Vitamin B-12 (Cobalamin; Cyanocobalamin)

Vitamin B12 is an essential vitamin. This means that the body requires vitamin B12 to work properly. Vitamin B12 can be found in foods such as meat, fish, and dairy products. It can also be made in a laboratory. It is often taken in combination with other B vitamins.

Vitamin B12 is taken by mouth to treat and prevent vitamin B12 deficiency, a condition in which vitamin B12 levels in the blood are too low.

Vitamin B12 is also taken by mouth for memory loss, Alzheimer's disease, to slow aging, and to boost mood, energy, concentration, mental function, and the immune system. It is also used for heart disease, clogged arteries and decreasing the risk of re-clogging arteries after surgery, high triglyceride levels, lowering high homocysteine levels (which may contribute to heart disease), male infertility, diabetes, diabetic nerve damage, nerve damage in the hands or feet, sleep disorders, depression, mental disorders, schizophrenia, weak bones (osteoporosis), swollen tendons, AIDS, inflammatory bowel disease, diarrhea, asthma, allergies, a skin disease called vitiligo, and skin infections.

Some people use vitamin B12 by mouth for amyotrophic lateral sclerosis (Lou Gehrig's disease), multiple sclerosis, preventing the eye disease age-related macular degeneration (AMD), a condition in which the body products too much thyroid hormone, Lyme disease and gum disease. It is also used by mouth for respiratory tract infections, maintaining fertility, ringing in the ears, bleeding, liver and kidney disease, canker sores, preventing fractures, preventing stroke, preventing blood clots, and for protection against the poisons and allergens in tobacco smoke. It is also taken by mouth to prevent cancer, including breast cancer, cervical cancer, colorectal cancer, and lung cancer.

Vitamin B12 is applied to the skin either alone or in combination with avocado oil for psoriasis and eczema. Also, a vitamin B12 nasal gel is applied for pernicious anemia and preventing and treating vitamin B12 deficiency.

Vitamin B12 is injected into the body for pernicious anemia, to prevent and treat vitamin B12 deficiency, and to prevent and treat a nervous system disorder called myelopathy, which can occur in people who are vitamin B12 deficient. It is also used for tremors, to treat Imerslund-Grasbeck disease, cyanide poisoning, nerve damage caused by shingles, diabetic nerve damage, tiredness or fatigue, chronic fatigue syndrome, hepatitis C, a condition in which the body products too much thyroid hormone, bleeding, cancer, psoriasis, and liver and kidney disease. It is also injected in the body to prevent arteries from re-clogging after surgery.

How does it work?
Vitamin B12 is required for the proper function and development of the brain, nerves, blood cells, and many other parts of the body.

Inherited Vitamin B12 deficiency (Imerslund-Grasbeck disease).
Vitamin B12 deficiency.
Cyanide poisoning.
High level of homocysteine in the blood (Hyperhomocysteinemia)
An eye disease called age-related macular degeneration (AMD).
Nerve damage from shingles.

Adults

By Mouth:

The typical general supplemental dose of vitamin B12 is 1-25 mcg per day: The recommended dietary allowances (RDAs) of vitamin B12 are: 1.8 mcg; older children and adults, 2.4 mcg; pregnant women, 2.6 mcg; and breast-feeding women, 2.8 mcg. Because 10% to 30% of older people do not absorb food-bound vitamin B12 efficiently, those over 50 years should meet the RDA by eating foods fortified with B12 or by taking a vitamin B12 supplement. Supplementation of 25-100 mcg per day has been used to maintain vitamin B12 levels in older people.

For vitamin B12 deficiency: Vitamin B12 doses of 300-10,000 mcg daily have been used. However, some evidence suggests that the most effective oral dose is between 647-1032 mcg daily.

For high blood levels of homocysteine: Vitamin B12 doses of 400-500 mcg in combination with 0.54-5 mg of folic acid and 16.5 mg of pyridoxine has been used.

For preventing age-related macular degeneration (AMD): A combination of 1 mg of vitamin B12, 2.5 mg of folic acid, and 50 mg of pyridoxine daily has been used for 7.3 years.

