Quercetin Supplements UK — Dihydrate, Phytosome & Bromelain Compared
Quercetin supplements, explained.
What quercetin actually is, how the dihydrate and phytosome preparations differ, why it is so often sold alongside bromelain — and why the milligram figures on the front of the bottle are not comparable between them.
Quercetin supplements UK — summary
Quercetin is a flavonol, a subclass of flavonoid, found naturally in onions, apples, capers, berries and green tea. As a supplement it is sold in several preparations. Quercetin dihydrate is the standard crystalline form and is poorly soluble in water. Quercetin phytosome binds quercetin to phospholipids, a delivery approach used to improve absorption relative to standard quercetin. Quercetin is also frequently combined with bromelain, a group of proteolytic enzymes from pineapple stem. The Vitality Supplements UK range includes three quercetin formulas: Quercetin Dihydrate 250mg per serving at GBP 16.99; Quercetin Phytosome 500mg per serving at GBP 14.99; and Bromelain 500mg plus Quercetin 250mg at GBP 14.99. All three use vegan capsules, are manufactured in the United Kingdom and tested every batch by an ISO/IEC 17025-accredited laboratory, with a Certificate of Analysis available on request. Milligram figures are not directly comparable across preparations because a phytosome complex includes the phospholipid carrier in its stated weight. There are no authorised UK or EU health claims on quercetin.
What quercetin is.
Quercetin is a flavonol — one subclass of the flavonoids, the large family of plant pigments that give fruit and vegetables much of their colour. It occurs naturally in onions (particularly red onion skin), apples, capers, berries, kale and green tea, so most people already take in small amounts through diet.
In supplement form it is isolated and concentrated, typically from Sophora japonica (Japanese pagoda tree) flower buds, which are unusually rich in it. That is why a capsule can carry a few hundred milligrams where a portion of onion carries a few tens of milligrams.
The practical problem with quercetin is solubility. In its standard crystalline form it dissolves poorly in water, and that has shaped how the supplement industry sells it — nearly every variation you will see on a label is an attempt to address that one property, either by changing the preparation or by pairing it with something else.
Understanding that is most of what you need to compare products sensibly, because it explains why a 500mg product and a 250mg product are not simply "double" and "half".
Dihydrate and phytosome.
Two preparations account for most of what is sold in the UK. They are the same molecule, delivered differently.
Quercetin dihydrate
The standard form — quercetin with two water molecules bound into its crystal structure. It is the most widely used, the least expensive to produce and the form most published research has used. The stated milligram figure is quercetin itself, which makes it the easiest to reason about: 250mg of quercetin dihydrate is 250mg of quercetin.
Quercetin phytosome
A phytosome binds the compound to phospholipids — typically sunflower-derived lecithin. The phospholipid acts as a carrier, and phytosome formats are used across the supplement industry for poorly-soluble plant compounds, including berberine and curcumin, for the same reason.
Here is the part people misread. The stated weight of a phytosome product usually includes the phospholipid carrier, not just the quercetin. So a 500mg phytosome complex does not contain 500mg of quercetin — it contains a smaller quercetin fraction bound to a carrier. That is not a criticism of the format; it is simply why you cannot line the numbers up directly against a dihydrate product and conclude one is twice the other.
The same logic applies elsewhere in our range — it is the reason berberine's three forms carry very different milligram figures.
Why bromelain turns up alongside it.
Bromelain is a group of proteolytic (protein-digesting) enzymes extracted from pineapple stem. It is measured in GDU or FIP activity units rather than by weight alone, because what matters is enzymatic activity.
Quercetin and bromelain have been sold together for decades, and the pairing is now conventional enough that many people looking for one expect to find the other on the label. If you are comparing products, the thing worth checking is simply how much quercetin is in the combination product — in a two-ingredient formula the quercetin dose is usually lower than in a single-ingredient one, because the capsule has to accommodate both.
Whether you want the pairing or the single ingredient is a matter of preference. A single-ingredient product lets you control the quercetin dose precisely; a combination is simpler if you wanted both anyway.
The three formulas, compared.
All three are vegan capsules, UK manufactured and batch-tested by an ISO/IEC 17025-accredited laboratory. The differences are preparation, dose and whether bromelain is included.
| Formula | Preparation | Per serving | Best suited to | Price | Buy |
|---|---|---|---|---|---|
| Quercetin Dihydrate★ Clearest dose | Standard crystalline quercetin | 250mg quercetin | Knowing exactly how much quercetin you are taking | £16.99 | |
| Quercetin Phytosome | Quercetin bound to phospholipids | 500mg phytosome complex | Preferring a phytosome delivery format | £14.99 | |
| Bromelain + Quercetin | Standard quercetin with pineapple enzymes | 500mg bromelain · 250mg quercetin | Wanting both ingredients in one capsule | £14.99 |
The 500mg figure on the phytosome product refers to the complex, which includes the phospholipid carrier — it is not 500mg of quercetin. Do not read the three numbers as directly comparable.
What to check on any quercetin product.
Neutral, verifiable things worth checking on any brand, not just ours.
The terms, defined.
Quercetin questions.
Written by the Vitality Supplements Editorial Team. We make the products described here, and we say so plainly. This guide is written to explain how quercetin preparations differ so you can compare any brand's label, not only ours — the buying checklist above applies regardless of who you buy from. We describe composition, preparation and labelling only. There are no authorised UK or EU health claims on quercetin, so we make none. See our editorial standards.
Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. If you are pregnant, breastfeeding, taking medication or under medical care, consult a healthcare professional before use. This page is general information, not medical advice, and is not intended to diagnose, treat or prevent any condition. There are no authorised UK or EU health claims on quercetin or bromelain, and no medicinal or disease claims are made here. Prices correct at the time of publication; live pricing is shown on each product page. Every Vitality batch is independently tested by an ISO/IEC 17025-accredited laboratory. UK manufactured. See our full disclaimer.