If the body properly uses B12, studies show it can stay in the body for up to five years. Of course, the vitamin B12 shots themselves do not stay in the body for five years. The vitamin is more quickly absorbed when administered in injection format, but this is also what makes it so effective for weight loss.
Unlike most other vitamins, B12 is stored in substantial amounts, mainly in the liver, until it is needed by the body. If a person stops consuming the vitamin, the body's stores of this vitamin usually take about 3 to 5 years to exhaust.
How long does it take to recover from B12 deficiency? Once you begin treating your vitamin B12 deficiency, it can take up to six to 12 months to fully recover. It is also common to not experience any improvement during the first few months of treatment.
The recommended daily amount of vitamin B-12 for adults is 2.4 micrograms.
Vitamin B12 is a water soluble vitamin. That means your body tends to get rid of excess amounts of it through your urine. It doesn't build up in your body. However, side effects are still possible.
Vitamin B12 is a water-soluble vitamin, which means that excess amounts are flushed out of the body through the urine, making a vitamin B12 overdose nearly impossible. However, while vitamin B12 is safe when used as recommended, there are several vitamin B12 injection side effects to consider as well.
Disturbed or blurred vision can also occur as a result of a Vitamin B12 deficiency. This happens when the deficiency causes damage to the optic nerve that leads to your eyes. The nervous signal that travels from the eye to the brain is disturbed due to this damage, leading to impaired vision.
As summarized in the table provided, vitamin B12 (cobalamin) absorption and utilization by the body can be compromised with the chronic use of certain medications which include: colchicine, chloramphenicol, ethanol, histamine 2 receptor antagonists (H2RA), metformin, and proton pump inhibitors (PPI).
Vitamin B12 is a nutrient that helps keep your body's blood and nerve cells healthy and helps make DNA, the genetic material in all of your cells. Vitamin B12 also helps prevent megaloblastic anemia, a blood condition that makes people tired and weak.
Low levels of vitamin B-12 can be caused by: Diet. Vitamin B-12 is mainly found in meat, eggs and milk, so people who don't eat these types of foods may need to take B-12 supplements. Some foods have been fortified with B-12, including some breakfast cereals and some nutritional yeast products.
In some people, high levels of B12 may cause gastrointestinal problems such as bloating and diarrhea. And if you have high blood pressure or poor cardiovascular health, having too much B12 may further complicate these issues. Pregnant and breastfeeding women may also need to be especially mindful of B12 levels.
Vitamin B12 testing requires a blood sample, which is usually taken from your arm in a medical office, health clinic, hospital, or lab.
For the majority of people, I recommend once weekly for 4 weeks. Then B12 shots can be helpful monthly as maintenance. If we are treating autoimmunity or pernicious anemia, you will receive B12 weekly or twice weekly for 6-12 weeks.
There is no risk of an overdose when taking large amounts of vitamin B-12 such as 1000 mcg, because it is a water-soluble vitamin. Meaning the body will use the amount that it needs then the excess will be excreted through urine.
Gastrointestinal issues. A B12 deficiency may also cause diarrhea, nausea, constipation, bloating, gas, and other gastrointestinal symptoms ( 2 , 19 ). These issues can affect both adults and children ( 2 , 20 ).
Even though the RDA for vitamin B12 is 2.4 mcg for adults, you may take higher amounts since your body will only absorb what it needs and then excrete the rest . Like vitamin D, daily intake of vitamin B12 is important to ensure you are supplying your body with the nutrients it needs to function.
Vitamin B12 is an essential nutrient. Fish, shellfish, meat, eggs, and dairy products are good sources of vitamin B12. The amount that should be consumed on a daily basis is called the recommended dietary allowance (RDA). The RDA is 2.4 mcg daily for people 18 years and older.
 People who regularly take medications that suppress stomach acid for conditions like gastroesophageal reflux disease (GERD) or peptic ulcer disease—such as proton-pump inhibitors, H2 blockers, or other antacids—may have difficulty absorbing vitamin B12 from food.
Bananas also contain fibre and potassium. It helps manage blood pressure, reduce stress, and relieve constipation and ulcer problems. The fruit also helps regulate body temperature. Another fruit that is rich in vitamin B12 is blueberries.
B12 supplements are usually safe. For adults, doctors recommend 2.4 micrograms a day. If you take more than what you need, your body passes the rest out through your pee. Still, high doses could have some side effects, like dizziness, headache, anxiety, nausea, and vomiting.
Not getting enough vitamin B12 to the point of a deficiency can cause a variety of serious symptoms including depression, joint pain, and fatigue.
Mild vitamin B12 deficiency in otherwise healthy individuals can result from dietary patterns that result in insufficient dietary intake of animal source foods including strict vegetarian and vegan diets, or can be caused by changes in stomach function resulting from aging and/or pharmaceutical use .
Symptoms of Vitamin B Deficiencies
Vitamin B1 deficiency is often associated with alcoholism and may cause toxic optic neuropathy leading to blurred vision and a restricted visual field. Vitamin B2, B3, and B6 deficiencies are associated with dry eyes and eye infections in the front of the eye.
Elevated levels of serum cobalamin may be a sign of a serious, even life-threatening, disease. Hematologic disorders like chronic myelogeneous leukemia, promyelocytic leukemia, polycythemia vera and also the hypereosinophilic syndrome can result in elevated levels of cobalamin.