Blood pressure is often described as a problem of salt, stress, age, or genetics. Sometimes that is true. But in a meaningful number of people, especially those with hard-to-control hypertension, a specific hormone is part of the story. That hormone is aldosterone.
Aldosterone helps the body decide how much sodium to keep, how much potassium to lose, and how much fluid stays in circulation. When that system is working well, it helps maintain blood pressure and supports basic survival. When it becomes overactive, the same hormone can quietly push blood pressure upward, strain the heart and kidneys, and create a pattern that is more treatable than many people realize.
This is why aldosterone matters far beyond a lab result. If it is too high, the issue is not just the number on the cuff. It is the kind of hypertension it may signal, the risks that come with it, and the opportunity to find a cause that can often be targeted with specific treatment.
Quick Facts
- Aldosterone helps regulate sodium, potassium, fluid balance, and blood pressure.
- Excess aldosterone can drive hypertension, low potassium, and higher heart and kidney risk even when symptoms are subtle.
- Many people with high aldosterone have normal potassium, so a normal potassium level does not rule it out.
- Screening is most useful in resistant hypertension, hypertension with low potassium, early-onset hypertension, or an adrenal nodule.
- The usual starting test is an aldosterone-to-renin ratio, and medication changes for testing should be guided by a clinician.
Table of Contents
- What Aldosterone Normally Does
- How Excess Aldosterone Raises Blood Pressure
- When to Suspect It Is Too High
- What Causes High Aldosterone
- How Doctors Test for It
- Treatment and What to Do Next
What Aldosterone Normally Does
Aldosterone is a mineralocorticoid hormone made by the adrenal glands, which sit on top of the kidneys. Its main job is practical and narrow: it helps the kidneys hold on to sodium and water while promoting the loss of potassium and hydrogen ions. That balance matters because sodium helps determine how much fluid stays in the bloodstream, and that directly affects blood pressure.
In ordinary daily life, aldosterone rises and falls in response to the body’s needs. If blood volume drops, if sodium intake is low, or if potassium rises, the renin-angiotensin-aldosterone system becomes more active. The kidneys release renin, a chain reaction follows, and aldosterone increases. The kidneys then reabsorb more sodium, more water follows, and circulation is supported. In an ancestral world of scarce salt and frequent dehydration, this was a survival system. In a modern world of abundant sodium, that same system can become harmful when it is overactive.
Aldosterone’s effects are concentrated in the distal nephron, the part of the kidney that fine-tunes what the body keeps and what it discards. That is why its influence is so tightly tied to fluid volume, blood pressure, and sodium and potassium balance. When aldosterone is working as it should, it helps the body stay steady. When it is being produced in excess, that fine-tuning becomes chronic overcorrection.
This hormone is easy to overlook because it does not create a distinctive feeling of its own. People do not usually say they “feel aldosterone.” What they feel, if anything, is the consequence: higher blood pressure, low potassium symptoms, or vague fatigue. Some feel nothing until a screening test is done for resistant hypertension.
It also helps to understand that aldosterone is not the same as cortisol, even though both come from the adrenal glands. Cortisol is better known because of its links to stress, immune regulation, and metabolism. Aldosterone is quieter, but in the setting of hypertension it can be just as important. Its abnormal excess is usually discussed under the term primary aldosteronism, meaning the adrenal gland is producing aldosterone more autonomously than it should.
The key point is that aldosterone is not a “bad” hormone. It is essential. Trouble starts when the signal is too strong, too persistent, or disconnected from the body’s actual needs. When that happens, blood pressure can rise for hormonal reasons rather than from lifestyle alone, and the right diagnosis can change the entire treatment approach.
How Excess Aldosterone Raises Blood Pressure
When aldosterone is too high, the body retains more sodium than it should. Water follows sodium, blood volume expands, and blood pressure rises. That is the central mechanism, but it is not the only one. Aldosterone also seems to contribute to inflammation, vascular stiffness, heart remodeling, and kidney strain in ways that are not fully explained by blood pressure alone. In other words, excess aldosterone is not just a volume problem. It is a tissue-level problem too.
