Muscle Sport Magazine

Under the Spotlight: Vitamin B12

By Leigh Penman

Vitamin B12 has earned the reputation of being an energy booster and an appetite stimulant and, it is for this reason that many bodybuilders and athletes choose to supplement their diet with this nutrient. It can also be a worthy addition to post cycle treatment (PCT) since it is on discontinuing the use of anabolic agents that most athletes are likely to find their energy and appetite levels falling.

However, aside from its use in PCT, vitamin B12 has many valuable functions in the body, particularly when it comes to the formation of red blood cells and the maintenance of a healthy nervous system. Vitamin B12 assists normal growth and development, helps with certain types of nerve damage and treats pernicious anemia. Another important role of B12 is in the maintenance of the myelin sheath, which provides insulation in nerve cells. It is the deterioration of this valuable protective cover which results in the neurological damage seen in such conditions as Multiple Sclerosis.

Vitamin B12 is also essential when it comes to the production of blood platelets and red and white blood cells. In addition it participates in a variety of cellular reactions, which are vital when it comes to the liberation of energy from carbohydrates.


The absorption of Vitamin B12 depends on a substance known as gastric intrinsic factor (IF). Intrinsic factor is secreted by the stomach lining and it binds to B12 assisting its passage through the intestinal lining and into the blood. This can be one limiting factor when it comes to the full absorption of orally ingested B12. Any abnormal production of gastric intrinsic factor can reduce B12 uptake and therefore lead to deficiency.

A deficiency of Vitamin B12 can lead to symptoms such as fatigue, weakness, nausea, constipation, flatulence, loss of appetite and weight loss. However, when the deficiency state is severe, symptoms can progress to nervous system problems such as numbness and tingling in the hands and feet and, at its worst, destruction of the myelin sheath.

Since levels of Vitamin B12 often decrease with age (which may in part be due to a limiting factor present in its full absorption) it may be wise to consider one of the many forms of supplementation available. Any form of bacterial overgrowth in the stomach will also compromise the uptake and utilization of this valuable nutrient.


Vitamin B12 is found principally in animal products (e.g. liver, red meat, tuna, cottage cheese, yogurt and eggs). However, once again, due to the fact that absorption may be compromised in many ways, the use of a nutritional supplement containing B12 is often advised. The forms of B12 commonly used in such products are cyanocobalamin, hydroxocobalamin and the two coenzyme forms methylcobalamin and 5- deoxyadenosyclcobalamin.


Due to the array of limiting factors surrounding the absorption of orally administered Vitamin B12, many athletes choose to use the injectable form of this vitamin. I have even heard of it being mixed with injectable Winstrol by some bodybuilders. Either way, it is not surprising that physicians usually opt for the inject form when prescribing its use. Suffice to say that, if you are considering the use of Vitamin B12, perhaps the injectable form is the way to go.

Leigh Penman, in addition to be a staff writer at MuscleSport Mag, has been writing for bodybuilding magazines, websites and nutritional supplement companies since 1985. Whilst residing in the UK, she earned the reputation of being one of the top female writers in bodybuilding-related media. Her credits included being a contributing editor on all the magazines in production as well as filling the shoes of Ladies Editor and Showbiz Editor on two publications (the later being on Arnold’s sanctioned magazine, ‘Bodypower’). During this time she also competed successfully on four occasions (placing in the top four in all contests).

Relocating to New York in the late 1990s she focused her writing attention to crystal healing techniques and metaphysics – however, she still maintained a five day workout schedule during this time and gained her personal training certificate.

Having also studied pharmacology in relation to sports performance, her writing began taking her in that direction until the present day which sees her embarking on a return to the magazine world, as well as extending her web-related work in the bodybuilding and fitness field.

Leigh has been working out for close to thirty years so she is clearly a writer who ‘walks her talk.’
She can be contacted personally at or you can also check her out at New York’s favorite metaphysical store

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