Why Vitamin B12 Deficiency Causes Hair Loss and Grey Hair? - hair buddha
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Why Vitamin B12 Deficiency Causes Hair Loss and Grey Hair?

vitamin b12 deficiency


If you going grey early or losing large amounts of hair, chances are you may be lacking in this very important B vitamin – the B12.

Vitamin B12 is also called ‘the energy vitamin’ – because it helps your body to create energy from what you eat.

B12 also plays an important role in our hair growth and hair colour, but it’s kind of neglected in the hair area. If we have problems with our hair we think of all sorts of vitamins – A, E, C, D, or Biotin, but not B12.

What Happens if you Don’t Get enough B12

Hair loss or greying is just one of the symptoms of low B12. But this vitamin plays an important role in various body processes. Thus its lack can cause many other issues.

The trouble with B12 deficiency is that it can go unnoticed for several years. This is because the signs and symptoms are very subtle and vague, making it hard to detect. Also, since our body can store several years’ worth of B12, its lack often gets overlooked – making it a silent epidemic.

A few common signs and symptoms are:

  • lack of energy
  • extreme tiredness without any reason
  • becoming breathless
  • anaemia (pernicious)
  • tingling in the hands and feet
  • memory loss, brain fog, and cognitive decline
  • mood changes, irritability
  • depression, confusion, disorientation
  • sleep difficulties
  • dry skin
  • hair loss and/or premature greying
  • mouth ulcers

Why is Vitamin B12 so Important for our Health & Hair


Vitamin B12, also known by scientific name cobalamin, is one of the eight B vitamins.

Interestingly, vitamin B12 has the lowest daily requirement of all the B vitamins. It is needed in about 1/1000th the amount of some other B vitamins.

Despite the smallest requirement B12 is used by every cell in the body – from your DNA to how happy you feel. And of course it also helps maintains the hair colour and promotes hair growth.

Your body needs B12 for:

  1. making of red blood cells – which delivers oxygen to every cell in our body (including hair cell)
  2. healthy brain and nervous system function
  3. cell formation and longevity
  4. food digestion, absorption and iron use
  5. fat and protein metabolism (fat and protein molecules are broken down to create energy)
  6. healthy immune system function
  7. mood regulation, and reduce incidence of depression and anxiety
  8. memory function, concentration and mental clarity

Why Lack of B12 Causes Hair loss and Greying

To grow new hair the hair cells must constantly divide. And as we saw above B12 is required for making of every cell as well as its longevity. So a lack of B12 will cause hair growth to slow down a lot or in few cases even stop completely.

The good news is that once Vitamin B 12 levels come to normal, hair cells will be able to grow and replicate correctly, thereby leading to regrowth of previously lost hair.

How B12 deficiency turns hair Grey

Low levels of B12 can cause the homocysteine* levels to rise.

Elevated homocysteine is not good for our body as well as our hair.

This is because a high level of homocysteine is known to generate hydrogen peroxide – which literally bleaches and the hair from the inside out, turning your hair grey. (Raised homocysteine is also a risk factor for heart disease, Alzheimer, and stroke).

It seems that taking B12 supplements can lower homocysteine levels, and thus cause grey hair to darken and lost hair to regrow.

*Background on Homocysteine 

Methionine is an essential amino acid obtained from nuts, seeds, eggs and meat in the diet in the diet. Some methionine is turned into homocysteine. The body turns much of this homocysteine back into methionine with the help of vitamin B12. If someone is B12-deficient, homocysteine levels will increase because this reaction cannot take place. (source)

What Causes Vitamin B12 Deficiency

The most common cause is low intakes of B12. Vegans, and also vegetarians but to a lesser degree, are at risk for B12 deficiency.

This is because vitamin B12 is the only vitamin we can’t get from plants. It must be obtained from animal source: meat, eggs, dairy and fish.

But B12 deficiency can even occur in people who eat meat and consume dairy products. This is because vitamin B12 is a very large molecule and its absorption is complex and involves few steps – each of which can go wrong, making it difficult to absorb.

Here’s how B12 is absorbed…

Step 1: Normally, when you eat foods with vitamin B12, the stomach acids release vitamin B12 from the food

Step 2: B12 then combines with a special protein called intrinsic factor (made by cells in the stomach).

Step 3: The combined vitamin B12/intrinsic factor is then absorbed into the body further down the gut at the end of the small intestine.

