Thanks for your welcome, mrsD. No, I haven't been tested for B12 deficiency - it's about the only one I haven't been tested for! It's funny you mentioned acid lowering drugs as I developed GERD in January and was put on a proton pump inhibitor (PPP) for about four months. I'm off the PPP now but I still take Gaviscon as and when I have acid reflux symptoms. I think I first noticed my twitches and tingling sensations about two or three weeks after I had my GERD symptoms. But I have been taking a B1-B6-B12 combo supplement, somewhat irregularly, since then. Perhaps I haven't been taking enough? As of June, my blood sugar and thyroid levels are normal. I'm going for another complete blood profile in January. I shall request for a B12 test then.