This matters because two people can have the same blood pressure reading and not carry the same hormonal risk. A person with aldosterone-driven hypertension may face greater chances of atrial fibrillation, heart enlargement, stroke, kidney damage, and metabolic complications than someone with essential hypertension alone. That is one reason early recognition matters.
The classical picture of high aldosterone is hypertension plus low potassium. That picture still exists, but it is not the rule. Many people with primary aldosteronism have normal potassium levels, especially early on. Their clue is not dramatic weakness or paralysis. It is a blood pressure pattern that is harder to control than expected or that shows up early, severely, or alongside an adrenal nodule.
The blood pressure pattern can vary:
- It may be resistant hypertension, meaning blood pressure stays high despite three medications.
- It may be hypertension that improves only partially with standard therapy.
- It may be hypertension with repeated low potassium, especially after a thiazide diuretic.
- It may be hypertension that appears unusually early in adult life.
- It may be hypertension with sleep apnea, atrial fibrillation, or a strong family history of early stroke.
Excess aldosterone also changes how the kidneys handle potassium. Potassium is pushed out into the urine, which can produce muscle weakness, cramps, palpitations, constipation, fatigue, frequent urination, or increased thirst when the level drops enough. Severe potassium depletion can be dangerous, but mild abnormalities are easier to miss.
Another subtle point is that aldosterone-related blood pressure can coexist with common metabolic issues. A person may also have abdominal weight gain, insulin resistance, or features that overlap with metabolic syndrome. That overlap can make hormonal hypertension look ordinary at first glance. It is one reason the condition is often under-recognized.
The practical takeaway is that excess aldosterone should be thought of as a specific form of secondary hypertension. It is not rare enough to ignore, and it is not exotic medicine. It is a real, treatable cause of high blood pressure that can be present even when potassium is normal and symptoms are vague. Recognizing that pattern is the first step toward treatment that targets the cause rather than only the blood pressure number.
When to Suspect It Is Too High
High aldosterone is worth suspecting when the blood pressure story does not fit the usual script. Many people with primary aldosteronism do not look dramatically ill. They may simply have hypertension that seems out of proportion to their age, fitness level, or treatment plan.
The strongest clues include:
- Blood pressure that remains above target despite three medications, especially if one is a diuretic
- Hypertension plus low potassium, whether spontaneous or triggered by a thiazide
- Hypertension diagnosed at a young age
- Hypertension in someone with an adrenal incidentaloma
- A personal history of atrial fibrillation, sleep apnea, or early cardiovascular disease along with hypertension
- A family history of early-onset hypertension or stroke
Symptoms can be surprisingly nonspecific. Some people have headaches, fatigue, muscle weakness, muscle cramps, palpitations, numbness, constipation, frequent urination, or excessive thirst. Others have no symptoms apart from an elevated blood pressure reading. That is why high aldosterone is often found through pattern recognition rather than through one classic symptom.
Low potassium deserves special attention, but it should not be overused as a screening rule. Normal potassium does not rule out primary aldosteronism. In fact, many cases are missed because clinicians and patients still assume the diagnosis should look dramatic. A quieter presentation is common.
It also helps to think about what else can mimic this picture. Resistant hypertension can have several endocrine and renal causes. Kidney disease, renal artery narrowing, obstructive sleep apnea, medication effects, excess alcohol, and other hormone disorders can all contribute. In rare cases, an adrenal-catecholamine condition such as pheochromocytoma may be part of the differential when blood pressure is severe, episodic, or accompanied by pounding headaches, sweating, and racing heartbeats.
People sometimes ask whether sodium craving points to high aldosterone. Not reliably. Aldosterone is more about how the body handles sodium than about whether you consciously crave it. The more useful question is whether blood pressure, potassium, kidney function, and medication response suggest the hormone is active in the wrong way.
Screening is especially worthwhile when treatment decisions could change. If someone is labeled as having “difficult essential hypertension” but actually has primary aldosteronism, that can open the door to targeted medication or, in some cases, curative surgery. That is a very different outcome from endlessly adding standard blood pressure drugs without asking why the pressure is high in the first place.
The broader message is simple: suspect excess aldosterone when hypertension seems unusually severe, unusually stubborn, or biologically mismatched to the person sitting in front of you. That is often where the diagnosis begins.