The lack of B12 absorption usually results from:

  • Absent or low stomach acids (this will affect the release of B12 from food)
  • Atrophic gastritis, in which your stomach lining has thinned
  • Surgery that removed part of your stomach or small intestine, including weight loss surgery
  • Use of certain medications (antacids, metformin, anti-epileptic drugs)
  • Pernicious anaemia (your body destroys cells that make intrinsic factor)
  • Intestinal disorders such as celiac disease or crohn’s disease or other problems that make it difficult for your body to digest foods
  • Tapeworm infection
  • Excessive alcohol intake
  • Exposure to nitrous oxide (laughing gas)

Best Foods for Vitamin B12

Top Food Sources of Vitamin B12

Plants do not make B12. It is made by certain bacteria that live in the gut of animals.

Vitamin B12 is also made by soil microorganisms. So when herbivorous animals (such as goat and sheep) eat grass they then become a source of B12.

Besides, vegetables or herbs that are not washed properly may contain remnants of B12 from the bacteria present in the soil. (Eating vegetables without giving them a good wash was not a problem few years ago when the soil was not contaminated with pesticides. I wouldn’t eat them now, even if it is organic.)

Animal food sources of B12:

You can get your supply of B12 by eating fish, shellfish (prawns), red meat, poultry and eggs.

Dairy products – milk, cheese, yoghurt, paneer – are another way to get vitamin B12.

(Here’s a chart giving out how much of these foods you need to eat to get enough B12)

Plant Food Sources of B12:

I said above that plants do not make vitamin B12. But fermented plants may contain vitamin B12. Because bacteria produce vitamin B12 and fermented foods are fermented using bacteria, there are many rumours about vitamin B12 being in fermented foods.

Eating foods such as pickles, sauerkraut, khimchi and fermented soyabean may provide you with some amount of B12. Also you need to make sure that these foods are not pasteurized, as pasteurisation can kill good bacteria.

Certain seaweeds and algae such as Chlorella are also considered as source of vitamin B12.

Note: From all the research articles I read, plant foods are considered non-reliable source of B12. It is highly debated topic amongst the vegans and needs more studies to prove the point.

Tip: eating a diet rich in probiotics can help absorb B12 and other vitamins better from the foods you eat. I get my daily dose of probiotics from homemade yoghurt. And I sometimes take these probiotic supplements.

How do you know you have a B12 Deficiency?

B 12 deficiency is far more widespread than previously believed. Figures from this Framingham study suggest that nearly 40 percent of the United States population may be lacking in vitamin B12. Rates may be much higher in Africa, India, and Central and South America.

Like I said before, the signs and symptoms are very vague. So if you think you have B12 deficiency, the first step is to get a blood test done.

The next step is to find out the cause of the deficiency. Your doctor will help you do that.

If you have recently turned vegan/vegetarian there are good chances that you have enough B12 in your body. Unlike other water-soluble vitamins* (C and B vitamins), B12 doesn’t exit our body quickly in urine. It is stored in your liver, kidneys and other body tissues. So, people who completely give up animal products may go for years before showing any signs and symptoms of a B12 deficiency.

But if you are a long-term vegan and you have few of the symptoms of B12 deficiency then you may want to get yourself checked. Same holds true for vegetarians who don’t eat enough dairy products or eggs to meet their B12 needs.

*Water soluble vitamin: A vitamin that can dissolve in water. Water-soluble vitamins (such as vitamin C and B complex) are carried to the body’s tissues but are not stored in the body. So they must be taken in daily. But vitamin B12 is an exception, and it gets stored for several years.

What is a low B12 level?

B12 is measured with different units in different countries. And it might confuse people and some may think their levels are low. Plus, the normal range may also vary from country to country. So it’s best to consult your doctor, who will determine whether your levels are low or not.

As a general guide, B12 levels should be 191 ng/L or more. (191ng/L is equal to 550 pg/mL or 430 pmol/L approximately)

If your vitamin B12 levels are less than this, you can be considered B12 deficient.

B12 Supplements: What is Good?

Vitamin B12 Pill1

With all the problems that lack of B12 can bring, the treatment is pretty simple. You just replenish the levels back to normal and you will feel immediate improvement in your moods and overall energy. Hair loss or graying will take a few months to reverse. And so will brain and nerve function. (But, it is possible that nerve cell damage may be permanent).

