Magnesium and B vitamins—what are the benefits of taking them together?

There are eight different B vitamins, all of which contribute to a healthy body. Magnesium, meanwhile, strengthens bones, aids the nervous system and helps in the synthesis of proteins, among other things.

In this guide, we explain:

  • the reasons for taking magnesium and vitamin B together
  • the benefits of both magnesium and vitamin B
  • the recommended daily intake
  • the causes and signs of vitamin B deficiency

Click on a link below to jump to the relevant section:

What are B vitamins?

Vitamin B isn’t one vitamin but eight different ones. Each B vitamin has a number and name, but some are better known by their number or their name, rather than both.

  • Vitamin B1
  • Vitamin B2
  • Vitamin B3 (known as niacin)
  • Vitamin B5 (known as pantothenic acid)
  • Vitamin B6
  • Vitamin B7 (known as biotin)
  • Vitamin B9 (known as folate/folic acid)
  • Vitamin B12

With most of these B vitamins, your intake relies on the foods you eat and any supplements you take, as your body doesn’t produce them naturally.

All eight B vitamins play their own role in supporting your metabolism, enabling your body to produce energy and generally keeping you in good health. But they have other benefits too, as we explain
further down the page.

B-complex vitamins

B-complex supplements make it easier for you to manage your vitamin B intake, by combining all eight B vitamins into a single tablet.

B vitamins are water soluble, which means they dissolve in water. Because of this, your body is unable to store them—as it does with minerals and fat soluble vitamins such as vitamin D and vitamin A—and so needs to replenish its supply each day.

Some B-complex supplements contain your full recommended daily allowance (RDA) of each B vitamin, while others provide even higher doses. See How much vitamin B should you take? below.

Can I take magnesium and vitamin B together?

Yes, as B vitamins and magnesium don’t compete for absorption inside your body. Indeed, many supplements combine them as a way of simplifying how you monitor your intake.

Vitamin B and magnesium work in tandem to:

  • promote normal function of the nervous system and normal psychological function
  • contribute to energy yielding metabolism
  • reduce tiredness and fatigue

Some people take vitamin B6 with magnesium to ease mood swings that occur with pre-menstrual syndrome (PMS).

Cobalt is a major part of vitamin B12, so if you get enough vitamin B12, you’ll also get enough cobalt. Taking magnesium helps your body to absorb and use minerals such as calcium, phosphorus and potassium.

What are the benefits of taking magnesium and B vitamins at the same time?

It’s much simpler! Many people have busy lifestyles with lots of distractions and don’t always have the time to keep close tabs on their vitamin and mineral intake. Taking magnesium and B vitamins at the same time, as part of a regular and straightforward daily routine, means there’s less chance of developing a deficiency later.

How do magnesium and B vitamins benefit the body?

Magnesium

Your body needs a number of minerals and vitamins to remain healthy and function in the proper way. Magnesium is one of them, benefiting your body by:

Having low levels of magnesium can significantly affect your sleep and cause you to feel fatigued.

B vitamins

Generally, every one of the B vitamins is important to your metabolism, as, together, they help your body break down food and convert it into energy. As a result, they reduce tiredness and fatigue and allow the parts of your brain that facilitate concentration, learning and memory to function properly.

The table below shows the main benefits of each B vitamin.

B vitamin

Benefits

B1 (thiamine)

Helps organs (such as the brain and heart) to develop and function properly

B2 (riboflavin)

Helps the body absorb and break down fats and acts as an antioxidant

B3 (niacin)

Keeps skin healthy, helps with digestion and can lower cholesterol levels

B5 (pantothenic acid)

Vital for the health of the brain and nervous system

B6 (pyridoxine)

Helps:

  • produce insulin
  • fight infection
  • create serotonin and dopamine, two neurotransmitters that regulate our emotions and mood

B7 (biotin)

Important for healthy hair and fingernails, and enables nerves to function properly

B9 (folate/folic acid)

Helps pregnant women reduce the risk of foetal deformities

B12 (cobalamin)

Helps:

  • create new red blood cells
  • keep nerve cells healthy
  • prevent pernicious anaemia

See Vitamin B12—benefits below

Vitamin B12—benefits

Vitamin B12 is arguably the most important of the B vitamins, due to its many health benefits.

