[2] Patients should contact their GP if they experience: Side effects from B12 injections (though these are rare and usually mild) Difficulty attending scheduled injection appointments, as missed doses may lead to symptom recurrence New symptoms developing during treatment Concerns about treatment effectiveness or duration Changes in other medications that might affect B12 absorption Suspected adverse reactions to B12 treatment can be reported through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk)
In addition to be part of proteins, an important source of cysteine consumption is the synthesis of methionine and glutathione
PMC 7703558
This may include using the voice in a strained way, yelling, speaking over background noise for long periods of time or singing in a less than efficient way
Employ consistent, periodic lab work and clinical reevaluation to weigh possible long term benefits against risks like hormonal suppression or metabolic alterations
For practical purposes, if a patient is on an SSRI or similar antidepressant, they generally must not receive MB unless it is absolutely medically necessary (such as for a life-threatening methemoglobinemia that cannot be otherwise managed)