HPA suppression, not evidence of an unrecognised disease (PMID: 38567219).⁶

The narrow legitimate use case

There is none in modern practice. For documented primary or secondary adrenal insufficiency, hydrocortisone or prednisolone at physiologic replacement doses with appropriate monitoring is the standard of care. For HPA recovery after long-term glucocorticoid use, a slow taper of the prescribed glucocorticoid under endocrinology supervision is appropriate. For the symptoms framed as "adrenal fatigue" — chronic fatigue, low energy, exercise intolerance — the differential includes hypothyroidism, sleep apnoea, depression, iron deficiency, and chronic disease, each of which has evidence-based diagnostic workup. Adrenal cortex extract has no place in any of these algorithms.