5 replies to this topic

[mrak1979]

Anybody still taking quercetin with resveratrol? If so, what ratio and why?

[Anthony_Loera]

Want low priced quercitin?

Eat some onions...

A

[maxwatt]

Want low priced quercitin?

Eat some onions...

A

Or drink a few ounces of cirtus juice. That would be about the right amount.

[mrak1979]

I heard that quercetin supps inhibit resveratrol metabolism... but I guess only very small amount is needed... anybody know what amount is needed?

[maxwatt]

I heard that quercetin supps inhibit resveratrol metabolism... but I guess only very small amount is needed... anybody know what amount is needed?

We are guessing, AFIK. Niner once suggested that 30 mg, the amount one might get by eating an orange, other citrus or citrus juice, or some onions, would be a safe upper limit. Few formulations that contain resveratrol with quercetin have that little. Most have far more. Querctin supplements have an order of magnitude more. I do know that taking 250 mg quercetin supplements, appeared to negate the positive effect of resveratrol for my arthritic joints after three days. I assume this was due to blocking Sirt1, which in turn ceased inhibiting nfKappa-B, leading to increased inflammation. The initial effect of quercetin was positive, I assume because it inhibits COX2 inflammation.

Drinking grapefruit juice with my resveratrol appeared to make it more potent, as if I were taking a larger dose. I assume it is because I was getting about 30 mg of quercetin and it was increasing serum levels of resveratrol, while the antagonistic effect of Sirt1 was not sufficient to block resveratrol's agonistic effect.

[niner]

I heard that quercetin supps inhibit resveratrol metabolism... but I guess only very small amount is needed... anybody know what amount is needed?

We are guessing, AFIK. Niner once suggested that 30 mg, the amount one might get by eating an orange, other citrus or citrus juice, or some onions, would be a safe upper limit.

I don't remember saying that, but maybe it was something in a PM. That wouldn't be safe upper limit as in "dangerous to take more", though. People take way more than that all the time, even through dietary sources. We are in fact guessing, as the disposition of quercetin in the body is fairly involved. It is highly conjugated, perhaps even more than resveratrol, for one thing. It's also highly protein-bound. It has an alleged picomolar IC50 for inhibition of resveratrol sulfation, a number that some of us find almost difficult to believe. Whatever the truth of that is, it has to be balanced against the various ways in which the quercetin aglycone is taken out of circulation. Quercetin (and luteolin, and probably a lot of other related compounds) will also induce higher expression of the very enzymes responsible for their metabolism, so even if it works today it may or may not work next week. Hedgehog had some quercetin in at least one of his formulations that he did human pharmacokinetic testing on, although as I recall there were some problems with that experiment that might have complicated the interpretation. I still think there is a reasonable chance that some quercetin is a net positive in terms of improving resveratrol metabolism, but it's really hard to say how much is the right amount. Staying somewhere near the high end of dietary amounts is at least unlikely to hurt you.