Plenadren or Efmody?

Same hormone. Different clocks.

How two modified-release hydrocortisone medicines try to return cortisol to the right hour—and why timing may matter as much as dose.

Two medicines, one molecule—and two very different approaches to the 24-hour cortisol rhythm.

THE SHORT ANSWER  Both medicines contain hydrocortisone. Plenadren is taken on waking and recreates cortisol mainly during the day. Efmody is taken at bedtime and again in the morning, allowing cortisol to begin rising before waking. In a short head-to-head trial in primary adrenal insufficiency, Efmody produced a more physiological waking cortisol level and improved several measures of fatigue and quality of life. That is promising—but it does not mean that Efmody is automatically best for every person.

The puzzle: if the ingredient is identical, why should the brand matter?

At first glance, comparing Plenadren with Efmody sounds rather like comparing two bottles of water. Both contain hydrocortisone—the pharmaceutical version of cortisol. Surely 20 mg is 20 mg?

Chemically, yes. Biologically, not quite.

Hormones are messages, and the body pays attention not only to what the message says, but also to when it arrives. A doorbell at two in the afternoon is ordinary. The same doorbell at three in the morning becomes a plot.

That is the central difference between these medicines. Their coatings and internal structures release the same hormone on different timetables. Plenadren waits for you to wake and swallow it. Efmody is designed so that a bedtime dose can begin releasing hydrocortisone during the night, before the alarm clock has had its say.

Cortisol is not meant to be a flat line

A healthy adrenal gland does not drip out one steady amount of cortisol all day. Cortisol is normally very low around midnight. It then starts to rise in the early hours—often from roughly 2–4 am—climbs towards a peak around waking, and gradually falls across the day. Smaller pulses sit on top of this broad daily rhythm.

This early-morning rise is not decorative physiology. It helps prepare circulation, metabolism, alertness and immune activity for the transition from sleep to wakefulness. In other words, the body starts opening the shop before you arrive.

In adrenal insufficiency, that overnight preparation may be absent. Immediate-release hydrocortisone taken after waking can replace cortisol, but only after the tablet has been swallowed and absorbed. This helps explain a familiar patient experience: “Once my morning tablets work, I improve—but getting to that point can feel like wading through treacle.”

The challenge is therefore more subtle than supplying enough hydrocortisone over 24 hours. The aim is to deliver enough at the right times, while avoiding too much exposure—especially late in the day, when excess cortisol may disturb sleep and, over time, contribute to weight gain, higher blood pressure, glucose intolerance and bone loss.

How Plenadren works: begin at waking, then taper

Plenadren is a dual-release tablet. Its outer coating releases hydrocortisone quickly after the morning dose; its inner core extends the release so that cortisol then declines through the day. It is usually taken once daily on waking, at least 30 minutes before food, and swallowed whole.

Compared with the same daily dose of immediate-release hydrocortisone given three times a day, Plenadren produces less late-afternoon and evening cortisol and about 20% lower total 24-hour cortisol exposure. That lower exposure may be part of its attraction: replacement should fill a deficiency, not quietly recreate Cushing’s syndrome by instalments.

In the pivotal 12-week crossover trial of 64 adults with primary adrenal insufficiency, Plenadren was associated with modest improvements compared with three-times-daily conventional hydrocortisone: mean weight was 0.7 kg lower, blood pressure fell by about 5.5/2.3 mmHg, and glucose measures improved, particularly in the small subgroup with diabetes. Other studies have reported improvements in some metabolic and quality-of-life outcomes, although the evidence is heterogeneous and not every study finds every benefit.

PLENADREN’S DESIGN QUESTION  How can we create a useful morning rise after the patient wakes, then reduce unnecessary cortisol exposure later in the day?

How Efmody works: prepare before waking

Efmody—called Chronocort during its clinical development—is a delayed- and extended-release hydrocortisone capsule. Most of the daily dose is taken at bedtime and the remainder in the morning. The evening capsule does not simply dump cortisol into the bloodstream at bedtime; its delayed release is designed to generate the rise several hours later, towards dawn.

This “toothbrush regimen”—last thing at night and first thing in the morning—is memorable for a useful reason. It aims to provide cortisol before waking rather than asking a person with very little cortisol to wake, remember a tablet, wait for absorption and only then begin the day.

Efmody was first developed for congenital adrenal hyperplasia (CAH), where the predawn cortisol gap has a second consequence. Without cortisol feedback, the pituitary releases more ACTH overnight; ACTH then pushes the adrenal glands to produce excessive androgen precursors. Covering the predawn hours can therefore both replace cortisol and calm this early-morning hormonal commotion.

