migraine after b12 injection can vitamin injections cause headaches I've had a since Sept 4th. I took The Weird Connection Between B12

Not a peptide

The injection site can become red or slightly inflamed (red slight bump) afterward and this is nothing to be concerned over

But for most people, the effect is more of a gradual return to your normal baseline, not a sudden, dramatic spike in energy

After 2 to 3 weeks, the user notices the peptide "stopped working." It did not stop working

Still, side effects from B12 supplements are possible, especially at higher doses, and include: Headache Nausea Vomiting Fatigue Weakness Diarrhea Tingling in the hands and feet Nasal spray Vitamin B12 is also available in a nasal spray

For benefits like tissue repair or skin improvements, it can take a bit longer as your body needs time to rebuild on a cellular level