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quercetin, kidney damage

alex3619

Senior Member
Messages
13,810
Location
Logan, Queensland, Australia
This is not a surprise. Quercetin has been suspected of altering eicosanoid production. A number of eicosanoids regulate proper blood flow in the kidneys. So long term use may alter blood flow and even tissue repair.

I suspect that other substances including resveratrol, which I am taking, may have the same effect if misused.
 

Changexpert

Senior Member
Messages
112
Darn it, I took quercetin for about a month in the past. No wonder my symptoms got worse during that period.
 

GracieJ

Senior Member
Messages
772
Location
Utah
What is a safe dose to be on and for how long? I started quercetin a week ago with great results, and had been planning to bump my daily dose up to the 1500mg recommended on several sites. As it is, right now I am at 1gm per day, which is considered a high dose.

What do I need to look for to do this safely? The results so far are phenomenal. Breathing, swallowing, digestion, arthritis, and skin issues have all settled down, giving me relief.

However, at the same time, I started getting headaches as of yesterday, and have had kidney pain for two days with no explanation. Is this something to use for a few days at a time, then stop?

I think I will back this off to one 500mg capsule daily until I know more.
 

CantThink

Senior Member
Messages
800
Location
England, UK
You should take periodic breaks from taking quercetin.

At high doses (greater than 1 g per day), there are some reports of damage to the kidneys.

Source: Quercetin | University of Maryland Medical Center

The other source quoted by Sherlock said:

Quercetin has been safely used in amounts up to 500 mg twice daily for 12 weeks. It is not known if longer-term use or larger amounts are safe.
 

Changexpert

Senior Member
Messages
112
What is a safe dose to be on and for how long? I started quercetin a week ago with great results, and had been planning to bump my daily dose up to the 1500mg recommended on several sites. As it is, right now I am at 1gm per day, which is considered a high dose.

What do I need to look for to do this safely? The results so far are phenomenal. Breathing, swallowing, digestion, arthritis, and skin issues have all settled down, giving me relief.

However, at the same time, I started getting headaches as of yesterday, and have had kidney pain for two days with no explanation. Is this something to use for a few days at a time, then stop?

I think I will back this off to one 500mg capsule daily until I know more.
FWIW, I took 800 mg along with 185 mg of Bromelain. Quercetin must be combined with Bromelain for best absorption. Most people use somewhere around 500 mg and 1000 mg. There was a rat study suggesting that consumption of Quercetin at 50 mg/kg body weight would lead to brain tumors. This means for average females around 2.5g/day and average males around 4g/day, assuming 50 kg and 80 kg respectively.

Source: http://www.sciencedirect.com/science/article/pii/S0278691513007473
 

Sherlock

Boswellia for lungs and MC stabllizing
Messages
1,287
Location
k8518704 USA
When we hear of how grapefruit interacts with medications (making them in effect stronger by inhibiting breakdown in the liver via CYP3A4 and CYP2C9 enzymes), it seems that quercetin is the component in grapefruit that does so. This relates to @Sushi's comment above.

Also, with kidney pain I'd wonder if there is some pre-existing kidney problem.
 

GracieJ

Senior Member
Messages
772
Location
Utah
Thanks, everybody, I did read both links.

Just sorting out all the pieces, very much appreciate hearing from others about their experiences.
 

godlovesatrier

Senior Member
Messages
2,545
Location
United Kingdom
I get this kidney issue too. I think it started with regular egcg intake. Didn't know at the time that this could damage my kidneys. Saying that my function tests recovered to pre baseline. But the kidneys get aggrevated very easily now so I assume something isn't right.