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].
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.
Water soluble vitamins, like B12, can be tolerated at higher doses without adverse effects upon the body, and the National Academy of Medicine has not established an upper limit of Vitamin B12 intake.
Vitamin B12 has a low risk of causing harm, even at high doses. Because of this, there's currently no maximum dose that's widely recommended.
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.
High-dose vitamin B supplements should be avoided, because they can lead to nerve damage.
In fact, 5000 mcg of Vitamin B12 supplementation is a safe dosing amount. Although, you do not need to consume that much. With the RDA at only 2.4 mcg for healthy adults, taking 5000 mcg just creates expensive urine. You can safely dose at lower levels and still reach the RDA.
Ideal Vitamin B12 Dosage for Seniors
In some cases, high doses of 500 to 1000 micrograms per day might be necessary to reverse B12 deficiency.
“Take water-soluble vitamins on an empty stomach with a glass of water,” recommends Dr. Perez-Gallardo. And since it can be energizing, Dr. Perez-Gallardo says that the best time to take vitamin B12 is in the morning, so it won't affect your sleep.
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.
B12 deficiency not caused by your diet is one to two 1,000 microgram tablets, taken once or twice a day – this is usually if you cannot have vitamin B12 injections.
Stores of vitamin B12 in the body can last around 2 to 5 years without being replenished, so it can take a long time for any problems to develop after a dietary change.
Around 50% to 98% of vitamin B12 is excreted from the body 48 hours after injection. Research shows that vitamin B12 has a half-life of 6 days in the blood, making it six days before the administered amount gets excreted from your body.
A B12 ≥ 1000 ng/L was associated with the presence of solid cancer without metastases (OR 1.96 [95%CI: 1.18 to 3.25]) and with metastases (OR 4.21 [95%CI: 2.67 to 6.64]) after adjustment for all elevated B12-related causes.
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.
According to an article in the journal American Family Physician, researchers have found that supplements containing as much as 1,000 times the recommended daily allowance (RDA) are safe. The body does not absorb vitamin B-12 well.
Interactions between your drugs. No interactions were found between Vitamin B12 and Vitamin D3. However, this does not necessarily mean no interactions exist. Always consult your healthcare provider.
Is 5000 mcg of B12 too much? A dosage of 5000 mcg of Vitamin B12 has been deemed a safe dosing amount. In fact, it is often recommended for those who have a health condition that affects their B12 absorption. Consultation with a qualified health professional is always recommended.
Once you begin treating your vitamin B12 deficiency, it can take up to six to 12 months to fully recover.
Research has shown that Vitamin B12 can assist with recovery from nerve pain associated with neuropathy through the: Revival of nerves. Development of myelination.
The main neurological symptoms include: paraesthesia [8–12], ataxia [9–12], and limb weakness [9, 11]. The most prevalent psychiatric symptoms associated with B12 deficiency include, delusions [12, 13], irritability [13, 14], and decreased interest [15, 16].