Vitamin B12 Injection
genericInjectable vitamin B12 (cyanocobalamin) is FDA-approved for treating B12 deficiency and pernicious anemia. Methylcobalamin injections from compounding pharmacies are compounded and not FDA-approved as finished products.
Cost information
$15 - $75/mo
A vitamin B12 injection is a prescription shot of cyanocobalamin used to treat B12 deficiency when the gut cannot absorb enough, most often because of pernicious anemia or stomach or bowel surgery. People with pernicious anemia usually need a shot every month for life, while people whose low B12 comes from diet alone are often treated with pills. Cyanocobalamin injection is FDA-approved and is given into a muscle or deep under the skin, usually at a clinic, after a few weeks of more frequent loading doses. High-dose oral tablets and a weekly nasal spray (Nascobal) are alternatives for some patients, and a clinician decides which route fits your cause of deficiency.
Dosage Format
Standard treatment for B12 deficiency: 1,000mcg intramuscular injection daily or every other day for 1-2 weeks, then weekly for a month, then monthly maintenance. Wellness-focused protocols from telehealth providers may vary. Dosing should be determined by a licensed provider based on blood levels and clinical need.
Type
Generic
Who to discuss it with
Adults with B12 deficiency, those on plant-based diets, or individuals interested in injectable B12 for energy and neurological support
Key distinction
Vitamin B12 deficiency affects an estimated 6-20% of adults, with higher prevalence in older adults and those following plant-based diets. Injectable B12 bypasses absorption issues that can limit oral supplement effectiveness.
Updated · By Treatment Comparison Editorial Team · Sources and scope
Sources: DailyMed (Hikma): Cyanocobalamin injection label · MedlinePlus: Cyanocobalamin injection patient information · MedlinePlus: B12 deficiency anemia · MedlinePlus: Vitamin B12 intake and food sources · DailyMed (Par Health): Nascobal label · Cochrane Database of Systematic Reviews (PubMed): Cochrane review: oral vs intramuscular B12 (2018)
Injection, nasal spray or pills
| Cyanocobalamin injection | Nascobal nasal spray | High-dose oral B12 | |
|---|---|---|---|
| Prescription | Yes | Yes | No, sold over the counter |
| Labeled or typical schedule | Loading doses, then monthly | One 500 mcg spray in one nostril once a week | Daily (1,000 to 2,000 mcg in the Cochrane trials) |
| Who it is labeled or used for | B12 malabsorption, including pernicious anemia | Pernicious anemia in remission after injections, with no nerve involvement; other deficiency | Diet-related low B12; some people with absorption problems |
| Practical notes | Usually given at a clinic; avoid the IV route | Use at least one hour away from hot food or drinks; recheck B12 after a month | Low-quality trial evidence of similar blood levels to injections |
Sources: DailyMed (Hikma): Cyanocobalamin injection label · MedlinePlus: B12 deficiency anemia · DailyMed (Par Health): Nascobal label · Cochrane Database of Systematic Reviews (PubMed): Cochrane review: oral vs intramuscular B12 (2018)
Signs that it is worth testing B12
MedlinePlus lists fatigue, pale skin, shortness of breath on exertion, a sore red tongue, and nerve symptoms such as numbness or tingling in the hands and feet, poor balance and trouble concentrating. Nerve damage from long-standing deficiency can be permanent if treatment is delayed, so these symptoms are a reason to see a clinician rather than self-treat.
Risk is higher in people over 50, vegetarians and vegans, people who have had stomach or intestinal surgery including weight-loss surgery, people with celiac disease, Crohn disease or pernicious anemia, and long-term users of metformin or heartburn medicines.
Sources: MedlinePlus: B12 deficiency anemia · MedlinePlus: Vitamin B12 intake and food sources
Where to Get Vitamin B12 Injection
We could not load these providers' own pages on October 26, 2026, so no prices are listed here. Confirm whether a B12 injection is offered, what it costs and whether labs are required on each provider's site.
Hims
Confirm on Hims' site whether any B12 product is offered and in what form. A supplement is not the same as a prescription injection.
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Ro
Confirm on Ro's site whether B12 is part of any current program, and the full ongoing price.
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Push Health
Connects patients with clinicians who can review a request for a prescription. Ask whether lab results are needed and what the pharmacy charges.
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How Vitamin B12 Injection Works
Normally B12 from food binds to intrinsic factor, a protein made in the stomach, before it can be absorbed in the small intestine. In pernicious anemia the immune system destroys the cells that make intrinsic factor, and stomach or bowel surgery, Crohn disease, celiac disease, long-term metformin and long-term heartburn medicines can also reduce absorption. An injection skips the gut entirely, so the dose reaches the blood whatever the cause. The label warns against giving it into a vein, because almost all of the vitamin is then lost in the urine. Injections only keep levels up while they continue: MedlinePlus notes that stopping can bring back anemia and cause nerve damage.
Side Effects
Common
- • Mild, short-lived diarrhea
- • Itching or a passing skin rash
- • A feeling that the whole body is swollen
Serious risks and warning signs
- • Anaphylaxis: the label reports anaphylactic shock and death and recommends a test dose if sensitivity is suspected. Get emergency care for trouble breathing or swallowing.
- • Low potassium (hypokalemia) when severe megaloblastic anemia is treated intensively, which the label says can lead to sudden death
- • Fluid in the lungs or heart failure early in treatment, and blood clots in the legs (leg pain, swelling, warmth or redness)
- • Fast, severe optic nerve damage in people with early Leber's hereditary optic neuropathy
Eligibility to Discuss With a Clinician
A clinician usually confirms deficiency first with blood tests such as serum B12, methylmalonic acid, homocysteine and a complete blood count, and may test for intrinsic factor antibodies to look for pernicious anemia. Injections are used for absorption problems; low B12 from a vegetarian or vegan diet is usually treated with oral B12. Tell the prescriber about any allergy to cobalt or B12 products, Leber's disease, kidney disease, heavy alcohol use, pregnancy or breastfeeding.
Related Medications
Provider Reviews
Explore providers in the supplements category. This does not mean every provider offers Vitamin B12 Injection; check the exact product with the provider.
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Frequently Asked Questions
Sources and editorial notes
Dosing, routes, warnings and side effects come from the cyanocobalamin injection and Nascobal labels on DailyMed and from MedlinePlus, checked October 26, 2026. The oral vs injection comparison comes from the 2018 Cochrane review. Provider sites could not be loaded that day, so no provider prices are shown. No clinician review is claimed.
Content updated . Source checking is editorial work; it is not a clinical review.
- DailyMed (Hikma): Cyanocobalamin injection, USP 1,000 mcg/mL prescribing informationMedical or regulatory reference · Accessed 2026-10-26
- MedlinePlus: Cyanocobalamin injectionMedical or regulatory reference · Accessed 2026-10-26
- MedlinePlus: Anemia due to vitamin B12 deficiencyMedical or regulatory reference · Accessed 2026-10-26
- MedlinePlus: Vitamin B12Medical or regulatory reference · Accessed 2026-10-26
- DailyMed (Par Health): Nascobal (cyanocobalamin) nasal spray prescribing informationMedical or regulatory reference · Accessed 2026-10-26
- Cochrane Database of Systematic Reviews (PubMed): Wang H, et al. Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency. Cochrane Database Syst Rev. 2018;3:CD004655Medical or regulatory reference · Accessed 2026-10-26