I have B12 deficiency due to long tem (6 years) use of Omeprazole. I have had most of the symptoms of B12 deficiency and most have gone following B12 therapy (Jarrow sublingual tablets) since 23 June. My most concerning symptom has been progressive muscle fatigue (jelly legs on exercise) and muscle weakness and this has not responded whatsoever to B12 therapy (it had got worse if anything). I believe what I am experiencing is metabolic rather than neurological. I have had a very high CPK test result of 6,332 and have been referred for polymyositis. Does anyone have any experience of recovery of muscle fatigue due to B12 deficiency and could you describe your experience please. Many thanks everyone out there!