• Welcome to Phoenix Rising!

    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.

    To become a member, simply click the Register button at the top right.

Search results

  1. G

    Cannot tolerate oral B12 – causes shortness of breath and tachycardia. Why?

    LynnJ - I was getting heart palpitations quite often a abour 4 years ago, I've had them all my life, but nothing like I was experiencing then. I was taking a B12 supplement at the time and one afternoon I realized I had forgotten to take it, I took the sublingual and within 5 minutes my heart...