Vitamin B12 Deficiency: Symptoms and Supplementation

Summary

A vitamin B12 deficiency can cause anaemia and neurological complaints, such as fatigue, tingling and problems with movement. Possible causes include insufficient intake, a fully plant-based diet without fortified products or a supplement, and reduced absorption. Whether a deficiency is present only becomes clear through blood tests interpreted alongside your symptoms and medical history.

Table of Contents

You might see it in a headline on your phone, someone mentions it in passing, or you have been taking acid-suppressing medication for years: vitamin B12 often only comes into focus when something seems off. This article is for men who want to make sense of their symptoms, who eat plant-based, or who use medications long-term that may affect absorption. After reading it, you will know what vitamin B12 does in your body, which symptoms may point to a deficiency, how diet and absorption play a role, what a B12 value does and does not tell you, and where self-supplementation ends.

What does vitamin B12 do and what symptoms does a deficiency cause?

A vitamin B12 deficiency can manifest along two tracks: through anaemia and through the nervous system. This follows directly from the vitamin's functions. Vitamin B12, also called cobalamin, is a water-soluble vitamin that your body needs for the production of red blood cells and for the functioning of the nervous system. Your body can store vitamin B12, which explains why insufficient intake or absorption is not immediately noticeable: a deficiency can build up for a long time before symptoms appear.

The first track runs through your blood. With anaemia, fatigue, a weak feeling, rapid breathlessness during exertion, dizziness, heart palpitations, headaches and pallor may occur. These symptoms are not very specific: they fit a B12 deficiency, but also many other causes.

The second track runs through your nerves and forms its own category. Think of tingling in the hands and feet, reduced sensation in your fingers or feet, the feeling of walking on cotton wool, less precise movements, problems with movement and balance problems. The distinction between the two groups is practically useful, because the first group is mainly about your energy and breathing, and the second about sensation and movement. Symptoms vary from person to person and can develop gradually, making it easy to attribute them to a busy schedule, poor sleep or getting older.

Itching, weight gain and hair loss do not belong to the two groups of symptoms typically associated with a B12 deficiency. Each has dozens of other possible causes and is not in itself evidence of a vitamin B12 deficiency.

What causes a B12 deficiency? Diet, absorption and medications

A B12 deficiency develops along two routes: you take in too little over a prolonged period, or your body absorbs the vitamin less effectively. Sometimes both occur at the same time.

The intake route is linked to your diet. Vitamin B12 occurs naturally only in animal products. Men who eat a fully plant-based diet are therefore at risk when they use neither fortified products nor a supplement. The Netherlands Nutrition Centre (Voedingscentrum) advises those following a fully plant-based diet not one or the other, but both: vitamin B12-fortified alternatives and, in addition, a vitamin B12 supplement. Even those who do not eat strictly vegan but have consumed few animal products for many years may consistently fall short of their needs.

The absorption route is less visible, because your diet may look perfectly fine while too little vitamin B12 is actually reaching your body. Gastrointestinal conditions can reduce absorption. In addition, long-term use of acid-suppressing medication (such as proton pump inhibitors) can increase the risk of a vitamin B12 deficiency. If you have been using other medications for a long time, that is something to factor in when your symptoms are assessed; which medications are specifically relevant depends on your situation.

Because your body stores vitamin B12, the underlying cause may have been present longer than the symptoms suggest. Switching to a plant-based diet or starting acid-suppressing medication years ago is therefore not a minor detail, but a relevant part of the picture.

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Multi-Botanical Vitamin Complex (CORTEX)

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Vitamin B12 in food and how much you need per day

For most men, food is the most important source of vitamin B12. Vitamin B12 occurs naturally in:

meat and meat products;
fish;
milk and dairy products;
eggs.

Plant-based products do not naturally contain vitamin B12. Some are fortified with it, such as certain dairy alternatives. If you eat plant-based, it is worth checking when shopping whether a product is fortified, as two seemingly similar drinks can differ on this point.

The recommended daily amount is 2.8 micrograms of vitamin B12 per day. This standard applies to all adults from the age of 18; there is no separate, higher or lower standard for men. What matters is what that figure does and does not mean. The recommended amount is a dietary standard, not a diagnostic threshold. If you fall short on a given day, you do not automatically have a deficiency, precisely because your body maintains a reserve. What matters is your intake over a longer period.

In practice, this means: those who eat a varied diet including animal products usually get their vitamin B12 from their regular meals. Those who eat fully plant-based need fortified products and a supplement to consistently meet their needs.

What does your B12 value tell you and when should you have a blood test?

A single B12 value does not in itself indicate whether you have a deficiency, what the cause is, or which treatment is appropriate. A result only gains meaning in the context of your symptoms, your diet, your medication use and your medical history. Laboratories also use their own reference ranges, and sometimes additional testing is needed. A low, high or borderline value is therefore a starting point, not a conclusion.

Your GP is the right person to assess the full picture. Your GP will first look at your symptoms and your situation, and can then request a blood test. Based on symptoms and results together, your GP determines whether a deficiency is present and which treatment is appropriate. When you have that conversation, make sure to mention whether you eat plant-based, how long you have been taking acid-suppressing medication or other medications if applicable, and whether you are already taking supplements.

Have your symptoms assessed if any of the following persist:

tingling;
loss of sensation;
balance problems;
fatigue without a clear explanation;
shortness of breath;
dizziness;
heart palpitations.

Neurological symptoms, or clear symptoms that may point to anaemia, are not a reason to keep trying with supplements on your own for an extended period. Starting high doses before any blood has been taken also makes it harder to determine afterwards what was going on.

