Common side effects The most frequently reported side effects are mild and transient: Dizziness (most common, usually related to injection speed) Headache (typically resolves within 24 hours) Skin flushing (related to vasodilation effects) Nausea (more common at higher doses) Fatigue or insomnia (varies by individual) Agitation or anxiety (infrequent) Weight loss (reported in some longer-term studies) Feeling hot (transient, related to administration) Most of these side effects correlate with administration speed rather than the compound itself
People can become deficient when they are not eating enough vitamin B12 rich foods, or their bodies may struggle with absorbing the vitamin
Treating chronic fatigue syndrome: a study into the scientific evidence for pharmacological treatments
H., Rogers, J., Scherr, S., Benoit, R
DOI Maquart FX, Pickart L, Laurent M, et al