An Important Note on Dose and Medication Interactions
This product provides 500mg of quercetin per capsule, with the recommended 2-capsule serving delivering 1000mg daily. As covered in more detail in our complete quercetin guide, it’s worth knowing that clinical trials establishing quercetin’s safety profile generally used up to 500mg twice daily (1000mg total) as the upper studied range — this product’s standard recommended dose sits right at that upper limit rather than a more conservative middle-ground amount.
The most important thing to know about quercetin, missing from this product’s description entirely: it genuinely inhibits several liver enzymes (CYP3A4, CYP2D6, CYP2C19, and CYP1A2) involved in metabolising a wide range of common medications. This isn’t theoretical — there’s a documented clinical case of a patient on stable warfarin therapy experiencing a significantly elevated INR after starting quercetin. Medications affected by these same pathways include certain antidepressants (such as paroxetine and venlafaxine), some heart and blood pressure medications (including flecainide and metoprolol), tamoxifen, and quinolone antibiotics, among others. If you take any regular prescription medication, it’s genuinely worth checking with your GP or pharmacist before starting quercetin, rather than assuming a “completely natural” product is automatically compatible.
We’d also gently correct the claim that quercetin offers “more potent antioxidant benefits than traditional vitamin C, vitamin E, or beta carotene” — this kind of direct comparative claim isn’t something we could independently verify, and different antioxidants generally work through different mechanisms rather than existing on one single “more potent” scale.
Cyclosporine specifically should not be combined with quercetin without direct medical supervision. If you have kidney problems, quercetin is worth discussing with your GP first, and safety data during pregnancy and breastfeeding is limited, so it’s best avoided without medical guidance.
Vegan, non-GMO, free from magnesium stearate, lactose, and common allergens, manufactured to GMP standards in the UK. Take two capsules daily with a full glass of water, preferably with a meal. Not suitable for under-18s. Speak to your GP or pharmacist before starting if you take any regular prescription medication, have kidney problems, are pregnant, or are breastfeeding.
The Research Behind This Product
Energy & Vitality
Quercetin Supplements: What UK Research Actually Shows
Quercetin is one of the most widely sold antioxidant supplements in the UK, but it's also one of the few with genuine, well-documented interactions with common prescription medication. Here's what UK-relevant research actually supports, and the safety point most product listings leave out entirely.
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