020 7916 0029 Call Patient portal Portal Register as a new patient Register Doctors portal Book Now Book Now

Not an emergency service. If you or someone else is seriously unwell — for example chest pain, breathing difficulty, heavy bleeding or collapse — call 999. For urgent advice when it is not life-threatening, call NHS 111.

Recovery & Aftercare Guide

Vitamin B12 injection

An intramuscular injection, usually into the upper arm. Minimal aftercare.

Important. Your individual instructions from your treating clinician take precedence over this general information. If anything here differs from what your clinician has told you, follow your clinician’s advice and contact the hospital if you are unsure.

Overview

Vitamin B12 is given as an injection into a muscle, most often the upper arm.

The appointment is short. There is no recovery period and you can carry on with your day.

Before your procedure

  • Tell the team about all medicines, particularly anticoagulants, and about any bleeding disorder.
  • Tell the team about previous reactions to injections.
  • Wear a top with a sleeve that rolls up easily to the shoulder.
  • Eat and drink normally.

Aftercare

Injection site

Aching or tenderness in the muscle for a day or two is common.

Bruising

A small bruise at the site is common and fades within a week.

Activity

No restrictions. Avoid heavy gym work with that arm on the same day if it feels sore.

Bathing and driving

No restrictions.

Repeat doses

If a course or maintenance schedule has been arranged, attend as planned. Do not alter the schedule yourself.

Red flags — when to seek help

These lists are not exhaustive. Trust your judgement and seek advice if you are worried.

Emergency Call 999 or go to your nearest emergency department

  • Difficulty breathing, throat or facial swelling, or a widespread rash shortly after the injection
  • Feeling faint with a rapid heartbeat shortly after the injection

Contact us Contact the hospital, or call NHS 111 out of hours

  • Spreading redness, heat or swelling at the injection site after 48 hours
  • Pus at the injection site
  • Arm pain that is worsening rather than settling

Tower Bridge Hospital, 97–99 Whitechapel Road, London E1 1DT. Telephone 020 7916 0029. If in doubt and the situation is not life-threatening, call NHS 111.

Frequently asked questions

Will my arm be sore?

Mild aching for a day or two is common and settles on its own.

Can I exercise afterwards?

Yes, though you may prefer to avoid heavy upper-body work on the same day.

How often will I need injections?

This depends on why B12 is being given. Your clinician will explain the schedule.

Can I drive afterwards?

Yes, there are no restrictions.

More information

Clinical reviewer
Dr Haydar Bolat, Clinical Director
Review date
21 July 2026
Review by
21 July 2027
Version
1.0
Book Now