  • It fights fatigue

B12 helps your body produce new red blood cells. These cells carry oxygen around your body, delivering it to your brain, lungs, muscles and tissues. When your system isn’t getting enough oxygen this way, you begin to feel tired and fatigued.

  • It helps with digestion

B12 enables your body to convert fats, proteins and carbohydrates into energy. Without it, your body wouldn’t be able to process these important nutrients and get them into your bloodstream.

  • It can improve cognitive function

Your brain needs vitamin B12 to develop and function as it should. Supplementing B12 intake has been found to boost some people’s general mood and improve their cognitive performance.

The video below, produced by BetterYou, explains why our bodies need vitamin B12.

Your magnesium and vitamin B intake

Eating a varied, balanced diet means you’ll be getting plenty of the magnesium your body needs to be healthy. However, as food sources don’t always provide the full daily recommended amount, you can increase your intake with supplements.

Some foods that are particularly rich in magnesium include:

  • brown rice
  • seafood
  • dark green vegetables (e.g. spinach)
  • legumes (e.g. lentils, split peas, tofu)
  • beans (e.g. black, kidney, edamame)
  • nuts (e.g. almonds, cashews, brazil nuts)
  • seeds (e.g. sunflower, sesame, pumpkin)
  • buckwheat
  • wholegrain cereals

As with magnesium, your vitamin B intake comes mainly from food—your body can produce biotin (B7) naturally, but none of the other seven vitamins. The table below tells you which foods to include in your daily diet to keep your intake of B vitamins at healthy levels.

B vitamin

Food sources

B1 (thiamine)

B2 (riboflavin)

  • Red meat
  • Poultry
  • Eggs
  • Milk and dairy products
  • Vegetables (asparagus, peas, mushrooms, broccoli, Brussels sprouts, spinach)
  • Wholegrain bread

B3 (niacin)

  • Red meat
  • Chicken
  • Oily fish (salmon, mackerel)
  • Eggs
  • Milk and dairy products
  • Potatoes
  • Fortified foods (breakfast cereals, plant milk)

B5 (pantothenic acid)

  • Red meat
  • Poultry
  • Fish
  • Milk and dairy products
  • Vegetables (mushrooms, broccoli, cauliflower, kale)
  • Peanuts
  • Wholegrains

B6 (pyridoxine)

  • Poultry
  • Fish
  • Milk and dairy products
  • Eggs
  • Vegetables (carrots, spinach, sweet potatoes)
  • Peanuts
  • Wholegrains

B7 (biotin)

  • Organ meats (liver, kidney)
  • Salmon
  • Egg yolk
  • Nuts and seeds
  • Yeast

B9 (folate/folic acid)

  • Vegetables (broccoli, Brussels sprouts, cabbage, spinach, asparagus, peas)
  • Fruits (bananas, oranges)
  • Chickpeas
  • Wholegrains

B12 (cobalamin)

  • Red meat
  • Chicken
  • Fish
  • Eggs
  • Dairy products
  • Fortified foods (breakfast cereals)

However, you may struggle to get enough B12 via your diet as the large size of its molecules makes it difficult for your digestive system to absorb the vitamin. Additionally, feeling tired, suffering with ill health or having a poor diet can also affect how well your body breaks down B12 and moves it into your bloodstream.

For this reason, it might be more beneficial to use a supplement. At BetterYou, we’ve produced a B12 oral spray. Spray it directly into your inner cheek and let it go to work. B12 tablets and capsules can be hard for your body to process, but in spray form the small droplets of B12 enter your system immediately.

How much magnesium should you take?

Adults (people aged 19–64) should take no more than 300 mg of magnesium per day. Children are advised to take lower dosages—exactly how much depends on how old they are. Click here to read more about recommended dosages.

However, these guidelines only apply to oral supplements such as tablets and capsules. Transdermal magnesium supplements (those you apply directly to your skin) have no upper limit, and are safe to use in whatever dosage you prefer.

