Life Extension's Bio-Quercetin is the category's paradox: a highly-absorbable galactomannan phytosome that leans entirely on a 62x bioavailability claim to justify a tiny ~15 mg dose. At ~$8 it's the cheapest entry and pairs naturally with the brand's vitamin C. But even a big absorption multiple can't turn 15 mg into the 500-1000 mg used in trials, so it functions as a supporting micro-dose, not a primary quercetin.
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Read the complete Quercetin guide →A real phytosome format with a strong absorption claim, but the 62x figure is manufacturer-derived and applied to a dose so small that even large multiples yield little absolute quercetin.
~15 mg is a tiny fraction of the 500-1000 mg used in human trials. Even a generous absorption multiple can't close that gap, the biggest weakness here.
Non-GMO, gluten-free, vegetarian from a brand with a solid QC reputation. Reasonable, though the marketing multiplier deserves skepticism.
At 15 mg it's extremely gentle and easy to add to any stack, with essentially no tolerability concerns.
~$8 is cheap in absolute terms but expensive per milligram of quercetin delivered; you'd need many caps to approach studied doses.
“62x bioavailability makes 15 mg equivalent to a large standard dose”
The 62x figure is a manufacturer PK comparison; even taken at face value, 15 mg x an absorption multiple does not replicate the plasma exposure of 500-1000 mg studied doses, and the equivalence is marketing math.
“The phytosome format genuinely improves absorption”
Phytosome delivery does improve quercetin uptake in principle (Riva 2019, PMID 30328058), but Life Extension's specific 62x multiple isn't independently verified and is applied to a very small base dose.
Bio-Quercetin is designed to slot alongside Life Extension's vitamin C and other formulas. As a component it's fine; as your only quercetin it delivers too little to match the evidence base.
A high 'Nx absorption' number distracts from absolute dose. Multiplying a tiny amount still leaves a tiny amount, which is exactly the trap this product's marketing invites.
As a cheap phytosome micro-dose to round out a vitamin C stack, Bio-Quercetin is harmless and inexpensive. As a standalone immune supplement it's the wrong tool: no absorption multiplier turns 15 mg into a study-relevant dose, so most buyers should skip it in favor of a real-dose phytosome.
Check Life Extension on AmazonConfirms phytosome delivery raises quercetin absorption, but the trials used far larger doses than 15 mg.
Immune benefit was seen at 1000 mg/day, roughly 60x this product's dose, underscoring the dose gap.
