Supplements and Tadalafil.
Tadalafil, sold under the brand names Cialis, Adcirca, is classified under "drugs for genitourinary disorders" in the BNF.
Tadalafil (UK brand names Cialis, Adcirca) sits at NHSBSA prescribing rank 143 in the 2024/25 PCA statistics. The BNF classifies it under "drugs for genitourinary disorders". This means it sits outside the high-volume therapeutic classes (statins, PPIs, ACE inhibitors, SSRIs) where supplement-interaction surfaces are densely studied, and the published evidence base for specific supplement pairs is correspondingly thinner. Where interactions are documented in the Distil database, they are listed below with their clinical-reference citation; where pairs have not been explicitly assessed, the missing-item form at the bottom of the page routes them into our next curation pass. Anyone combining Tadalafil with a regular supplement stack benefits from explicit GP or pharmacist awareness rather than assuming no interaction exists by default.
Below are the 2 documented pairs we have explicitly assessed against Tadalafil in the Distil database: 2 amber. The pairs cluster around 1 mechanism: Additive vasodilation. 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
Additive vasodilation
Tadalafil and beetroot both increase nitric-oxide-driven vasodilation, by different routes. Prescription organic nitrate medications (GTN spray, isosorbide) are strictly contraindicated with tadalafil because of severe blood pressure drops. Beetroot acts through the same downstream nitric oxide pathway but produces much lower nitric oxide levels than prescription nitrates. The theoretical risk is additive vasodilation and symptomatic low blood pressure. Tell your GP if you take both.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
L-citrulline raises nitric oxide, which widens blood vessels, and tadalafil works on the same nitric oxide pathway. Combining them could add up to a larger drop in blood pressure, so watch for dizziness, flushing, or faintness. Tadalafil lasts much longer than sildenafil, so the window where this matters is wider. Tell your GP if you take both.
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.
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 methodologyWant this checked across everything you take?
This page checks the pairs you enter. The personalised Distil report goes further:
- the same graded, cited interaction check across your whole stack, not just the pairs you thought to type in
- where your current routine may be leaving you short of your goals
- the evidence-backed compounds worth adding, and the ones worth dropping
It's a paid report: £79, or £49 for the first 25 customers. The interactions check is one section of it, and you can read a real one in full before you buy.
See a real sample reportSomething missing?
If a supplement or medication you take isn't in our autocomplete, tell us. We go through what people flag every week and add what's missing.