Advice about Vitamin B12 Injections

Everyone who has UNDERGONE Bariatric Surgery (such as gastric bypass, duodenal switch, one anastomosis gastric bypass or sleeve gastrectomy) needs to get Vitamin B12 injections every three months, as they are at a higher risk of getting a deficiency (low level).  Persistently low levels of Vitamin B12 in the body can lead to serious complications including nerve damage, which can be irreversible. Therefore lifelong Vitamin B12 is required after Bariatric Surgery. 
During the pandemic you may not be able to attend your GP surgery to have these Vitamin B12 injections. This understandably can cause you to feel anxious.  If you are unable to receive your B12 injections as usual, please follow the advice in the table below.

If you have recently experienced neurological symptoms such as extreme tiredness, pins and needles, disturbed vision, poor memory or low mood…

Continue with scheduled 3 monthly vitamin B12 injections. 

If you are self-isolating please ask your GP to prescribe Oral Cyanocobalamin 1000 micrograms/day for the time being, until Vitamin B12 three monthly injections can be resumed 

If no recent symptoms... Ask your GP to prescribe Oral Cyanocobalamin 1000 micrograms/day.
If you cannot access oral cyanocobalamin from your GP…

Purchase Vitamin  B12 over the counter, take 1000 micrograms/day by mouth

Examples linked below:

Holland & Barrett

IMPORTANT: As soon as you are safely able to, re-start your B12 injections.

Taking all of the multi-vitamins and minerals that you has been advised to will help to maintain your immune system, and therefore protect against infections.  
If you have any questions regarding the above, please call us on 0208 510 7496 (option 5). 


We are one of the few NHS centres in the south-east providing a full menu of surgical solutions to  patients troubled by obesity.

Our multi-disciplinary approach will ensure that you are consistently supported throughout your treatment with us, and that you can access the right advice and support at the right time. All our treatments adhere strictly to the latest guidance provided by the National Institute of Clinical Excellence, NICE.

Services available
our menu of surgical solutions include:

  • adjustable gastric banding
  • sleeve gastrectomy
  • gastric bypass (Roux-en-Y and duodenal switch).

TOC information for GPs

Contact us
Leave voicemail on 020 8510 7496
or email
Please include your name, hospital number, contact details and brief message. 

Useful websites

NHS Choices Weight loss surgery
Weight loss surgery information website

Referrals to bariatric surgery

Making an appointment
To access our specialist bariatric (weight loss) surgical service, you will need to be referred by your GP or by another hospital consultant.
This is dependent on you having already tried other treatments such as your local tier 3 specialist weight management service and weight loss medications.

How to make a referral

  • Appointments and referrals can be made by you or your GP via The Electronic Referral Service (e-RS). This is Homerton's preferred method of receiving referrals. 
  • If a Pre-Operative Bariatric referral - GP or hospital consultant to complete all aspects of the  Bariatric-pre-op-referral including weight, height, BMI and co-morbidities.
  • If a Post-Operative Bariatric referral - GP or hospital consultant to complete all aspects of the  Post - Operative Referral including weight, height, BMI and co-morbidities’.
  • Attach the referral form to e-RS
  • Please contact us if you have any queries.
  • Our email is

Patient to complete & bring to initial appointment
Please ensure the patient questionnaire is completed and brought to your first appointment along with a copy of your recent prescription medications. Failure to do so will delay your appointment.

First steps

Our Centre of Laparoscopic Surgery's specialist obesity surgeons work together with our metabolic physician, bariatric nurse specialist, bariatric specialist dietitian and bariatric specialist physiotherapist to ensure that you receive appropriate specialist care and advice.

All our staff are experienced obesity specialists and they are enthusiastic to help patients reduce their weight in the most appropriate and safest way possible.

What is obesity?
Obesity is caused by consuming more calories than the body uses over a sustained period of time; this excess is stored in the body as fat. It is a chronic condition that can be difficult to treat.

There are many causes of obesity including metabolic, environmental, genetic, hormonal and a disordered relationship with food. Those who suffer with obesity are also more likely to develop a range of other diseases including diabetes, coronary heart disease, high blood pressure, sleep apnoea and early arthritis; which can only be managed by losing weight.

Is surgery for you

Advances in technology mean that surgeons can now make a person's stomach smaller, which reduces the amount that can be eaten at any one time.

There are two ways that surgery can help weight loss:

  • By decreasing food intake: surgeries include gastric banding, gastric bypass and sleeve gastrectomy. These limit the amount of food that can be held by the stomach. 
  • By causing food to be poorly digested and absorbed: such as the duodenal switch. This connects the stomach to a lower section of the small intestine, which means that the amount of calories absorbed into the body is decreased.

If you are obese and have been unsuccessful with other weight loss methods or you have an obesity-related disease, then surgery may be an option for you.

You may be eligible for surgery if you:

  • have a BMI (body mass index*) of 35 or more with an obesity-related physical problem such as diabetes, high blood pressure, sleep apnoea or early arthritis that could be improved with weight loss
  • have a BMI of 40 or more have failed to achieve or maintain clinically beneficial weight loss through non-surgical methods for at least six months (unless you have a BMI over 50, in which case you will go straight to surgery)
  • have a commitment to life-long follow up.

It is important that you consider all the options, and know the risks and benefits, before deciding to proceed with obesity surgery. At Homerton, you will have access to a range of professionals who will be able to discuss the other aspects of your healthcare such as nutrition, aftercare and physical activity.

What is the benefit of laparoscopic surgery?
We perform all our obesity surgery by using laparoscopy. Laparoscopic or 'keyhole' surgery avoids the need for a large incision, as in open surgey; instead the operations are performed through small incisions using long thin surgical equipment and video cameras.

This means that patients have minimal scarring, less pain and recovery times are much quicker.