The Numerous Vitamin B12 Benefits for Men

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Vitamin B12 is a water-soluble vitamin that plays a number of highly important and specialized roles in the human body. Vitamin B12 contains cobalt; as such, Vitamin B12 in its various forms are often referred to as cobalamins, the active forms of Vitamin B12 in the human body. Vitamin B12 works together with two other vital nutrients to regulate the levels of homocysteine (an amino acid) in the blood.

This is highly important in the context of human health, as elevated homocysteine levels are associated with a variety of serious health conditions and diseases, including heart disease, stroke, and Alzheimer’s disease.

Like many other vitamins and minerals, studies surrounding the various effects of Vitamin B12 are wide-ranging and continue to develop and unfold. Although Vitamin B12 has been studied in a variety of areas important to human health, a number of important functions have already been recognized and extensively studied.

What are the Vitamin B12 Benefits?

Vitamin B12 is a water-soluble vitamin that plays a number of important roles in the human body. For this reason, Vitamin B12 is irreplaceable in the human diet. While the benefits of Vitamin B12 are complex and wide-ranging, its foremost roles are in the nervous system and formation of red blood cells.

Nervous system

While Vitamin B12 plays a large number of important roles in the human body, it is notable for its role in the development and maintenance of a healthy, function nervous system. Accordingly, severe B12 deficiency can present with numbness, tingling, and nerve damage, as B12 plays an important role in the development of neurotransmitters. For this reason, Vitamin B12 has also been studied for its role in disorders of the nervous system, including Alzheimer’s disease, Parkinson’s disease, and dementia.

Blood-cell formation

Vitamin B12 is important for the formation of red blood cells, which are tasked with carrying oxygen to the body’s various organs and tissues. Accordingly, a deficiency of Vitamin B12 can lead to a serious form of anemia known as Vitamin B12 Deficiency Anemia.

Vitamin B12 Deficiency Anemia should not be confused with Pernicious Anemia, although the two are related. Pernicious Anemia is an autoimmune disorder that causes poor absorption of B12, while Vitamin B12 Deficiency Anemia presents due to other causes not associated with immune function.


A deficiency of Vitamin B12 often presents with constipation or other digestive abnormalities, although this is not due to B12’s role in digestion. However, pernicious anemia (which arises in response to a B12 deficiency) often presents with various digestive issues and symptoms, including nausea, vomiting, upset stomach, diarrhea, or loss of appetite.

This may be related to the digestive abnormalities associated with the development of anemia, which often includes disorders of malabsorption, such as Crohn’s disease or Celiac disease. Given that these conditions are associated with damage to the gastrointestinal tract, digestive abnormalities are common.

Brain Function

Vitamin B12 plays a critical role in neurological function. For this reason, B12 has been studied in various nervous system disorders and diseases of decline, including dementia. In the instance of a true B12 deficiency, an array of serious neurological complications can present, including numbness, tingling, confusion, issues of memory and concentration, depression, and anxiety.

While the associations between diseases of decline (such as dementia) remain unclear, some studies have suggested that an untreated B12 deficiency may cause elevated levels of homocysteine, and reduced levels of substances necessary to metabolize neurotransmitters.


Given the role of B12 in neurological health and function, it’s not terribly surprising that a deficiency in Vitamin B12 cause or increase symptoms of anxiety and depression. While a B12 deficiency is rarely the sole cause of anxiety and/or depression, it can certainly be a contributing or confounding factor.

In any instance, treating a B12 deficiency with supplementation when appropriate has been shown to alleviate mood-related symptoms. It’s worth noting, however, that the largest benefit of B12 supplementation is in the context of long-term treatment, rather than the period of initial supplementation.

Are There Vitamin B12 Benefits for Men?

While Vitamin B12 supplements have been promoted to enhance sperm concentration, sperm motility, and libido, studies have not shown an association between B12 and an enhanced effect on sexual function or fertility. The prevention of premature ejaculation has also not shown any relevance in the scientific literature.

Are There Vitamin B12 Benefits For Weight Loss?

Vitamin B12 supplements have become somewhat popular in the weight loss world in the form of multivitamins, nutrition shakes and concentrated B12 supplements. B12 injections are also offered as a supposed weight loss aid in many weight loss clinics, with proponents stating that B12 injections increase energy and metabolism, enhancing your ability to exercise and burn more Calories throughout the day through sheer metabolic influence.

Often used in combination with other B-Vitamins as a “metabolism enhancing” formula, it will likely come as a surprise to many consumers that Vitamin B12 supplements and injections have not been shown to enhance weight loss efforts in clinical studies.

So why is B12 often touted for its metabolism enhancing properties?

Stay with us here, because it gets a little complicated. B12 is often marketed as a weight loss enhancing supplement because of the well-recognized role of B12 in cellular metabolism. This is not to be confused with energy metabolism and energy needs; rather, B12 plays a vital role in the metabolism of fats and proteins in the human body, for example, the metabolism of amino acid homocysteine.

Marketers and supplement manufacturers understand that the word “metabolism” instantly brings with it the connotation of energy metabolism and weight loss, and the lack of FDA regulation in the supplement industry leaves many consumers to prey to marketing ploys and scientific distortion.

While B12 has many benefits, which are discussed in this article, weight loss is-alas- not one of them.

The Dangers of Vitamin B12 Deficiency

A deficiency of Vitamin B12 is rare, but can occur and is potentially very dangerous. Certain groups are at greater risk for B12 deficiency, including vegetarians, vegans, and individuals at risk for malabsorption. We will discuss the unique issues of B12 deficiency in vegetarian and vegan consumers below.