How much vitamin B should you take?

Each of the eight B vitamins has its own recommended daily dosage, which differs depending on factors such as:

  • your gender
  • your age
  • your diet—i.e. if you’re vegan or vegetarian
  • (for women) whether you’re pregnant

Recommended daily dosages

The recommended daily dosages, as set by Public Health England, are as follows:

Adults

B vitamin

Recommended daily dosage

(mg = milligrams   mcg = micrograms)

Men

Women

19–64

65–74

75+

19–64

65–74

75+

B1 (thiamine)

1.0 mg

0.9 mg

0.9 mg

0.8 mg

0.8 mg

0.7 mg

B2 (riboflavin)

1.3 mg

1.1 mg

B3 (niacin)

16.5 mg

15.5 mg

15.1 mg

13.2 mg

12.6 mg

12.1 mg

B5 (pantothenic acid)*

B6 (pyridoxine)

1.4 mg

1.2 mg

B7 (biotin)*

B9 (folate/folic acid)

200 mcg

200 mcg

B12 (cobalamin)

1.5 mg

1.5 mg

Children (age 7–18)

B vitamin

Recommended daily dosage

(mg = milligrams      mcg = micrograms)

Male

Female

7–10

11–14

15–18

7–10

11–14

15–18

B1 (thiamine)

0.7 mg

1.0 mg

1.0 mg

0.7 mg

0.8 mg

0.8 mg

B2 (riboflavin)

1.0 mg

1.2 mg

1.3 mg

1.0 mg

1.1 mg

1.1 mg

B3 (niacin)

12.0 mg

16.5 mg

16.5 mg

11.2 mg

13.2 mg

13.2 mg

B5 (pantothenic acid)*

B6 (pyridoxine)

1.0 mg

1.2 mg

1.5 mg

1.0 mg

1.0 mg

1.2 mg

B7 (biotin)*

B9 (folate/folic acid)

150 mcg

200 mcg

200 mcg

150 mcg

200 mcg

200 mcg

B12 (cobalamin)

1.0 mg

1.2 mg

1.5 mg

1.0 mg

1.2 mg

1.5 mg

Children (age 1–6)

B vitamin

Recommended daily dosage

(mg = milligrams      mcg = micrograms)

Male

Female

1

2–3

4–6

1

2–3

4–6

B1 (thiamine)

0.3 mg

0.4 mg

0.6 mg

0.3 mg

0.4 mg

0.6 mg

B2 (riboflavin)

0.6 mg

0.6 mg

0.8 mg

0.6 mg

0.6 mg

0.8 mg

B3 (niacin)

5.0 mg

7.2 mg

9.8 mg

4.7 mg

6.6 mg

9.1 mg

B5 (pantothenic acid)*

B6 (pyridoxine)

0.7 mg

0.7 mg

0.9 mg

0.7 mg

0.7 mg

0.9 mg

B7 (biotin)*

B9 (folate/folic acid)

70 mcg

70 mcg

100 mcg

70 mcg

70 mcg

100 mcg

B12 (cobalamin)

0.5 mg

0.5 mg

0.8 mg

0.5 mg

0.5 mg

0.8 mg

*Pantothenic acid and biotin are found in many foods, so as long as you eat a varied and balanced diet you should get all you need.

Supplements—maximum recommended dosages

If you take vitamin B oral supplements (B-complex supplements, for instance), it’s important to know the maximum recommended dosage, as some supplements provide more than your full recommended daily allowance (RDA).

In most cases, taking more than the maximum dosage might be harmful to your health, although there isn’t a great deal of evidence to say exactly how.

The table below shows the maximum recommended dosages for each of the B vitamins.

B vitamin

Maximum recommended dosage

B1 (thiamine)

100 mg

B2 (riboflavin)

40 mg

B3 (niacin)

17 mg

B5 (pantothenic acid)

200 mg

B6 (pyridoxine)

200 mg

B7 (biotin)

0.9 mg

B9 (folate/folic acid)

1 mg

B12 (cobalamin)

2 mg

Who might take B vitamins?

