B12 in food gets harder to absorb with age. That is why experts say to rely mainly on pills or fortified food from age 50 on (Institute of Medicine 1998). At 65 and older, the simple plan is one B12 pill every day.
Daily amounts are in the B12 chart for seniors.
Ready to buy:
NatureWise Vitamin B12 1000 mcg
$0.12 a day. A softgel on NSF’s testing list, and the cheapest tested pill.
Which B12 fits you?
Here is the best choice for each common situation.
Over 65, or on metformin or an acid reducer? A daily pill covers you.
Metformin can lower B12 over the years (de Jager 2010), and so can long use of acid reducers such as omeprazole (Lam 2013). Keep taking your medicine, and ask your doctor for a B12 test. Our pick above is on NSF’s testing list.
Blood test came back low? Ask your doctor about 1,000 mcg a day.
In a trial of 120 older people with mildly low B12, about 650 to 1,000 mcg a day worked best. Doses of 100 mcg or less did much less (Eussen 2005). With pernicious anemia or nerve symptoms, your doctor will likely use shots instead. If your doctor prefers methylcobalamin, this capsule gives 1,000 mcg of it and is on two NSF testing lists.
Thorne Vitamin B12 (methylcobalamin)
$0.40 a day
Taking a multivitamin for seniors? Check the B12 on the label.
Many multivitamins hold only a small amount of B12 (see the chart below). That keeps a normal level for most people, but it will not fix a low one. This one has 600 mcg in its two-capsule serving and is NSF Certified for Sport.
Thorne Basic Nutrients 2/Day multivitamin
$1.33 a day
How much B12 seniors need each day
| What it is | B12 |
|---|---|
| What you need each day (RDA) | 2.4 mcg |
| A typical multivitamin | 5 to 25 mcg |
| A typical B12-only pill | 500 to 1,000 mcg |
The 1,000 mcg pill is the most common size: about 1 in 3 of the 203 B12 labels we read hold exactly that much.
Why B12 gets harder to absorb as you age
B12 in food is bound to protein, and stomach acid has to free it. Many older adults make less stomach acid. A common cause, atrophic gastritis, affects about 2% of all people but 8% to 9% of adults 65 and older (NIH).
The B12 in pills and fortified foods is already free, so low stomach acid does not block it (Baik 1999).
How common is low B12 in older adults?
In adults 60 and older, 3.7% have a blood B12 level low enough to count as deficient, and 12.3% are low or borderline (NIH). About 1 in 5 has at least one abnormal result on a B12 blood test (NIH). Numbness, balance trouble and memory changes are easy to blame on age. If you notice them, ask for a test. Signs of low B12.
What is the most B12 a senior can take?
There is no official upper limit for B12 (NIH). If you have kidney disease, ask your doctor which form and dose to take.
One large study tracked B12 pill use over 10 years (Brasky 2017). Men who averaged more than 55 mcg a day from single-vitamin pills had about twice the lung cancer risk of men who took none. The risk was highest in smokers. A 1,000 mcg pill is far above that amount. The study shows a link, not proof, but men who smoke should ask a doctor before taking B12 pills for years. More in our B12 safety guide.
Frequently asked questions
How much B12 should a 70-year-old take?
Most people in their 70s do well on one B12 pill a day, the same plan as anyone 65 or older. If a blood test shows you are low, follow the dose your doctor sets.
Does B12 help memory in older adults?
Not if your B12 is normal. Trials of B12, alone or with folic acid, for 1 to 2 years did not improve memory or thinking in older adults (NIH). Low B12 can cause memory problems, so memory changes are a reason to get tested.
Which form of B12 is best for seniors?
Either main form works. Cyanocobalamin is cheaper, more common, and the form used in the dose trial in older adults. Methylcobalamin costs more and has not been shown to be absorbed better (NIH). Take the one you will remember every day. More in methylcobalamin vs cyanocobalamin.
Is B12 under the tongue better for seniors?
No. In a small trial, tablets held under the tongue raised B12 no more than tablets that were swallowed (Sharabi 2003). Choose whichever form you find easiest to take.
Related guides
- B12 dosage guide: the amount for every age, and why pill doses are so high
- B12 deficiency signs: the symptoms to watch for
- The MMA test: the test that confirms a borderline result
- B12 for vegans: pills made without gelatin
Sources
- NIH Office of Dietary Supplements. "Vitamin B12: Fact Sheet for Health Professionals" (RDA, older adults, atrophic gastritis, low B12 in a national US health survey (NHANES) 2007 to 2018, supplement amounts, memory trials, shots, no upper limit). ods.od.nih.gov (updated July 2, 2025; read October 15, 2026).
- Institute of Medicine. Dietary Reference Intakes, chapter 9: Vitamin B12. National Academies Press, 1998 (advice for adults over 50).
- Baik HW, Russell RM. "Vitamin B12 Deficiency in the Elderly." Annu Rev Nutr. 1999. PMID: 10448529
- de Jager J, et al. "Long term treatment with metformin in patients with type 2 diabetes and risk of vitamin B12 deficiency." BMJ. 2010. PMID: 20488910
- Lam JR, et al. "Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency." JAMA. 2013. PMID: 24327038
- Eussen SJ, et al. "Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: a dose-finding trial." Arch Intern Med. 2005. PMID: 15911731
- Brasky TM, et al. "Long-term, supplemental, one-carbon metabolism-related vitamin B use in relation to lung cancer risk in the Vitamins and Lifestyle (VITAL) cohort." J Clin Oncol. 2017. PMID: 28829668
- Sharabi A, et al. "Replacement therapy for vitamin B12 deficiency: comparison between the sublingual and oral route." Br J Clin Pharmacol. 2003. PMID: 14616423
- NIH Dietary Supplement Label Database: the Thorne Basic Nutrients 2/Day label.
- Prices are each brand’s list price, checked October 15, 2026 (Thorne Basic Nutrients September 29, 2026). Amazon’s price may differ.