Supplements and Bisoprolol.
Bisoprolol, sold under the brand names Cardicor, Emcor, is a beta-blocker: it reduces heart rate and cardiac output by antagonising beta-adrenergic receptors.
Bisoprolol is a beta-blocker selective for the beta-1 receptor, and the most prescribed agent in this class in England. The drug slows heart rate. Uses are hypertension, stable angina, and at lower doses heart failure with reduced ejection fraction. The selectivity for beta-1 over beta-2 is relative, not absolute, so the asthma caution carries: bronchospasm risk rises as the dose climbs and the drug starts to touch airway receptors as well. Two cardiac interactions are worth flagging on the supplement side. The first is additive bradycardia, where CoQ10's effect is small and clinically minor while vagally active compounds matter more. The second is additive hypotension, where beetroot, hibiscus, and garlic stack on the BP side. Bisoprolol is not strongly CYP metabolised, so the CYP interactions are quieter than with statins or SSRIs. Watch in the early weeks for a resting heart rate below 50, or symptomatic dizziness on standing. Either warrants a GP review of dose rather than supplement adjustment.
Below are the 7 documented pairs we have explicitly assessed against Bisoprolol in the Distil database: 7 amber. The pairs cluster around 1 mechanism: 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 is assessed against PubMed-indexed evidence.
Additive blood-pressure lowering
Amber Does Beetroot Extract interact with ?
Beetroot lowers blood pressure through the nitric oxide pathway, and bisoprolol lowers blood pressure through beta-1 receptor blockade. Used together, the combined blood-pressure effect is mild but real. Watch for dizziness on standing, especially in the first two weeks. If symptoms appear, tell your GP.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does Garlic Extract interact with ?
Garlic supplements mildly lower blood pressure, and bisoprolol lowers it too. The combined effect is small but real. Watch for dizziness on standing in the first couple of weeks and tell your GP if it happens.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does Hibiscus Extract interact with ?
Hibiscus tends to lower blood pressure on its own, and bisoprolol is a beta blocker that lowers it too. Taken together the blood-pressure effects may stack, so watch for dizziness on standing, especially in the first couple of weeks. If symptoms appear, tell your GP.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Melatonin interact with ?
Taken at night, melatonin can modestly lower blood pressure during sleep. Combined with a blood-pressure medicine like bisoprolol this may add up to a slightly larger drop than the medicine alone. There is also a second point worth knowing: beta-blockers such as bisoprolol can suppress your own natural melatonin, so some people taking them sleep better when melatonin is added. Either way, if you notice dizziness, 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.
Amber Does Pine Bark Extract interact with ?
Pine bark extract (pycnogenol) mildly lowers blood pressure, and bisoprolol lowers it too. The combined effect is small but real. Watch for dizziness on standing in the first couple of weeks and tell your GP if it happens.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Spirulina interact with ?
Spirulina has a mild blood-pressure-lowering effect of its own, shown in human trials. Bisoprolol lowers blood pressure mainly by slowing the heart and easing its workload. Used together, the combined effect tends to be a little larger than the medicine alone. Watch for dizziness on standing in the first couple of weeks, and tell your GP if it happens so your dose can be reviewed.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does Taurine interact with ?
Taurine tends to lower blood pressure and heart rate a little on its own, and bisoprolol is a beta blocker that also lowers both. Taken together the effects may stack, so watch for dizziness on standing or feeling unusually tired, especially in the first couple of weeks. The added effect tends to be modest. If symptoms appear, tell your GP.
Evidence: Limited human data, based on case reports and a known mechanism.
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.
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- the same graded, cited interaction check across your whole stack, not just the pairs you thought to type in
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- the evidence-graded compounds worth adding, and the ones worth dropping
It's a paid report: £79, or £49 founder pricing while we earn our first reviews. The interactions check is one section of it, and you can read a real one in full before you decide.
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