Call 911 if you have an allergic reaction
It is common to feel fatigued, weak, dizzy, pale or jaundiced skin, and tingly sensations in the hands and feet when you don't have enough B12
This updated 2026 guide walks you through the science behind bacteriostatic water (often referred to as bac water), its role in peptide injections, how to reconstitute peptides correctly, how to use a peptide reconstitution calculator , how to safely store peptides, and document every aspect of your journey along the way
Headaches Headaches are another less common side effect
Do not shake the vial vigorously
Eating a light meal before the injection and staying hydrated can help reduce nausea