Even the lowest doses in B12 supplements are many times the recommended dietary allowance. Doses up to 1,000 mcg, though unnecessary, aren't harmful.
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.
For B12 deficiency, a typical injection dose is 1,000 mcg once a week for 4 to 8 weeks and then 1,000 mcg once a month. But dosages can vary depending on if you're treating severe, mild, or asymptomatic B12 deficiency.
Some provide doses of vitamin B12 that are much higher than recommended amounts, such as 500 mcg or 1,000 mcg, but your body absorbs only a small percentage of it. These doses are considered safe.
In the absence of a consensus on the threshold that defines an abnormal increased B12 level, elevated B12 is generally defined as a level higher than the upper limit of the reference range, i.e., around 1000 +/− 100 ng/L (738 +/− 73.8 pmol/L) [2,3,4].
It may take a few weeks before your vitamin B12 levels and symptoms (such as extreme tiredness or lack of energy) start to improve. If you have hydroxocobalamin injections to boost your vitamin B12 levels at the start of treatment, the cyanocobalamin tablets may start to work within a few days.
Vitamin B12, for example, should definitely be taken in the morning. This is because it is important for energy metabolism, which may interrupt your sleep if taken at night.
Ideal Vitamin B12 Dosage for Seniors
The exception is if you have underlying health conditions that impact how well your body absorbs vitamin B12 or if you have a severe deficiency. In some cases, high doses of 500 to 1000 micrograms per day might be necessary to reverse B12 deficiency. Again, talk to your doctor.
The National Institutes of Health (NIH) recommends a daily B12 allowance of 2.4 mcg (micrograms) for the average adult.
The recommended daily amount for B12 is 2.4 mcg for adults. Pregnant and lactating women need higher amounts [1]. There is no upper intake limit for vitamin B12 because there is no known toxicity [2]. Most vitamin B12 supplements provide a range of strengths between 500 to 5,000 mcg [2].
Vitamin B12 is an essential nutrient that helps the body create DNA, nourishes the brain and nervous system, and assists with the formation of healthy red blood cells. The nutrient occurs naturally in meat, fish, and dairy products, and can be created in a laboratory.
Vitamin C and vitamin B12 are water-soluble vitamins, which means you need water to absorb them. “Take water-soluble vitamins on an empty stomach with a glass of water,” recommends Dr. Perez-Gallardo.
Fat-soluble and water-soluble vitamins
For example, although it's safe to take vitamin D with vitamin B12, it's not advisable, says Virgilio Sanchez, MD, a board certified family medicine physician at Conviva Care Center in Miami, Florida.
Can you overdose on vitamin B12? Overdosing on vitamin B12 is unlikely. Because vitamin B12 (cobalamin) is a water-soluble vitamin and your body excretes it daily in your urine, it doesn't build up in the body like fat-soluble vitamins—like vitamin D—do.
People who are concerned about their low level of energy should be advised that unless they already suffer from a vitamin B12 deficiency, there is no strong evidence to support the notion that taking large doses of vitamin B12 will increase their energy levels.
Vitamin B12 is considered an important brain and nervous system micronutrient and is often used for anxiety. It helps to ensure normal function for your nerves, which can help combat physical symptoms of anxiety.
Since B12 shots are injected intramuscularly bypassing the digestive process, they start to work immediately. Typically, our patients experience positive effects between 24-72 hours after the treatment.
Lifelong vitamin B12 supplements may be required at doses between 100 and 1,000 micrograms. As such, "B12 vitamin 1,000 mcg" refers to a high dose (1,000 micrograms) of vitamin B12 suitable for someone with nutrient absorption issues or pernicious anemia.
Dosages for Older People
Around this age, you should be getting around 2.4 micrograms of B12 a day. Not only does this mean consciously eating foods that contain vitamin B12 but it also means that you should ingest this vitamin as a supplement. By taking supplements, you will ensure that your body absorbs vitamin B12.