Supplements and Spironolactone.
Spironolactone, sold under the brand name Aldactone, is a potassium-sparing diuretic: it blocks aldosterone or epithelial sodium channels, conserving potassium.
Spironolactone is a diuretic that spares potassium. The class includes spironolactone and eplerenone (mineralocorticoid receptor antagonists), and amiloride and triamterene (epithelial sodium channel blockers). UK prescribing centres on spironolactone for heart failure, resistant hypertension, primary aldosteronism, and (outside the licence at low doses) acne. The supplement surface centres on potassium. Anything that adds to potassium load (foods rich in potassium at high intake, salt substitutes containing potassium chloride, magnesium at high doses with associated potassium effects) stacks on top and can drive hyperkalaemia, particularly in patients with reduced renal function. Real liquorice opposes the BP lowering effect by retaining sodium, driven by glycyrrhizin rather than by aldosterone, which reads low. Spironolactone's androgen-blocking activity at higher doses interacts notionally with the same property in herbal supplements (saw palmetto). But the clinical magnitude is small.
Below are the 2 documented pairs we have explicitly assessed against Spironolactone in the Distil database: 1 red and 1 amber. The pairs cluster around 2 mechanisms: Additive hyperkalaemia (raised potassium) and Additive blood-pressure lowering. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement into our next curation pass.
Documented interactions
Last reviewed 14 June 2026. Each interaction below lists the evidence its assessment drew on: some rest on studies of the exact pair, others on mechanism evidence, where a citation may support one part of the reasoning rather than the exact combination. The evidence line on each entry says which.
Additive hyperkalaemia (raised potassium)
Red Does Potassium interact with ?
Spironolactone is a potassium-sparing diuretic, which means it makes the body hold on to potassium. Adding a potassium supplement on top can push potassium to a dangerous level and affect the heart rhythm. This is one of the higher-risk combinations. Do not take potassium with spironolactone unless your specialist has advised it and is monitoring your blood potassium closely.
Evidence: Well established across multiple human studies or interaction references.
Additive blood-pressure lowering
Amber Does Melatonin interact with ?
Taken at night, melatonin can modestly lower blood pressure during sleep. Combined with a blood-pressure medicine like spironolactone this may add up to a slightly larger drop than the medicine alone. This is usually mild and often welcome, but if you notice dizziness or lightheadedness, check your blood pressure and mention it to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.
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How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologyA full supplement review, built around you, not a generic stack.
The free checker answers one interaction question at a time. A Distil report reviews the bigger picture: your goals, diet, medications, current supplements and any blood results you provide, then shows what appears worth keeping, changing, adding or leaving out.
- what your diet already covers, so you are not adding a capsule for something food is already handling
- which evidence-graded compounds are worth considering for your goals, and which were considered but left out
- what to keep, change or stop from what you already take, plus the order to introduce anything new
- how your medications and complete supplement stack fit together, with daily timing and a clear point for reassessment
The interaction check is one section of the full report. You also get the reasoning behind each recommendation and the evidence references used.
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