To all experimenters taking oral quercetin:
If you are taking quercetin orally in hopes of having some effect on senescent cells, you are not going to have any luck. I hate to be blunt but quercetin aglycone is just not orally bioavailable.
What's quercetin aglycone?
Quercetin aglycone is quercetin that has not been modified by the liver.
Graefe, E. U. et al. Pharmacokinetics and bioavailability of quercetin glycosides in humans. The Journal of Clinical Pharmacology 41, 492–499 (2001).
"The bioavailability of the aglycone quercetin is, however, very poor. No free quercetin could be detected in human plasma after oral intake of high amounts of quercetin. Quercetin circulates in plasma only in conjugated form, [...] Furthermore, after oral intake of the aglycone, even the total quercetin plasma concentrations measured after [analytical enzymatic] hydrolysis of quercetin conjugates [in plasma samples] were very low."
Notice that they did not say "5% free quercetin could be detected."
Also notice that they did not say "1% free quercetin could be detected."
They said "No free quercetin could be detected".
None, zero, zilch, nada.
When you eat quercetin (the aglycone), after it leaves your digestive system, it enters your liver and is immediately glycosylated. The studies that show quercetin killing senescent cells are for the aglycone, meaning quercetin with NO glycosylation. Once you attach a sugar molecule to quercetin (or really anything), it's a different molecule. It's a >really< different molecule. Glycosylation is how the liver inactivates toxic molecules like quercetin and other toxins and drugs in general. Once a toxin has a sugar attached to it, it makes it really hard for the toxin to make it across cell membranes, makes it impossible to bind to its pharmacophore and very easy to be washed out of the kidneys. Flavones like quercetin are extremely common in nature. Thus, our livers have had millions of years to get very, very good at quickly inactivating them.
It's no small coincidence that the Phase I clinical trial using quercetin in chemotherapy with people who actually have cancer used it intravenously. Please check out:
Ferry, D. R. et al. Phase I clinical trial of the flavonoid quercetin: pharmacokinetics and evidence for in vivo tyrosine kinase inhibition. Clin. Cancer Res. 2, 659–668 (1996).
From the article above, quercetin aglycone is pretty much insoluble in water. They reference a study in in 1975 where quercetin was given intravenously dissolved in ethanol. The researchers finally ended up dissolving it in DMSO and giving that intravenously. I don't know how much you all know about the wisdom of injecting ethanol or DMSO into a vein. I can tell you one does not even consider doing some thing so crazy/stupid unless 1) Someone is going to die otherwise and 2) There is absolutely no other way to get the drug into you. That is sadly the case with quercetin aglycone. All quercetin aglycone going into your digestive system has to make it passed your liver. Quercetin aglycone does not make it passed the liver, at all. Hence, the decision to go the dangerous intravenous route in the trial referenced above.
If you still don't believe me, take a look at the paper above to see the side effects of actual unmodified quercetin aglycone at doses expected to kill senescent cancer cells: Renal toxicity and severe nausea. Any of you experiencing those two? Probably not, since you all likely have functional livers attached between your digestive systems and hepatic veins.
"I've taken a bunch of quercetin and dasatinib and noticed not a lot has happened except now I'm thinner. What does this mean?"
Congratulations, your dasatinib has probably worked just fine to kill your harmful senescent fat cells. You are one of the first humans on earth to do this. However, the quercetin you took probably did jack squat. Be happy those senescent cells are gone. If you really want to kill senescent cells other than preadipocytes you are going to have to either:
1) Find a way to take quercetin IV.
Difficult but not recommended. I have a background as a chemist and biomedical scientist and I'm still afraid of all the ways that might kill me. (I have a plan that does not involve DMSO for those reckless and irresponsible enough to attempt this.)
2) Find another drug to supplement dasatinib.
Navitoclax doesn't kill pre-adipocytes so it makes a good partner to dasatinib. Yeah, I know it's expensive. Did you really think this was going to be easy?
Edited by jmorris, 25 April 2017 - 03:28 AM.