Applied to the Skin:

For atopic dermatitis (eczema): A specific vitamin B12 0.07% cream (Regividerm) applied twice daily has been used.

For psoriasis: A specific cream (Regividerm, Regeneratio Pharma AG, Wuppertal, Germany) containing avocado oil plus vitamin B12 0.7 mg/gram applied for 12 weeks twice daily has been used.

As an Injection:

For vitamin B12 deficiency: The usual dose is 30 mcg as an injection into the muscle or under the skin daily for 5-10 days.

For maintenance therapy, 100-200 mcg once monthly is commonly used. Both cyanocobalamin and hydroxocobalamin forms are used.

The usual dose for pernicious anemia-associated vitamin B12 deficiency is 100 mcg given as an injection into the muscle or under the skin once daily for 6-7 days. Then the dose may be given every other day for 7 doses followed by every 3-4 days for around 3 weeks. Then, 100 mcg should be injected every month for life.

Another dosing recommendation for injectable vitamin B12 includes 1000 mcg daily for 7-10 days followed by 1000 mcg weekly for 1 month followed by 1000 mcg monthly for life.

For a hereditary condition that causes vitamin B12 malabsorption (Imerslund-Grasbeck disease): Vitamin B12 in the form of hydroxocobalamin has been injected into the muscle at a dose of 1 mg daily for 10 days followed by once monthly for the remainder of the person's life.

For cyanide poisoning:Hydroxocobalamin (Cyanokit) has been given intravenously (by IV) for a total dose of up to 10 grams.

Used in the Nose:

For vitamin B12 deficiency: Doses of 500 mcg of vitamin B12 have been injected into one nostril weekly.

Applied Under the Skin:

For nerve damage from shingles: As an injection under the skin, 1000 mcg of vitamin B12, with or without 100 mg of thiamine, has been given six times weekly for 4 weeks.

Children

By Mouth:

The recommended dietary allowances (RDAs) of vitamin B12 are: Infants 0-6 months, 0.4 mcg; infants 7-12 months, 0.5 mcg; children 1-3 years, 0.9 mcg; children 4-8 years, 1.2 mcg; children 9-13 years, and 1.8 mcg; older children.

As an Injection:

For vitamin B12 deficiency: Injecting 0.2 mcg/kg of vitamin B12 into the muscle or under the skin once daily for 2 days, followed by a 1000 mcg injection daily for 2-7 days and another 100 mcg injection weekly for 4 weeks thereafter has been used. Additional injections of 100 mcg monthly may be needed depending on level of symptom improvement and cause of vitamin B12 deficiency.

Vitamin B12 is SAFE for most people when taken by mouth, applied to the skin, taken through the nose, administered as a shot, or injected into the vein (by IV). Vitamin B12 is considered safe, even in large doses.

Mild itching has been reported in one person who used a specific avocado oil plus vitamin B12 cream for psoriasis.

Pregnancy and breast-feeding: Vitamin B12 is SAFE for pregnant or breast-feeding women when taken by mouth in the amounts recommended. The recommended amount for pregnant women is 2.6 mcg per day. Breast-feeding women should take no more than 2.8 mcg per day. Don't take larger amounts. The safety of larger amounts is unknown.

Post-surgical stent placement: Avoid using a combination of vitamin B12, folate, and vitamin B6 after receiving a coronary stent. This combination may increase the risk of blood vessel narrowing.

Allergy or sensitivity to cobalt or cobalamin: Do not use vitamin B12 if you have this condition.

Leber's disease, a hereditary eye disease: Do not take vitamin B12 if you have this disease. It can seriously harm the optic nerve, which might lead to blindness.

Abnormal red blood cells (megaloblastic anemia): Megaloblastic anemia is sometimes corrected by treatment with vitamin B12. However, this can have very serious side effects. Don't attempt vitamin B12 therapy without close supervision by your healthcare provider.

High numbers of red blood cells (polycythemia vera): The treatment of vitamin B12 deficiency can unmask the symptoms of polycythemia vera.