Take a B12 pill every day if you are over 50, vegan or vegetarian, or have taken metformin or an acid reducer for years. One pill a day covers it. If you eat meat or fish and none of these fit, food usually gives you enough.
The amount for every age is in the B12 dose chart.
Ready to buy:
NatureWise Vitamin B12 1000 mcg
$0.12 a day. On NSF’s testing list, and the lowest cost of the tested pills.
Which B12 is right for you?
The right kind of B12 depends on why you take it. Over 50, or on metformin? Up to 3 in 10 people over 50 don’t absorb B12 from food well, so experts advise getting most of it from a pill or fortified food. Metformin and years of acid reducers can lower B12 too. Our pick above works for that.
Already take a multivitamin? Check how much B12 it has.
Many multivitamins hold only a few mcg of B12. That is fine if you also eat animal foods. If you want one pill that covers B12 too, this one has 600 mcg in its 2 capsules and is NSF Certified for Sport.
Thorne Basic Nutrients 2/Day multivitamin
$1.33 a day
Vegan? You need a B12 pill, and many are not vegan.
Plants have no B12 unless it is added. Many softgels, including our top pick, are made with gelatin. This lemon chewable is labeled vegan. More in B12 for vegans.
Jarrow Methyl B-12 1000 mcg, lemon chewable
$0.13 a day
Vegetarian? Eggs and dairy may not be enough.
Only animal foods have B12, so vegetarians who eat eggs or dairy but no meat are more likely to run low (NIH). If your level is normal, a small 100 mcg tablet a day is a cheap way to keep it there, and it is labeled vegan. It is too small to fix low B12 (Eussen 2005).
Carlyle Vitamin B12 100 mcg
$0.04 a day
Blood test says your B12 is low? A daily pill often fixes it.
In a trial of 283 adults 65 and older with low B12, 1,000 mcg a day brought more than 90% back to normal within 8 weeks (Sanz-Cuesta 2020). With pernicious anemia, nerve symptoms or past weight-loss surgery, your doctor may use shots instead. This capsule holds 1,000 mcg of methylcobalamin and is tested by NSF.
Thorne Vitamin B12 (methylcobalamin)
$0.40 a day
How much B12 per day, by age
| Who | B12 a day |
|---|---|
| Babies, birth to 6 months* | 0.4 mcg |
| Babies, 7 to 12 months* | 0.5 mcg |
| Children 1 to 3 | 0.9 mcg |
| Children 4 to 8 | 1.2 mcg |
| Children 9 to 13 | 1.8 mcg |
| Teens 14 to 18 | 2.4 mcg |
| Adults 19 and older | 2.4 mcg |
| Pregnancy | 2.6 mcg |
| Breastfeeding | 2.8 mcg |
* Babies: a target set from what healthy breastfed babies get. Do not give a child an adult B12 pill unless a doctor says to.
Why B12 pills hold 1,000 mcg
Your body can take in only about 1 to 2 mcg of B12 at a time the normal way. A little more soaks straight through the gut wall. In all, you absorb about 1.3% of a 1,000 mcg pill, or about 13 mcg, which is several times what you need (NIH).
That is why the typical label holds 1,000 mcg: about 1 in 3 of the 203 B12 labels we read hold exactly that much, and about 1 in 8 hold 5,000 mcg or more.
Under the tongue or swallowed?
Either works. Under-the-tongue B12 worked no better than a swallowed pill (Sharabi 2003). A 2025 review of 16 studies found no clear difference between the two (Mazur 2025). Take the kind you will remember every day.
Is high-dose B12 safe?
No upper limit has been set for B12 (NIH). Side effects, bigger doses and who should check first are in our B12 safety guide.
If your doctor wants a higher dose, NOW Methyl B-12 5000 mcg lozenges hold 5,000 mcg each and are labeled vegan.
Ask a doctor before you start if you have kidney disease, early Leber’s disease (an inherited eye disease) or a cobalt allergy (FDA label). Get numbness, balance trouble or memory changes checked, whatever you take.
Frequently asked questions
Can I take B12 every other day or once a week?
To keep a normal level, some people do. In one trial of older adults, 74% of people who moved to one pill a week still had a normal level a year later (Sanz-Cuesta 2020). For vegans, the Vegan Society suggests at least 2,000 mcg once a week. If you were low, ask your doctor before you cut back.
Do B12 pills work as well as shots?
For raising blood B12, small trials found high-dose pills worked about as well as shots. A Cochrane review rated that evidence low quality, and none of the trials measured how people felt (Wang 2018).
Which is better, methylcobalamin or cyanocobalamin?
For most people, buy cyanocobalamin: it works as well, and the tested pills cost less. Methylcobalamin is fine if you prefer it. More in methylcobalamin vs cyanocobalamin.
Related guides
- How much B12 should seniors take: the over-50 dose and the trial behind it
- B12 deficiency signs: symptoms and the two blood tests
- B12 1,000 mcg: which one to buy
- Best B12 supplements: our full ranking
Sources
- NIH Office of Dietary Supplements. "Vitamin B12: Fact Sheet for Health Professionals" (RDA Table 1, absorption by dose, forms, 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).
- 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
- The Vegan Society. What every vegan should know about vitamin B12 (weekly 2,000 mcg route).
- Sanz-Cuesta T, et al. "Oral versus intramuscular administration of vitamin B12 for vitamin B12 deficiency in primary care (OB12)." BMJ Open. 2020. PMID: 32819927
- NICE. Vitamin B12 deficiency in over 16s: diagnosis and management (NG239), 2024 (shots after stomach surgery). Read October 16, 2026.
- Eussen SJ, et al. "Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: a dose-finding trial." Arch Intern Med. 2005. PMID: 15911731
- Sharabi A, et al. "Replacement therapy for vitamin B12 deficiency: comparison between the sublingual and oral route." Br J Clin Pharmacol. 2003. PMID: 14616423
- Mazur M, et al. "Efficacy of sublingual and oral vitamin B12 versus intramuscular administration: insights from a systematic review and meta-analysis." Front Pharmacol. 2025. PMID: 41487531
- Wang H, et al. "Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency." Cochrane Database Syst Rev. 2018. PMID: 29543316
- FDA. Cyanocobalamin injection label (Leber’s disease, cobalt). DailyMed
- NIH Dietary Supplement Label Database: 203 B12 labels (August 2026), and 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.