What Causes High Aldosterone
High aldosterone is not one disease. It is a finding with different causes, and the cause determines the treatment path.
The first major distinction is between primary and secondary hyperaldosteronism.
Primary aldosteronism means the adrenal glands are producing aldosterone too autonomously. Renin is usually low because the body senses that there is already too much volume and does not need to stimulate the system further. This is the form most closely linked to endocrine hypertension and the form clinicians usually mean when they discuss aldosterone as a missed cause of high blood pressure.
Common causes of primary aldosteronism include:
- A unilateral aldosterone-producing adenoma
- Unilateral adrenal hyperplasia
- Bilateral adrenal hyperplasia
- Less commonly, familial forms
This distinction matters because unilateral disease may be treated surgically, while bilateral disease is usually treated with medication.
Secondary hyperaldosteronism is different. In that setting, the body is driving aldosterone upward for a reason, usually through higher renin. Causes include reduced blood flow to the kidneys, aggressive diuretic use, dehydration, heart failure, cirrhosis, nephrotic syndrome, and sometimes pregnancy-related physiology. Here the adrenal glands are responding to a signal rather than acting independently.
That is why paired testing matters. An aldosterone level alone cannot tell the full story. Clinicians look at aldosterone together with renin. A high aldosterone with suppressed renin points toward primary aldosteronism. A high aldosterone with high renin points more toward a secondary driver.
People also wonder whether stress causes high aldosterone. Acute illness and body stress can affect the renin-angiotensin-aldosterone system, but chronic primary aldosteronism is not simply the result of being stressed. It is a hormonal disorder with structural or functional adrenal causes. This distinction is important because it keeps people from chasing vague stress explanations when a specific diagnosis deserves attention.
Another helpful contrast is with other adrenal disorders. The adrenal glands make several hormones, and symptoms can overlap. For example, weakness and blood pressure changes can also appear in adrenal insufficiency, but that condition reflects inadequate adrenal hormone production rather than excess aldosterone production. The direction of the problem, the potassium pattern, and the treatment are entirely different.
In practice, the most clinically important question is not “Is aldosterone high?” in isolation. It is “Why is it high, and is the secretion autonomous?” Once that is clear, treatment becomes much more rational. Some people need a full endocrine workup for suspected primary aldosteronism. Others need their kidney circulation, medications, or volume status assessed because the aldosterone rise is secondary.
Understanding the cause is what turns a lab abnormality into a useful diagnosis.
How Doctors Test for It
Testing for excess aldosterone usually starts with a screening blood test called the aldosterone-to-renin ratio, often shortened to ARR. This is the most common entry point because it captures the basic pattern clinicians care about: aldosterone that is inappropriately high while renin is suppressed.
The test sounds simple, but preparation matters. Renin and aldosterone are influenced by posture, time of day, potassium level, sodium intake, and many blood pressure medications. That is why testing is often done in the morning after the patient has been sitting quietly for a short time. Low potassium is usually corrected first, and patients are often asked not to restrict salt before the screening test unless they have been given different instructions for medical reasons.
Medication effects are a major reason interpretation can be tricky. Drugs that may distort the result include:
- Mineralocorticoid receptor antagonists such as spironolactone and eplerenone
- Diuretics
- ACE inhibitors
- ARBs
- Beta-blockers
- Some centrally acting agents
This does not mean everyone must stop every medication. In many real-world cases that is unsafe or impractical. Instead, clinicians may interpret the pattern in context, substitute less interfering drugs when appropriate, or repeat testing under better conditions. This is one reason aldosterone testing should not be DIY medicine. It sits squarely within the kind of careful interpretation covered in hormone testing basics.
If the screening test is positive, the next step may be confirmatory testing. Depending on the clinical picture, this can include saline infusion testing, oral sodium loading, fludrocortisone suppression, or a captopril challenge. The goal is to show that aldosterone remains inappropriately active when it should be suppressible. In some clearly classic cases, confirmatory testing may be skipped.
After biochemical confirmation, imaging enters the picture. Adrenal CT is commonly used to look for nodules and to rule out other adrenal pathology. But imaging alone is often not enough to decide whether one adrenal gland or both are responsible. That is where adrenal vein sampling comes in. This specialized procedure measures hormone output from each adrenal gland and is especially important when surgery is being considered.
