Help understand what to do . I read “ Why Quercetin, Vitamin C and NAC should be taken together to prevent Quercetin toxicity

I've been researching the benefits/risks of grouping certain supplements together and I came across this really important information I wanted to share with my fellow supplement enthusiasts

When taken on it's own, Quercetin can quickly oxidize.  Oxidized quercetin forms quinones. In the presence of protein thiol groups, these quercetin-quinones will form toxic compounds that go on to exert pro-oxidant effects and cause damage throughout the body.

Taking vitamin C with quercetin will protect quercetin from oxidizing and create safe quercetin metabolites. Delivering quercetin with vitamin C in the presence of healthy glutathione status will increase quercetin’s clinical efficacy in two critical ways:

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1. Vitamin C potentiates the activity of quercetin by recycling quercetin back to its reduced form. This increases quercetin’s bioavailability and effectiveness as an antioxidant.
2. N-acetyl cysteine (NAC) supports healthy glutathione status and will shunt quercetin down safer metabolic pathways. This stimulates the body to conjugate quercetin-quinones via Phase II detox pathways.

This is why quercetin should always be co-administered with vitamin C and NAC. When taken together, these nutrients have a synergistic effect beyond what any of them can provide individually. [Plus, mounting evidence supports their use for safe and effective immune support through their influence on improved barrier function, NK cell activity, and B-cell and T-cell maturation and differentiation.](https://www.lifestylematrix.com/blog/5-safe-and-effective-nutrients-for-vulnerable-populations-during-covid-19/)

[https://www.lifestylematrix.com/blog/the-quercetin-paradox-the-secret-to-preventing-toxic-quercetin-metabolites/](https://www.lifestylematrix.com/blog/the-quercetin-paradox-the-secret-to-preventing-toxic-quercetin-metabolites/)” Then I read “ Objective: Quercetin bioavailability exhibits high interindividual variation for reasons that remain unclear. We conducted a 24-h pharmacokinetic study to investigate whether individual differences in circulating antioxidants, oxidative stress and inflammation, and intestinal permeability affect quercetin bioavailability.

Methods: Healthy adults (n = 9 M/7 F; 34.3 ± 4.5 y; 27.0 ± 1.7 kg/m(2)) ingested 1095 mg quercetin aglycone with a standardized meal. Plasma antioxidants, biomarkers of oxidative stress and inflammation, and endotoxin were measured at baseline (0 h), and quercetin and its methylated metabolites isorhamnetin and tamarixetin were measured at timed intervals for 24 h.

Results: Plasma pharmacokinetics of quercetin, isorhamnetin and tamarixetin were highly variable between participants (CVinter = 37-96%). Plasma vitamin C concentrations (34.6 ± 2.5 μmol/L), but no other antioxidants, were inversely correlated to the Cmax and AUC0 to 24 h of total quercetin (Qtotal; sum of quercetin, isorhamnetin and tamarixetin; r = -0.52 to -0.53; P < 0.05). Plasma endotoxin (0.13 ± 0.01 EU/mL), a surrogate marker of intestinal permeability, was correlated to Qtotal Cmax (r = 0.45; P < 0.05) and tended to be correlated to Qtotal AUC0 to 24 h (r = 0.38; P = 0.07). Additionally, vitamin C was inversely related to C-reactive protein, myeloperoxidase, and endotoxin (r = -0.46 to -0.55; P < 0.05), whereas endotoxin was positively correlated to C-reactive protein (r = 0.73; P < 0.05).

Conclusions: These findings suggest that vitamin C status and plasma endotoxin may be associated with interindividual variations in quercetin bioavailability. Greater quercetin absorption and bioavailability may be associated with poor vitamin C status and increased intestinal permeability in healthy adults.” . So Quercetin is good or not taken with vitamin C?