Importantly, the UK indication changed in May 2026. Efmody is now approved for both adrenal insufficiency and CAH in adults and adolescents aged 12 years and over. Treatment remains specialist-led and individualised.

EFMODY’S DESIGN QUESTION  Can cortisol begin rising while the patient is still asleep, so that the body wakes to a more physiological hormonal morning?

Plenadren and Efmody at a glance

	Plenadren	Efmody
Active medicine	Hydrocortisone	Hydrocortisone
Formulation idea	Immediate-release coating plus extended-release core	Delayed- and extended-release granules inside a capsule
Usual rhythm	One dose on waking; cortisol rises after the dose and declines through daytime	Bedtime plus morning doses; the bedtime dose (2/3rd of total dose) aims to create the predawn rise
Waking cortisol	Usually low before the morning tablet	Designed to be present before waking
UK indications (2026)	Adrenal insufficiency in adults	Adrenal insufficiency and CAH in adults and adolescents aged 12+
Established evidence strength	Longer experience and several studies versus conventional replacement, including metabolic outcomes	Direct short-term comparison with Plenadren in primary adrenal insufficiency; CAH trials show better morning biochemical control
Practical attraction	Once-daily simplicity and lower later-day cortisol exposure	More physiological overnight-to-morning profile; may help morning fatigue and CAH biochemical control
Practical limitation	Cannot provide cortisol before the tablet is taken; fasting timing matters	Twice-daily routine; bedtime adherence matters; long-term comparative outcomes remain limited

Doses and timing are individualised. This table describes design principles, not a prescription.

The head-to-head test: what did CHAMPAIN find?

The most informative direct comparison is the CHAMPAIN study, published in 2026. It was randomised, double-blind and double-dummy: participants took matching placebos so that neither they nor the investigators knew which active schedule they were receiving. Fifty-eight adults with primary adrenal insufficiency entered the crossover study. Each person received four weeks of Efmody/Chronocort (15 mg at night and 10 mg in the morning) and four weeks of Plenadren (25 mg in the morning), in random order.

The biological difference was striking. At 7 am, median serum cortisol was 417 nmol/L with Efmody/Chronocort and 6 nmol/L with Plenadren. Among the 49 evaluable participants, 92% achieved the study’s physiological waking cortisol threshold with Efmody/Chronocort, compared with 4% with Plenadren.

Did patients actually feel better? Several measures said yes. Efmody/Chronocort improved the disease-specific AddiQoL score, the PROMIS fatigue score, the SF-36 physical component and EQ-5D-5L quality-of-life measure. However, the prespecified Multidimensional Assessment of Fatigue—the key secondary endpoint—was not significantly different in the main crossover analysis. A prespecified first-period analysis favoured Efmody/Chronocort, suggesting that benefit may have carried over after participants switched treatments.

This is a thoughtful and encouraging study because it compared the two formulations directly and blinded the treatments. It also has important boundaries: treatment periods lasted only four weeks; the study involved primary adrenal insufficiency rather than secondary adrenal insufficiency or CAH; there was no washout between periods; 49 participants were evaluable for the main analysis; and the study was funded by the manufacturer developing Efmody. The result supports the importance of waking cortisol—but cannot yet tell us whether one formulation prevents more adrenal crises, fractures, diabetes or cardiovascular disease over many years.

EVIDENCE, TRANSLATED  Efmody convincingly won the “cortisol present at waking” contest and improved several patient-reported outcomes in this short trial. The longer and harder contest—better lifetime health—has not yet been completed.

And what about congenital adrenal hyperplasia?

CAH adds another layer to the story. In the common 21-hydroxylase-deficient form, the adrenal gland cannot efficiently complete cortisol production. The pituitary notices the shortage and raises ACTH. The adrenal factory responds enthusiastically—but because one production line is blocked, more material is diverted towards androgen production.

Standard glucocorticoid treatment therefore has two jobs: replace missing cortisol and restrain ACTH-driven androgen excess. The awkward part is timing. The strongest ACTH and androgen rise often occurs in the early morning, when ordinary hydrocortisone taken the previous day has largely disappeared.

In a 122-person phase 3 study, Efmody did not meet its primary endpoint for the average 24-hour 17-hydroxyprogesterone change at six months. That sentence matters. So does the rest of the result: control was better at earlier visits and during the morning window; at six months, 91% receiving Efmody versus 71% on standard therapy had controlled 9 am 17-hydroxyprogesterone. During extension treatment, the median hydrocortisone dose eventually fell to 20 mg daily while biochemical control was maintained. Patient-reported menstrual restoration and pregnancies were observed, but those findings were exploratory rather than definitive fertility trials.

