Form Comparison

Enzymatically Modified Isoquercitrin vs Quercetin Phytosome

How enzymatically modified isoquercitrin and quercetin phytosome differ in potency, absorption, tolerance, and cost.

This page contains affiliate links. Titrate earns a small commission when you purchase through them, at no cost to you. This does not affect our recommendations.

Quick verdict. Both fix plain quercetin's poor absorption by different routes: EMIQ uses water-soluble glucosides absorbed after hydrolysis in the small intestine, and Quercefit uses a lecithin complex that raised plasma quercetin up to twentyfold in an industry-funded study. No head-to-head trial exists, so either is a reasonable pick. EMIQ suits drink mixes, and the phytosome suits a 250-500 mg capsule.

Side by Side

Enzymatically Modified Isoquercitrin (EMIQ) Quercetin Phytosome (Quercefit)
Absorption Moderate Moderate
How it is absorbed Quercetin glucoside with added glucose units. Water soluble, and absorbed after hydrolysis in the small intestine, with much higher plasma quercetin than the aglycone in human studies. Lecithin complex. Plasma quercetin was up to about twentyfold higher than with the unformulated aglycone in a crossover study.
Typical dose Per product 250-500 mg daily
Common uses general flavonoid supplementation allergy symptoms (marketed)
Side effects None notable. Headache.
Cost Moderate Moderate
Also called isoquercetin, alpha-glycosyl isoquercitrin Quercefit, quercetin-lecithin complex

When to Choose Enzymatically Modified Isoquercitrin (EMIQ)

Choose enzymatically modified isoquercitrin when you want a water-soluble form. Mirrors the glucoside form that makes onion quercetin well absorbed.

Enzymatically Modified Isoquercitrin (EMIQ)

Water soluble and well absorbed in human studies. Less common on shelves.

What to look for: EMIQ or alpha-glycosyl isoquercitrin named, with quercetin-equivalent content stated.

Find on iHerb Affiliate link

When to Choose Quercetin Phytosome (Quercefit)

Choose quercetin phytosome when you want higher blood levels at a lower dose. Same manufacturer as Meriva curcumin; the absorption study was industry funded.

Quercetin Phytosome (Quercefit)

Much better absorbed than plain quercetin at a lower dose, with industry-funded data.

What to look for: Quercefit or quercetin phytosome, 250-500 mg daily.

Find on iHerb Affiliate link

Products on Titrate

3,011 of the 214,745 labels in the NIH Dietary Supplement Label Database list quercetin as an active ingredient (1,502 on market). 495 are sold as quercetin products by name.

Open supplement search

Quercetin does not have its own search category yet. Each product above links to its full label in the NIH database.

Related

References

Linus Pauling Institute Micronutrient Information Center, Oregon State University. Flavonoids.

Ferry DR, Smith A, Malkhandi J, et al. Phase I clinical trial of the flavonoid quercetin: pharmacokinetics and evidence for in vivo tyrosine kinase inhibition. Clin Cancer Res. 1996;2(4):659-668.

Heinz SA, Henson DA, Austin MD, Jin F, Nieman DC. Quercetin supplementation and upper respiratory tract infection: a randomized community clinical trial. Pharmacol Res. 2010;62(3):237-242.

Murota K, Matsuda N, Kashino Y, et al. alpha-Oligoglucosylation of a sugar moiety enhances the bioavailability of quercetin glucosides in humans. Arch Biochem Biophys. 2010;501(1):91-97.

Weng Z, Zhang B, Asadi S, et al. Quercetin is more effective than cromolyn in blocking human mast cell cytokine release and inhibits contact dermatitis and photosensitivity in humans. PLoS One. 2012;7(3):e33805.

Serban MC, Sahebkar A, Zanchetti A, et al. Effects of quercetin on blood pressure: a systematic review and meta-analysis of randomized controlled trials. J Am Heart Assoc. 2016;5(7):e002713.

Riva A, Ronchi M, Petrangolini G, Bosisio S, Allegrini P. Improved oral absorption of quercetin from quercetin phytosome, a new delivery system based on food grade lecithin. Eur J Drug Metab Pharmacokinet. 2019;44(2):169-177.

Di Pierro F, Derosa G, Maffioli P, et al. Possible therapeutic effects of adjuvant quercetin supplementation against early-stage COVID-19 infection: a prospective, randomized, controlled, and open-label study. Int J Gen Med. 2021;14:2359-2366.