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    Created in 2008, Phoenix Rising is the largest and oldest forum dedicated to furthering the understanding of, and finding treatments for, complex chronic illnesses such as chronic fatigue syndrome (ME/CFS), fibromyalgia, long COVID, postural orthostatic tachycardia syndrome (POTS), mast cell activation syndrome (MCAS), and allied diseases.

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Senior Member
Hi all! I’m very confused and hope someone can help me. I really would like to take Quercetin for my MCAS but I also have hydrogen sulfide Sibo which causes sulfur intolerance. There’s conflicting information regarding quercetin becoming metabolite of sulphur in the body. When I message companies that make Quercetin from the sophora japonica flower, they assure me there’s no sulphur molecule in the product. But why am I reading that it converts to quercetin sulfate after metabolism? Am I misinformed? Is this safe for sulphur intolerance because it converts AFTER metabolism and not right at ingesting? And one company mentioned the quercetin is from the rutin of the sophora japonica flower, if it makes a difference. And one more question, does Quercetin need to be taken with Bromelain or Vitamin C? Bromelain is somehow related to sulphur so that leaves me with Vitamin C. Thanks!