self administered b12 injection kits Injections at Home - Safety Guide for Self-Administration pregnancy/breastfeeding B12 Injection Kit: Syringes &
Description
Even though this marker is considered to be the most sensitive marker for B12 deficiency, at the time of this writing, it is not readily available

Maintain healthy brain and nerve function

Babula, P., et al

But, the quantity of cyanide is considered to be clinically irrelevant

This way, you can safely take your medicines without losing out on nutrition
