Getting a prescription for B12 shots starts with a blood test showing you’re deficient, followed by a visit (in person or virtual) with a provider who can write the prescription. The process is straightforward, but insurance coverage and the type of injection you receive depend on why your levels are low and whether your body can absorb B12 on its own.
What the Doctor Needs to See
Your provider will order a serum B12 blood test, and possibly additional markers like methylmalonic acid or homocysteine, which rise when B12 is too low. These secondary markers help clarify borderline cases where your serum B12 looks normal but your body still isn’t using it properly.
Injectable B12 is specifically indicated when your body can’t absorb the vitamin through your digestive system. The most common reasons include:
- Pernicious anemia: an autoimmune condition where your stomach stops producing intrinsic factor, a protein required to absorb B12. This is irreversible.
- Gastric or bariatric surgery: procedures that remove or bypass part of the stomach eliminate the cells that produce intrinsic factor and stomach acid, both essential for B12 absorption.
- Celiac disease or Crohn’s disease: damage to the small intestine can prevent adequate B12 uptake from food.
- Long-term medication use: metformin (for diabetes) and proton pump inhibitors (for acid reflux) both reduce B12 absorption over time.
- Dietary deficiency: strict vegans or vegetarians with very low levels may qualify, especially if oral supplements haven’t raised their numbers.
If your deficiency is purely dietary and you have no absorption issues, many doctors will try high-dose oral supplements first. Injections become the treatment when pills aren’t working or when there’s a clear reason your gut can’t do the job.
Steps to Get the Prescription
Schedule an appointment with your primary care provider. Mention your symptoms (fatigue, numbness or tingling in hands and feet, brain fog, balance problems) and ask for a B12 blood test. If you’ve already had bloodwork done elsewhere showing low levels, bring those results.
Once your labs confirm deficiency, your doctor determines the cause. This might involve additional testing for intrinsic factor antibodies (to check for pernicious anemia) or a review of your medical history for surgery, gut conditions, or medications that interfere with absorption. The underlying cause matters because it dictates whether you need injections temporarily or for life.
If injections are appropriate, your provider writes the prescription. You can fill it at a regular pharmacy. The prescription typically specifies the form of B12, the dose in micrograms, how often to inject, and whether it’s intramuscular (into muscle) or subcutaneous (under the skin).
Telehealth as an Option
Telehealth providers can legally prescribe B12 injections in most states, but the same clinical standards apply as an in-person visit. A provider must conduct an appropriate medical evaluation and review your clinical history before writing any prescription. An online questionnaire alone doesn’t meet the standard of care in most states. You’ll need to have lab results available, either from a recent doctor visit or from a lab order the telehealth provider sends you.
Several online health platforms now offer this service. You typically upload recent bloodwork or get directed to a local lab, then have a video consultation where the provider reviews your results and writes the prescription if appropriate.
What a Typical Treatment Schedule Looks Like
B12 injection treatment happens in two phases: loading and maintenance. During the loading phase, you receive frequent shots to replenish your depleted stores quickly. For deficiency without nerve symptoms, this typically means injections every other day for one to two weeks. If you have neurological symptoms like numbness or difficulty with balance, the loading phase uses higher doses on the same schedule.
After loading, you shift to maintenance injections, usually 1,000 micrograms every two to three months. People with pernicious anemia or permanent absorption problems stay on this schedule indefinitely. Those who had a temporary cause, like a medication side effect, may eventually transition back to oral supplements once the underlying issue is resolved.
Cyanocobalamin vs. Hydroxocobalamin
The two main injectable forms of B12 are cyanocobalamin and hydroxocobalamin. In the United States, cyanocobalamin is the most commonly prescribed form and is widely available as an injectable solution and nasal spray. Hydroxocobalamin is used more frequently in the UK and Europe for deficiency treatment, while in the US it’s primarily stocked in emergency settings for cyanide poisoning (under the brand name Cyanokit), though it can be prescribed for deficiency as well.
Hydroxocobalamin stays in the body longer, which can mean less frequent injections for some patients. Your provider will choose based on availability, your specific condition, and how your body responds.
Self-Injecting at Home
Most people who need ongoing B12 shots learn to inject themselves at home rather than visiting a clinic every time. Your provider or a nurse will walk you through the technique during your first appointment. The injection goes into a large muscle, usually the outer thigh, using a standard intramuscular needle.
The supplies are simple: a syringe, an injecting needle, the B12 ampoule, alcohol wipes, gauze, and a sharps container for used needles. Many pharmacies sell sharps containers, and some municipalities offer free disposal programs. The actual injection takes under a minute once you’re comfortable with the process. Most people describe it as a brief pinch with mild soreness at the site afterward.
Insurance Coverage and Cost
Insurance, including Medicare, covers B12 injections when they’re medically necessary. To qualify for reimbursement, your medical record needs to document your diagnosis with a matching diagnostic code, along with lab results showing your B12 levels. Your provider should keep progress notes and lab values on file, as insurers can request this documentation during a review.
Without insurance, a vial of injectable cyanocobalamin (which contains multiple doses) typically costs between $20 and $50 at most pharmacies. The syringes and needles add a few dollars. Compared to in-office injections, where you’re also paying for the visit, self-injection at home with a prescription is significantly cheaper over time.
If your provider prescribes B12 shots but your insurer pushes back, the most common reason is incomplete documentation. Make sure your lab results and diagnosis are clearly noted in your chart before the claim is submitted.
Who Should Not Get B12 Injections
B12 injections are safe for the vast majority of people, but a few conditions require caution. If you have a known allergy to cobalt (the metal at the center of the B12 molecule) or have previously reacted to a B12 injection, you should not receive another one. People with low potassium levels or certain heart rhythm problems need to be monitored carefully, because correcting a severe B12 deficiency can temporarily shift potassium levels further as your body starts producing red blood cells rapidly. Your provider will check for these issues before starting treatment.