While everyone requires the right amount of vitamin B to stay healthy, for certain groups of people, the need to maintain a proper vitamin B intake is particularly vital. These groups include the following:

Women who are pregnant or trying to conceive

If you’re pregnant, the standard recommendation is to take 400 micrograms of folic acid (vitamin B9) every day until you’re 12 weeks pregnant.

Ideally, you should begin taking folic acid supplements before you get pregnant—in other words, when you stop using contraception. Folic acid helps to prevent birth defects (e.g. spina bifida) in the foetus or baby.

Many pregnant women take a B-complex supplement, which provides the full recommended daily intake of all B vitamins and several other vitamins and minerals too.

Adults over the age of 60

Your body needs sufficient levels of stomach acid to be able to convert vitamin B12 from food into energy. As you get older, your stomach lining gradually becomes less able to produce this acid. If you’re over 60, this means you’re unlikely to be absorbing vitamin B12 as effectively as possible.

While taking oral B12 supplements can help, the tablet or capsule relies on the body being able to separate the vitamin from the proteins that bind it. Vitamin B12 mouth sprays (such as BetterYou’s Boost B12 Oral Spray), on the other hand, don’t need stomach acid to be absorbed.

It’s also common for adults over 60 to be deficient in vitamins B6 and B9 (folic acid) too, so supplementation is recommended with those also.

Vegans and vegetarians

Some of the best food sources of vitamin B12 include meat, eggs and dairy products. If you follow a vegan or strictly vegetarian diet, you’re at risk of becoming deficient in B12 if you don’t get enough of the vitamin through fortified foods or supplements.

Vitamin B12 comes in different forms, but look for supplements whose active ingredients include cyanocobalamin, methylcobalamin and adenosylcobalamin. BetterYou has developed a B12 spray aimed specifically at people who follow a vegan or strictly vegetarian diet—read more here.

People who take certain medication

If you’re prescribed a proton pump inhibitor (PPI) and take it regularly, you’re at higher risk of developing a vitamin B12 deficiency. This is because the medication lowers the rate at which your stomach produces its natural acids, which in turn can lessen its ability to absorb the vitamin.

Birth control pills can also deplete vitamins B6, B12, folate and riboflavin.

People who have digestive issues

Digestive disorders such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and coeliac disease can put sufferers at a higher risk of vitamin B12 deficiency. In these cases, it’s recommended to supplement B12 intake with an oral spray, which is absorbed by the blood vessels in the mouth rather than those within the stomach.

People with pernicious anaemia

Pernicious anaemia is the most common cause of vitamin B12 deficiency in the UK. The condition hampers your stomach’s ability to produce the intrinsic factor, a substance that helps your body absorb vitamin B12.

Although people who suffer with pernicious anaemia are usually prescribed a course of vitamin B12 injections, this is sometimes not enough to relieve the symptoms of deficiency completely. In those cases, boosting vitamin B12 intake with supplements might be recommended.

Read more about pernicious anaemia and vitamin B12 here.

What causes a vitamin B deficiency?

As B vitamins are found in many foods, following a well-rounded diet means you’re unlikely to develop any nutrient deficiencies. However, they are water soluble vitamins—meaning the body can’t accumulate reserves of them—and so you do need to replace them on a daily basis.

Some, like biotin (B7) and pantothenic acid (B5), you only need in small amounts, and providing you’re eating a balanced diet it’s difficult not to get enough.

Vitamin B12 is different, as it’s extremely difficult for your digestive system to absorb. It’s stored in the liver, and a B12 deficiency tends to develop over many years. Some symptoms of B12 deficiency include:

  • fatigue
  • memory problems
  • pins and needles in the hands and feet
  • an unsteady walk
  • feeling weak or faint
  • a pale yellow tinge to your skin
  • a sore red tongue

A B12 deficiency is commonly due to:

  • not getting enough through food
  • being unable to absorb it adequately
  • a medical condition (such as pernicious anaemia)

Related content

Magnesium supplements—are they safe and what dosage should you take?

Could you be at risk of vitamin B12 deficiency?

Using oral sprays to treat pernicious anaemia

Return to The Health Hub