ghk-cu/bpc-157/tb-500/kpv KLOW Blend BPC-157/TB-500/GHK-Cu/KPV Blend Research: Dosing, Benefits

[1] [2] Blood levels of B12 may rise quickly following injection, though elevated blood levels do not immediately translate to symptom resolution

Source and Quality This is where costs vary most dramatically

Mild, short-lived reactions can include soreness at the injection site, a brief flushing sensation, mild bruising, or, very rarely, mild nausea

Huang T, Wang J, et al

Always good to have a reason I have also had this happen when my folate was low , it may be worth you getting it checked I had self inject my B12 every 4 weeks for the last 20+ (cannot really remember how long accurately), and 2 months ago got a similar 'electric shock tingling' all over my body - head, face, arms, hands, legs, feet etc within a couple of minutes of injecting, which lasted about 3 seconds or so