It's the latest celebrity craze, with everyone from Madonna and Victoria Beckham to Justin Timberlake and Katy Perry supposedly getting a boost from vitamin B12. But what does it do, and do you need one?
What is vitamin B12?
Posh claims it kept her in her usual incredible shape throughout pregnancy, while Chelsea Handler suggested it gave her libido a boost. Others have been known to use injections to help boost their energy levels. And the truth is that B12 is an essential vitamin. It is involved in the body's metabolism, synthesis of fatty acids, energy production, the formation of red blood cells, and helps to keep the brain and nervous system functioning properly.
What if I'm not getting enough?
If you are lacking in vitamin B12, you could be prone to anaemia, which causes fatigue, breathlessness, headaches, mouth ulcers and mood swings, among other symptoms. Those on a strict vegan diet and the elderly are at greater risk of a B12 deficiency.
How do I know if I'm deficient?
As well as the symptoms associated with anaemia, a lack of vitamin B12 can have serious consequences. According to a case report published in the New England Journal of Medicine, one 62-year-old man first noticed a numbness and pins and needles in his hands, before experiencing joint pain, shortness of breath, yellow-tinged skin and difficulty walking. A further article in the journal in January suggested that left untreated, a B12 deficiency could lead to depression, paranoia, memory loss, loss of taste and smell and even incontinence.
If you are in one of those at-risk categories, i.e. over the age of 50 or on a vegan diet, and experience any of the above symptoms, it is worth checking with your doctor.
So do I need an injection?
As a water soluble vitamin, unless you are deficient in B12, your body will simply get rid of any excess, so you're likely throwing money away on something you should be getting from your diet.
However, if blood tests do indicate that you are lacking in this vital vitamin, then injections or high-dose supplements may be prescribed.
Remember, in the UK, a vitamin B12 injection is only available on prescription and must be performed by a medical professional. If that's not the case, walk away.