Most of us can prevent vitamin B12 deficiency by eating enough meat, poultry, seafood, dairy products, and eggs. If you don’t eat animal products or you have a medical condition that limits how well your body absorbs nutrients, it’s important to take B12-supplements.

Some of the ways you can take B12:

  • injection
  • pill
  • sublingual lozenges
  • spray
  • eating fortified foods

Your doctor will decide the treatment option depending on things like your age, the diet you follow, and your medical condition.

Injections vs Pills:

If the B12 deficiency is not due to diet, the classic treatment is injection— of vitamin B12 in the form of hydroxocobalamin or or methylcobalamin. Initially injections are given twice a week for 3–4 weeks then every few months for the rest of the patient’s life. Some recent studies have suggested that high oral dose (2000mcg) may be as effective as injections for those with B12 malabsorption problems.

People who have B12 deficiency due to diet can be supplemented via a pill. An oral dose of 500 to 1000 mcg is usually prescribed, initially daily and thereafter weekly. You can also take a daily supplement providing 25 mcg of B12.

Note: These doses are a rough indicator of what to expect, however they will vary depending on age and level of deficiency.

When taking a B12 supplements, here are some suggestions:

  • Make sure methylcobalamin and Not cyanocobalamin is the active ingredient. Methylcobalamin is more readily absorbed and superior to other forms of B12.
  • Sublingual lozenges (that dissolves under the tongue), are thought to be better absorbed that conventional oral route.
  •  You can also get B12 in spray form. You spray on your mouth where it directly enters the blood stream.

To sum up:

  1. B12 is important for many life process such as making of red blood cells, DNA replication, digestion, mood regulation, brain health and hair health too.
  2. It’s mainly found in animal foods, so if you are a vegan or vegetarian consider getting yourself checked.
  3. B12 deficiency can be easily treated
  4. The good news is once the B12 levels are corrected you will see an immediate improvement in your energy and moods.
  5. Brain and nerve function will take some time to improve.
  6. And your hair too will take few months to recover.
  7. Many people taking B12 supplements have found reversal of greying and hair loss.

Do you take vitamin B12? Has it made any difference in your hair/health? Please share your experiences below!


Ting RZ, Szeto CC, Chan MH, Ma KK, Chow KM. Risk Factors of Vitamin B12 Deficiency in Patients Receiving Metformin. Archives of Internal Medicine. 2006;166(18):1975-1979.

Wood JM , Decker H, Hartmann H, Chavan B,  Rokos H,  et al. Senile hair graying: H2O2-mediated oxidative stress affects human hair colour by blunting methionine sulfoxide repair. The FASEB Journal. 2009;  23(7): 2065-2075.

Dali-Youcef N, Andrès E. An update on cobalamin deficiency in adult. QJM. 2009; 102 (1): 17-28.

Kwak CS, Lee MS, Lee HJ, Whang JY, Park SC. Dietary source of vitamin B12intake and vitamin B12 status in female elderly Koreans aged 85 and older living in rural area. Nutrition Research and Practice. 2010;4(3):229-234.

National Institutes of Health. Vitamin B12. NIH Fact Sheet.


  • Trisha says:

    Thanks for sharing this info, I have B12 deficiency and you are right it was detected too late, didn’t realize it affected my hair as well. I have started taking supplements was relived to know that it will help my hair fall. Thanks again for this well researched information

    • Rea says:

      After this nightmare winter, I thought it was stress, because became whiter and started falling out.
      I am going to make every effort to change this, starting today. Thanks!

  • […] More on vitamin B12 and how to correct the deficiency here. […]

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  • […] B12 deficiency is common in people who follow a vegan or vegetarian diet. The best food source of B12 is dairy products, egg, fish and meat. But B12 is also said to be found in fermented foods such as yogurt, kefir, homemade pickles, sauerkraut (see why B12 deficiency may cause hair loss) […]

  • Jennie says:

    Please help. My hair has always been my pride and joy. I figured since it is pretty damn healthy, it could deal with some bleach damage. And I figured the master stylist who did all the color-corrections would know how much would be too much. I was wrong, and now I want to burst into tears every time I look at my hair or touch it. I just don’t know what to do. my hair has also NEVER been shorter than this and it breaks and falls out. What should i do to regrow hair?

  • Trish says:

    Hi. I just wanted to let you know that a great vegan source that has a high content of B12 is nutritional yeast. It also contains other b vitamins as well.

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