A typical testing sequence looks like this:
- Identify who should be screened.
- Measure aldosterone and renin under suitable conditions.
- Confirm autonomous secretion when needed.
- Use imaging and, when appropriate, adrenal vein sampling to determine laterality.
This can sound like a lot, but it answers the most important clinical question: is the excess aldosterone coming from one side and potentially curable with surgery, or from both sides and better treated medically? That answer shapes the entire next step.
Treatment and What to Do Next
Once excess aldosterone is confirmed, treatment becomes much more targeted. The main goals are to lower blood pressure, correct potassium abnormalities, reduce long-term cardiovascular and kidney risk, and match the treatment to the source of hormone excess.
If the excess comes from one adrenal gland, usually because of an aldosterone-producing adenoma or unilateral hyperplasia, surgery may be the preferred option. Laparoscopic adrenalectomy can normalize potassium quickly and improve blood pressure substantially. Some people come off several medications. Others still need blood pressure treatment afterward, especially if hypertension has been present for years, but they often need fewer medications and have less hormonal injury going forward.
If the excess is bilateral, or if surgery is not desired or not appropriate, medical treatment is usually the path forward. The standard therapy is a mineralocorticoid receptor antagonist:
- Spironolactone is often used first because it is widely available and effective.
- Eplerenone is an alternative when spironolactone causes side effects.
- Amiloride may be used in selected situations, particularly when mineralocorticoid receptor antagonists are not tolerated or need support.
Treatment does not stop at prescribing a pill. Follow-up is essential. Blood pressure, potassium, and kidney function need monitoring, especially when therapy starts or doses change. Renin may also be followed in specialist care because persistently suppressed renin can suggest that aldosterone blockade is still incomplete.
Lifestyle still matters, but it is supportive rather than curative on its own. Sodium reduction can help because a high-salt diet amplifies the harmful effects of excess aldosterone. Patients are often surprised to learn that diet becomes more effective once the hormonal driver is also being treated. Before that, the body may be working against them.
A sensible next-step plan after diagnosis usually includes:
- Clarify whether the source is unilateral or bilateral.
- Begin targeted therapy rather than relying only on generic blood pressure escalation.
- Recheck potassium, creatinine, and blood pressure within the first few weeks of treatment changes.
- Review home blood pressure readings rather than relying on clinic readings alone.
- Arrange endocrine or hypertension-specialist follow-up when the case is complex.
You should seek urgent care for very high blood pressure with chest pain, severe headache, confusion, weakness, shortness of breath, or signs of severe potassium depletion such as marked muscle weakness, palpitations, or fainting. Those are not routine follow-up symptoms.
For non-urgent cases, specialist input is especially valuable when testing is difficult to interpret, imaging and lab results do not match, or surgery is under consideration. That is often the point where readers benefit from knowing when specialist evaluation makes sense.
The most encouraging part of this diagnosis is that it gives high blood pressure a more precise explanation. In a field where many people are told to simply “manage” hypertension forever, aldosterone excess offers something better: a cause that can often be specifically treated.
References
- Primary Aldosteronism: An Endocrine Society Clinical Practice Guideline 2025 (Guideline)
- Clinical Management of Primary Aldosteronism: An Update 2024 (Review)
- 2023 Korean Endocrine Society Consensus Guidelines for the Diagnosis and Management of Primary Aldosteronism 2023 (Guideline)
- Diagnosis and management of primary hyperaldosteronism in patients with hypertension: a practical approach endorsed by the British and Irish Hypertension Society 2024 (Consensus)
- Primary Aldosteronism: State-of-the-Art Review 2022 (Review)
Disclaimer
This article is for educational purposes only and is not a substitute for medical advice, diagnosis, or treatment. Aldosterone and renin testing can be affected by medications, sodium intake, potassium levels, posture, and kidney or heart conditions, so results should be interpreted by a qualified clinician. Seek prompt medical care for severe hypertension, chest pain, shortness of breath, confusion, fainting, or severe muscle weakness, especially if low potassium is suspected.
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