Summary

Quercetin is a first-line natural supplement for mast cell activation syndrome, MCAS. It is a natural mast cell stabiliser. Taken before or with meals, it can reduce reactions to foods. In those less sensitive to food, it can still be helpful with other mast cell issues.

Stabilising mast cells is important – this is the only way to reduce symptoms longer term and prevent worse flare-ups.

Many long covid patients also have symptoms of MCAS. This seems especially common in women, queer and neurodiverse people, and those who initially had milder symptoms during acute covid.

MCAS is extremely highly comorbid with Ehlers-Danlos syndromes. Some believe everyone with EDS has the potential to develop MCAS when triggered – for many, long covid has been that trigger.

Quercetin is tagged as helpful for EDS due to the findings of the first paper.

Known effects

Some people react badly to quercetin. Some suggest starting with a low dose and easing yourself in. A minority can’t take it – and can benefit from alternatives such as berberine instead. I don’t know much about the alternatives. Some sources suggest it must be taken alongside bromelain or vitamin C for proper absorption.

I initially reacted badly to it – it would raise my heart rate. This effect calmed when my MCAS became a little milder due to a positive reaction to the covid jab. Now I tolerate it well.

Rose takes this like this

I take capsules with approximately 500 mg quercetin content twice a day, 1-0-1. However, I have only mild gut symptoms due to high curcumin intake. It is recommended to take it in before every meal, up to 3 times a day, and in combination with vitamin C after the meal (dose recommendations for vitamin C vary) for the best effect – quercetin to prevent release of histamine and vitamin C to break up what actually does get produced. Higher doses may be possible – not something I have looked into.

Research

Mast cell disorders in Ehlers–Danlos syndrome (2017)
https://onlinelibrary.wiley.com/doi/10.1002/ajmg.c.31555
Detailed paper on mast cell issues in EDS.

Quercetin Is More Effective than Cromolyn in Blocking Human Mast Cell Cytokine Release and Inhibits Contact Dermatitis and Photosensitivity in Humans
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3314669/
Cromolyn is the pharmaceutical option that works well in MCAS, but this study shows quercetin beats cromolyn in the two tested scenarios.

Many more studies exist… have a google.