B12 tablets, injections and the role of folate

A supplement, a tablet and an injection are not three variants of the same product. "Supplement" is the broad term for a product that tops up vitamins or other nutrients. A tablet is a form of administration: a way of taking vitamin B12 orally. An injection is a form of treatment that you do not buy yourself, but that is given within a medical context, in situations where it is necessary.

The biggest difference lies in the dosage and the purpose. For daily supplementation, the reference point is around 2.8 micrograms per day. For a confirmed deficiency, tablets of 1000 micrograms per day are used in certain situations. That is a treatment dose within a medical context, not a general dosage for healthy men. Whether tablets are sufficient or injections are needed depends on the cause: an absorption problem calls for a different approach than a diet with too few animal products. High doses, injections or prolonged treatment are therefore not something to start on your own.

Folate deserves a separate warning. Folate contributes to normal blood formation. Do not use folate independently to address a possible B12 deficiency: it must first be clear where the anaemia is coming from, because neurological symptoms can continue even while the blood picture improves.

When do you not need extra vitamin B12?

If you eat a varied diet with regular meat, fish, dairy or eggs, and you have no condition or medication affecting absorption, you will generally get your vitamin B12 through your regular diet. A supplement is then not a necessity. Taking in more than the recommended amount does not make the vitamin more useful; the recommended amount is a target to reach, not a minimum to far exceed.

A supplement is also not an explanation for symptoms. Someone who is tired and starts taking vitamin B12 is not thereby making a diagnosis. Fatigue has dozens of possible causes, and a supplement you choose yourself says nothing about which of those applies to you. With a confirmed deficiency, the same applies in reverse: a daily supplement in the order of the recommended amount is different from a treatment, which typically involves much higher doses or injections.

Where a supplement does make sense is when there is a clear reason in your diet or lifestyle: you eat fully plant-based, you consistently eat few animal products, or you want to secure your daily intake rather than leaving it dependent on what happened to be on the table that week. That is supplementation. Once persistent symptoms are present, it is time for assessment, not for a different product.

Vitamin B12 as part of a fixed morning formula

We do not make a standalone B12 product, and that is a deliberate choice. A treatment dose belongs with a treatment, not with a capsule you take next to your coffee every morning. What we do make is a morning formula in which vitamin B12 is one component of a broader composition, dosed as a daily foundation.

For the dosage, we chose 2.5 micrograms of vitamin B12 per capsule. That is 100% of the reference intake (RI), the European measure used for supplements. The Dutch recommendation of 2.8 micrograms is slightly above that; the difference comes from your regular diet. A higher dose would not make the formula better, only further removed from what a daily supplement should be.

For the form, we chose methylcobalamin. We mention that form because you should know what you are taking, not because we claim methylcobalamin works better than cyanocobalamin. We also determined the timing in advance: breakfast, because an intake tied to your first meal is the easiest to repeat every day.

CORTEX contains per daily dose of 1 capsule: vitamin B12 2.5 µg (100% RI) as methylcobalamin, vitamin B6 0.7 mg (50% RI) as pyridoxal-5'-phosphate, kelp extract 37.5 mg of which iodine 37.5 µg (25% RI), bacterial cultures 12 billion CFU from 9 strains, a prebiotic mix of 168.3 mg (acacia fibre, inulin), Cereboost™ American ginseng extract 100 mg, Spanish sage extract 50 mg, Bacopin® Bacopa monnieri extract 20 mg (of which bacosides 4 mg) and saffron extract 10 mg. Take 1 capsule per day with a glass of water, preferably at breakfast. Each pouch contains 30 capsules, enough for 30 days.

One capsule, one fixed morning moment, and your daily foundation is in place before the day begins.

From our formulas

Multi-Botanical Vitamin Complex (CORTEX)

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Frequently asked questions about vitamin B12

Can a vitamin B12 deficiency cause itching, hair loss or weight gain?

Itching, hair loss and weight gain are not in themselves evidence of a vitamin B12 deficiency. They do not belong to the two groups of symptoms typically associated with a deficiency: symptoms caused by anaemia and neurological symptoms. Each of these three also has many other possible causes, from skin conditions to lifestyle. You do not draw a conclusion about vitamin B12 from a single isolated symptom, but from the combination of symptoms, risk factors and blood tests.

Are B12 sublingual tablets different from regular B12 tablets?

A sublingual tablet dissolves in your mouth rather than being swallowed. The difference therefore lies in the form of administration, not in the vitamin itself. It has not been established that a sublingual tablet offers more to a healthy man than a regular tablet. More important than the form is the dosage and whether it concerns daily supplementation or a treatment.

Can you take in too much vitamin B12?

For daily use by healthy men, the recommended amount of 2.8 micrograms per day is the reference point. Doses of 1000 micrograms belong within a treatment for a confirmed deficiency and are not a daily standard. There is therefore no reason to go far above the recommended amount without cause. A high B12 value in your blood, like a low one, is a result that must be read in the context of your situation and is not a conclusion in itself.

Does the normal B12 value differ by age?

Tables with normal values by age circulate online, but laboratories use their own reference ranges and the meaning of a result depends on your situation. Placing a figure from such a table next to your own result therefore says little. For dietary intake, one fixed standard applies: 2.8 micrograms per day for every adult from the age of 18. That standard is about what you take in, not about what is measured in your blood.

What does cyanocobalamin on a B12 supplement mean?

Cyanocobalamin is one of the forms in which vitamin B12 appears in supplements; methylcobalamin is another. In both cases it is vitamin B12, and the number of micrograms per daily dose is the figure to use when comparing products. It has not been established that one form clearly works better than the other for a healthy man. When comparing, therefore, look first at the dosage and at what else is in the product.