Quercetin thyroid interaction

Hi,

So I've been getting a lot of relief from herxes by taking high doses of Quercetin.

However, the last few days I've been feeling progressively worse. I started feeling really exhausted (even more than usual), I started having hand tremors a couple times, I felt really bloated and I went from being hungry to not at all, back and forth.

Suddenly I stumbled upon a thread where someone was asking if you can take Quercetin if you're hypothyroid. With most replies being that it wasn't a good idea.

So I did some searching and confirmed that it shouldn't be taken if you're hypothyroid. As a test, I took an additional dose of thyroid meds and some iodine, even though I had already taken it in the morning.

Several hours later, I'm feeling a lot better. I still have all my Lyme symptoms like fatigue of course, but I could feel that hypothyroid feeling fade away.

So I wanted to share that just in case someone has the same issue.

Here are the things I found:

The flavonoid quercetin inhibits thyroid-restricted genes expression and thyroid function
https://pubmed.ncbi.nlm.nih.gov/24447974/

"The data raise the possibility that quercetin may be a novel disruptor of thyroid function, which has potential effects on, or use in, the therapy of thyroid diseases."
https://academic.oup.com/endo/article/149/1/84/2454911

"Quercetin and its relatives work in two ways to interfere with thyroid hormone metabolism. 1. They reduce activity of thyroperoxidase, the enzyme required to insert iodine into thyroid hormone; and 2. they reduce activity of hepatic deiodinase, a liver enzyme required to activate thyroid hormone."
https://www.diagnosisdiet.com/full-article/foods-that-cause-hypothyroidism

Thank you astro!! That's a great way to put it + insight.

As you know I already have thyroid issues, so this was the last thing I needed haha.

I also thought it was interesting that I would constantly feel like this later in the day, but not that much in the mornings, except right when I woke up.

But now that I think of it:

1) I always took quercetin later in the day.
2) more time has elapsed since I took my thyroid medication (I always take it in the morning).
3) prior to taking my thyroid medication in the mornings I still felt bad.

So it makes sense to me in many ways.

Interesting.

I’m taking Quercetin again - along with curcumin, magnesium threonate, taurine and one more that I’m forgetting. (Dr J suggested them)

Awhile back (years) I was taking Quercetin and I ended up with what looked like bruises on my toes.
I stopped taking it.

This time around I haven’t (so far) got the bruising - but I haven’t been consistent with taking it daily either.

Nothing to do with thyroid tho.

thanks for raising this Rainy

i have hashimoto's also and had quercetin on my list to try to see if it would help calm any symptoms down - but this gives me pause.

ref the conflicting info on quercetins effects

i wonder if in small quantities its anti-inflammatory properties actually help conversion of T4 to T3 - as this step is known to be reduced by chronic inflammation and quercetin is a pretty good general anti-inflammatory.

but in larger quantities its deiodinase enzyme inhibition effects come more to the fore in a dose dependent manner

Hi guys,

Thank you all for the replies.
Yes, I definitely think, as Garzie pointed out that it's dose dependent.

I also think that what JMF said about 3 weeks on 1 week off makes a lot of sense. It was, I think, in my 4th week of taking it consistently when it went wrong. I have stopped taking it now.

I will keep it around for if I get covid, but other than that, it scared me enough to not take it anymore.

The doses I would take would depend, ironically, on how bad I was feeling. So I would take anywhere from 1.2 grams to twice that.

The bottle says take 800 mg, so yes I was taking higher doses.

In regards to the positive studies saraeli, that's interesting, I haven't seen those so unfortunately I can't comment on it, but I think the same might apply, that it's dose dependent indeed and like Garzie pointed out also about the anti-inflammatory benefits.

I did see some studies that say it could be helpful for hyPERthyroidism and thyroid cancer.

Thank you so much sunny, that is so tremendously helpful to hear.