Supplements and Dapagliflozin.
Dapagliflozin, sold under the brand name Forxiga, is a sodium-glucose cotransporter 2 (SGLT2) inhibitor: it lowers blood glucose by increasing urinary glucose excretion.
Dapagliflozin is an SGLT2 inhibitor. The full name is sodium glucose cotransporter 2. The class lowers blood glucose by increasing urinary glucose excretion. It also carries a separate cardiovascular and renal benefit shown in DAPA-HF, EMPA-REG, and the CKD trials, leading to expanded indication in heart failure and CKD even without diabetes. The supplement surface is small because SGLT2 inhibitors are minimally CYP metabolised. The clinically important issues are urinary tract and genital fungal infections (since glucose in the urine creates favourable conditions), volume depletion in heat or illness (the diuretic effect adds to dehydration risk), and the rare diabetic ketoacidosis presentation including the unusual "euglycaemic" form. Cranberry supplementation often comes up for UTI prevention. The Cochrane evidence supports modest efficacy in recurrent UTI in women. Magnesium status warrants attention given the modest urinary magnesium loss that these inhibitors produce.
Below are the 4 documented pairs we have explicitly assessed against Dapagliflozin in the Distil database: 4 amber. The pairs cluster around 2 mechanisms: Reduced glucose control and Additive glucose 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
Reduced glucose control
Melatonin can blunt the body's insulin response and raise blood sugar after eating, which works against the blood-sugar control that dapagliflozin is helping with. The effect is strongest when melatonin and food are taken close together, so if you take dapagliflozin it is best to keep melatonin well away from your evening meal and to mention it to your prescriber if your blood sugar is being monitored.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive glucose lowering
Berberine lowers blood sugar, and dapagliflozin does too. The combination is usually well tolerated because dapagliflozin rarely causes low blood sugar on its own, but it is still worth monitoring your glucose when you start berberine and letting your GP know.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Garlic supplements may lower blood sugar a little on their own. Dapagliflozin also lowers blood sugar but rarely pushes it too low on its own, so the combination is generally manageable. Monitor your glucose when you start a garlic supplement or change the dose.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Pine bark extract (pycnogenol) may lower blood sugar a little on its own. Dapagliflozin also lowers blood sugar but rarely pushes it too low on its own, so the combination is generally manageable. Monitor your glucose when you start pine bark extract or change the dose.
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.
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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.
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