Vitamin B12 deficiency and the anaemia it causes, and peripheral neuropathy with tingling, burning or numbness, including in diabetes. It is often prescribed alongside other B vitamins.

Vitamin B12 is a cofactor the body cannot make for itself. Mecobalamin is the form the body uses directly, without conversion, in the reactions that build DNA for new red blood cells and that maintain myelin, the insulating sheath around nerves. Restoring it lets the marrow make normal cells and lets damaged nerve sheaths repair.

Usually well tolerated. Occasional nausea, loss of appetite, diarrhoea, headache or rash. Injections can sting at the site.

Find out why the B12 is low rather than simply replacing it, since pernicious anaemia, gut disease or long-term metformin all need their own management. Taking B12 or folic acid without checking both can hide a deficiency while nerve damage continues. Tell your doctor about kidney disease or if you are pregnant or breastfeeding.