There's not enough evidence to show what the effects may be of taking high doses of vitamin B12 supplements each day. Most people should be able to get the amount of folate they need by eating a varied and balanced diet. But as vitamin B12 is not found naturally in foods such as fruit, vegetables and grains, vegans may not get enough of it. But in a few cases when people have taken large amounts of vitamin B6, particularly for more than a few months, the effect can be permanent. This is important and unlikely to cause harm, as it's taken on a short-term basis, but speak to your doctor first.

Vitamins and minerals - B vitamins and folic acid - NHS Vitamins and minerals - B vitamins and folic acid - NHS

Taking 200mg or more a day of vitamin B6 [LK2] can lead to a loss of feeling in the arms and legs known as peripheral neuropathy. There's not enough evidence to know what the effects might be of taking high daily doses of pantothenic acid supplements. The Department of Health and Social Care recommends that folic acid supplements are taken by all women who are pregnant or could get pregnant. The bacteria that live naturally in your bowel are able to make biotin, so it's not clear if you need any additional biotin from the diet. If you're taking folic acid supplements, it's important not to take too much as this could be harmful.You should be able to get all the pantothenic acid you need from your daily diet, as it's found in many foods. There's not enough evidence to know what the effects might be of taking high daily doses of biotin supplements. Get more advice about vitamins and minerals during pregnancy, including who should take a higher dose of folic acid. This is particularly a concern for older people because it becomes more difficult to absorb vitamin B12 as you get older. Taking 17mg or less of nicotinic acid supplements a day, or 500mg or less of nicotinamide supplements a day, is unlikely to cause any harm.

If you're pregnant, trying for a baby, or could get pregnant, it's recommended that you take a 400 microgram folic acid supplement daily until you're 12 weeks pregnant. Women who cannot get pregnant and men should be able to get all the folate they need by eating a varied and balanced diet. Taking doses of folic acid higher than 1mg can mask the symptoms of vitamin B12 deficiency, which can eventually damage the nervous system if it's not spotted and treated.

Folic acid supplements need to be taken before you get pregnant, so start taking them before you stop using contraception or if there's a chance you might get pregnant. There's not enough evidence to know what the effects might be of taking high daily doses of nicotinamide supplements. There's not enough evidence to know what the effects might be of taking high doses of thiamin supplements each day. Some women have an increased risk of having a pregnancy affected by a neural tube defect and are advised to take a higher dose of 5mg of folic acid each day until they're 12 weeks pregnant.