Subcutaneous Vitamin B12 Injections


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Basically, this is an injection under the skin into the fatty tissue. It may sound unpleasant, but when done right, administering such an injection can be virtually painless, and will allow the absorption of vitamin B12 over a 24-hour period. A dosage of 2ml is recommended as safe, anything more could cause irritation at the injection site. As with anything healthcare-related, it should be learnt from a professional.

Instructions for self-administering a vitamin B12 subcutaneous injection:


We recommend seeking professional help before self-administering an injection, however, if you do wish to self-administer, here are some guidelines to help.


Safety first:

  1. Always use a sterile needle – don’t touch it.
  2. Wipe the surface of the skin, and vial or ampule, with separate alcohol wipes.
  3. Prior to insertion, use a fresh alcohol wipe to clean the vial and let it dry
  4. Only touch the skin you intend to pinch
  5. Always use clean needles and dispose of old ones properly
  6. Keep vials and needles in a safe, secure place away from children


  • Vial or ampoule of vitamin B12 or B-Complex
  • 27-29 gauge needle, 1/2” or 5/8” inch length (insulin needles commonly used)
  • Alcohol wipes
  • Gauze or cotton ball
  • Bandage
  • 1-2ml syringe depending on the injection quantity
  • Sharps biohazard container or homemade sharps container for needle and syringe disposal

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How to Perform a Subcutaneous Injection of Vitamin B12

Here are 12 easy-to-follow steps to self-administer a subcutaneous injection:


cartoon hand with needle and syringe

The steps below are for informational purposes only and not meant as a complete how-to for subcutaneous injection. Before self-injecting, we always recommend seeking professional instruction from a certified healthcare practitioner.

  1. Wash your hands and fingernails with soap and warm water for no less than 20 seconds.
  2. Inspect the injection site to ensure it is clear of bruising, swelling, irritation or hardness.
  3. Use an alcohol wipe to clean the surface of the ampoule or the top of the vial and let it dry.
  4. Open the syringe and needle packets then snuggly fasten the needle onto the end of the syringe.
  5. Clean the skin using isopropyl alcohol on a cotton ball or an isopropyl alcohol wipe. Begin at the injection site then use a circular motion continuing outward into a larger circle. Allow the site to dry.
  6. Draw air into the syringe (the same number of milliliters as the vitamin you plan to inject). While the vial is lying on the table, insert the clean needle into the top of it and inject the air into the vial. This helps to force the liquid vitamin into the syringe.
  7. turn the solution container upside down and slowly pull on the plunger to withdraw the desired dosage of vitamin B12 into the syringe. Tap the syringe to release air bubbles and then depress the plunger to remove all the remaining air and check to see that the dosage is correct. Never inject yourself when air is present inside the syringe chamber.
  8. Using your thumb and index finger about 1 ½" apart pinch the skin, which will pull the fat away from your muscle.
  9. Using a 90-degree angle, quickly insert needle into the pinched skin. Hold the needle in place, push down on the plunger, and insert all of the solution. Often injecting it slowly can reduce any irritation.
  10. Let go of the pinched skin and withdraw the needle at the same 90-degree angle of insertion.
  11. To stop any bleeding, apply pressure with gauze or a cotton ball.  There can be some minor bruising later, but this is not a cause for concern.
  12. Place the used syringe and needle into a biohazard sharps container, and then rub the injection site in a circular motion for 2-3 minutes, which will activate the vitamin and help ease any irritation at the injection site.

Ensure you vary the injection site to avoid complications, i.e. if you inject in your right abdomen on Tuesday then on Thursday use the left side, and if you inject in your right thigh on Thursday, use your left on Sunday. While subcutaneous injections are not difficult to perform, some people choose to have them administered by trained professionals.

Finally, to guarantee your good health, it is important to be vigilant for infection, and the signs are severe pain, swelling, redness, warmth or drainage at the injection site. These signs should be immediately reported to your doctor.

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Looking for intramuscular injections?
How to Perform an Intramuscular Injection of Vitamin B12



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