B12 deficiency can cause an array of serious symptoms and health issues, including megaloblastic anemia, weakness and undue fatigue, loss of appetite, constipation, and unintended weight loss. When B12 deficiency becomes more severe, so to do symptoms. A severe B12 deficiency can result in neurological abnormalities, including depression, anxiety, confusion, and poor memory.

While B12 injections are not used for weight loss (as discussed above), B12 injections are a common and effective treatment for a B12 deficiency. B12 injections are used preferentially over supplements, as B12 injections are able to bypass the gut, preventing the issue of malabsorption that may have caused a B12 deficiency in the first place.

Oftentimes, health conditions that cause trauma to the gastrointestinal tract (such as Crohn’s Disease or Celiac Disease) impair the ability of the body to adequately absorb various nutrients, including Vitamin B12.

Vegetarians and Vegans Must be Careful

Given the well-recognized health risks associated with a B12 deficiency (as discussed above), it’s especially important to note that certain groups- most notably, vegetarian and vegan consumers- are at an increased risk for a Vitamin B12 deficiency.

This is in large part because B12 is present most prominently in animal-based foods. Save for B12 supplements and some fortified breakfast cereals, B12 sources are strictly off limit to vegan consumers and very strict vegetarian consumers. Ovo-lacto-vegetarian consumers, for example, are not at as high a risk for Vitamin B12 deficiency due to their consumption of some animal products (eggs, milk, cheese, yogurt, etc).

Vegan consumers and stricter vegetarians, however, are more limited in their dietary choices with regards to animal foods. For this reason, B12 supplementation is often recommended for vegetarian consumers and should be considered essential for vegan consumers.

Food Sources of Vitamin B12

Vitamin B12 benefits

As noted above, B12 is readily available in natural animal-based food products. Supplementation, however, is likely necessary for vegan consumers and some vegetarian consumers, given the low availability of B12 in plant-based products.

Animal Products

Good sources of natural Vitamin B12 include (but are not limited to): clams, trout, salmon, liver, tuna beef, ground beef, haddock, milk, yogurt, cheese, ham, eggs, and chicken.

It’s worth noting that if you regularly consume animal-based products, including beef, chicken, fish, milk, eggs, or cheese, you are likely consuming enough Vitamin B12 to ensure healthy metabolic function. It’s also important to consider the overall healthfulness of any one food product, regardless of Vitamin B12 content.

While many animal foods are potent sources of Vitamin B12, some are healthier than others. Beef, for example, has the potential to be a healthy, protein-rich source of nutrition, but it also has the potential to be very high in saturated fat depending on cut, which is deleterious to cardiovascular health.

For this reason, always choose the healthiest, leanest sources of Vitamin B12 when possible, including Greek yogurt, low fat and nonfat dairy, eggs, lean ground beef, beef sirloin, beef tenderloin, chicken breast, salmon, trout, and tuna.

Fortified Foods

Some foods are fortified with Vitamin B12. Breakfast cereals are a common example of B12 fortification, as are certain nutrition products. However, depending primarily on fortified B12 products is typically less advantageous than focusing on sources of whole food nutrition.

Vitamin B12 Supplements

Like other dietary supplements, Vitamin B12 supplements are available in a variety of modalities.

However, it’s important to note that dietary supplements are not regulated by the Food and Drug Administration, as they are considered neither food nor drug. This leaves the dietary supplement industry to self-regulate, with recalls only issued when a series of harmful interactions become associated with any one product. Issues of purity and efficacy are a large issue in the supplement industry.

If you are planning on consuming a B12 supplement because of a diagnosed B12 deficiency, or because you are a vegan, vegetarian, or pregnant woman, always consult a doctor for their opinion on a higher-grade supplement, which may be prescribed depending on the unique condition and set of needs.


Multivitamins aside, B12 capsules are the most common form of B12 supplement purchased and consumed. Vitamin B12 capsules may interact with other medications or dietary supplements, so it’s always important to check with a doctor before self-prescribing a supplement or beginning a routine of supplementation. Side effects of B12 supplementation are rare but may include itching or upset stomach when taken without food.

Vitamin B12 Injections Benefits

Vitamin B12 injections are commonly touted as a weight loss aid. However, no clinical benefit has been shown in weight loss thanks to either B12 supplementation or injection. However, B12 injections are a commonly employed treatment for a Vitamin B12 deficiency, as this method allows absorption without traversing the gut, preventing the chance for malabsorption.

Should I take Vitamin B12 Supplements?

Maybe. While there are various benefits associated with Vitamin B12 consumption, lack of oversight and regulation of the supplement industry ultimately means that many dietary supplements lack potency or purity, or- conversely- may contain toxic levels of certain ingredients or Vitamins.

It’s also important to remember that dietary supplements can and do interact with other supplements and medications, so it’s always important to check with your doctor before beginning a regimen of supplementation.

However, for many consumers- including vegan, vegetarian, or otherwise plant-based eaters- supplementation may be helpful in the form of a high-quality multivitamin, prescribed supplement, or standard B12 supplement. For individuals with a diagnosed B12 deficiency, B12 injections administered by a physician may also be helpful.

Given the multitude of benefits of Vitamin B12 and the crucial roles in plays in the human body in the development and maintenance of a healthy nervous system and red blood cell production, it’s important to ensure that you’re consuming sufficient quantities of B12 rich foods.