For a person with CAH, therefore, Efmody has a disease-specific rationale that Plenadren does not fully share: it targets the night-time ACTH drive. Plenadren may provide elegant daytime replacement, but a tablet taken after waking arrives after the predawn androgen surge has already been busy.

So which is better?

The honest answer is: better for which problem, in which person? Medicine becomes unhelpful when a population average is promoted to a personal destiny.

Plenadren may remain an attractive option when once-daily simplicity is a priority, when reducing late-day cortisol exposure is the main aim, or when a person is already stable and well on it. Its metabolic evidence is more mature than Efmody’s long-term head-to-head evidence, although much of that literature compares Plenadren with conventional hydrocortisone rather than with Efmody.

Efmody may be particularly attractive when mornings remain profoundly difficult despite sensible replacement, when recreating the predawn cortisol rise is a priority, or when CAH control—especially early-morning androgen excess—is problematic. The 2026 CHAMPAIN results provide direct support for improved waking cortisol and several short-term patient-reported outcomes in primary adrenal insufficiency.

Neither preparation reproduces every natural cortisol pulse, and neither removes the need for dose individualisation. Some patients may feel markedly better after switching; others may not. More physiological on a graph is valuable, but the person attached to the graph still gets the final vote.

Five questions worth discussing with your endocrinologist

·     Is my main difficulty before the morning dose, later in the day, or throughout the day?

·     Am I receiving too little cortisol at certain hours—or too much overall?

·     If I have CAH, are my morning 17-hydroxyprogesterone and androstenedione patterns adequately controlled?

·     Would once-daily simplicity or predawn coverage matter more for my routine and symptoms?

·     How will we judge a switch fairly—symptoms, blood pressure, weight, glucose, biochemical profiles and an agreed review period?

The safety rules do not change with cleverer packaging

Modified release does not make adrenal insufficiency crisis-proof. Both medicines are maintenance treatments, and every patient still needs an individual sick-day plan, a steroid emergency card or equivalent medical identification, access to emergency injectable hydrocortisone, and clear instructions for vomiting, diarrhoea, fever, injury and surgery.

During significant illness or stress, immediate-release or injected hydrocortisone may be required because the body needs extra cortisol quickly. Vomiting or severe diarrhoea can prevent oral medicine from being absorbed. Severe weakness, fainting, confusion, persistent vomiting or suspected adrenal crisis requires urgent emergency treatment—not an online comparison article and a cup of tea.

Do not stop hydrocortisone suddenly or switch formulation without specialist guidance. Equal milligram numbers do not guarantee identical exposure, and the timing and monitoring plan must change with the formulation.

The take-home message

Plenadren and Efmody represent two generations of the same idea: cortisol replacement should respect the clock.

Plenadren improves the daytime curve after a once-daily morning dose and may reduce later-day and total cortisol exposure compared with conventional tablets. Efmody begins the work overnight and, in the strongest direct comparison so far, restored waking cortisol and improved several measures of fatigue and quality of life over four weeks. In CAH, its predawn action also targets the ACTH-driven morning androgen surge.

The exciting lesson is not that one brand has defeated the other. It is that cortisol timing is clinically meaningful—and treatment can increasingly be matched to the part of the day in which a patient’s physiology is letting them down.

The best formulation is therefore not the one with the cleverest graph. It is the one that provides safe replacement, fits the diagnosis and daily routine, improves the outcomes that matter, and does so at the lowest appropriate glucocorticoid exposure.

PLEASE REMEMBER  This article is for education and cannot replace individual medical advice. Adrenal insufficiency and CAH require specialist supervision. Never alter or stop glucocorticoid treatment without an agreed plan.

Further reading

1. Prete A, et al. CHAMPAIN: Chronocort versus Plenadren in primary adrenal insufficiency. eClinicalMedicine. 2026;91:103714.

2. Steintorsdottir SD, et al. Extended-release hydrocortisone formulations—is there a clinically meaningful benefit? JCEM. 2025;110:e566–e573.

3. Johannsson G, et al. Improved cortisol exposure-time profile and outcome with once-daily dual-release hydrocortisone. JCEM. 2012;97:473–481.

4. Merke DP, et al. Modified-release hydrocortisone in congenital adrenal hyperplasia. JCEM. 2021;106:e2063–e2077.

5. UK Summary of Product Characteristics: Plenadren modified-release tablets.

6. Efmody product information (current European product information; includes AI and CAH indications).