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How to Perform an Intramuscular Injection of Vitamin B12

Performing an Intramuscular Injection of Vitamin B12

Whether vitamin injections are self-administered or given by someone else, knowing how to give a B12 shot will make the process easy and painless. Consult your healthcare professional for the needle size and length that is right for your injection type and location. Before self-injecting, we always recommend seeking professional instruction from a certified healthcare practitioner. The steps below are for informational purposes only.


Common Intramuscualar Injection Sites

The four most common intramuscular injection sites for B12 injections are the shoulder, hip, upper buttocks and the thigh. Doctors commonly choose to give shots in the deltoid (shoulder) muscle, though the gluteus maximus (buttocks) muscle is sometimes used.

The thigh is the most common location for intramuscular self-injections. If you have a capable helper, then the upper buttocks or arm is a good choice and makes receiving the healthful benefits of B vitamins easier. Personally, I use my upper buttocks region



  • 23-25 gauge needle, 1- 1 ½” length Your healthcare professional will instruct per your body type and injection location. More on B12 Injection needles.
  • Alcohol wipes
  • 2-4ml syringe depending upon injection quantity.
  • Sharps biohazard container for needle disposal.


Tip – it is easier if you have a syringe that holds a greater amount than you are injecting. For example, if you are administering a 1-2ml injection, a 3ml syringe can help by holding the larger syringe while drawing the B12.


Deltoid and Thigh Injection Sites

B12 injection site - arm - deltoidIntramuscular Injection Site for B12 - thigh


Buttock Injection Sites

How to Perform an Intramuscular Injection of Vitamin B12How to Perform an Intramuscular Injection of Vitamin B12

Vitamin B12 Injection Instructions

After choosing the injection site, follow these steps for how to give a B12 shot for a painless dosage every time.

  1. Injection quantities vary per individual purpose.
  2. Open the syringe and needle packages but do not extract them until you are ready to insert the needle onto the syringe and withdraw the vitamins.
  3. Snuggly fasten the needle onto the end of the syringe, and if you have to place them down, be sure that there is a sterile cloth to set them.
  4. 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 thoroughly dry before injecting.
  5. Use a new cotton ball to clean the surface of the container with the B12 solution. Before sticking the needle into the vial, always clean the top of the vial with a NEW alcohol wipe. Let dry.
  6. Fill a couple of milliliters of air into the syringe. Turn solution container upside down and slowly insert clean needle into the surface of container. Inject a couple milliliters of air into the vial. This helps to force the liquid vitamin into the syringe.
  7. Pull on the plunger to withdraw the correct dosage of vitamin B12 into the syringe chamber.
  8. Use the thumb and forefinger of the non-injection hand to hold skin of injection site tight.
  9. Insert needle at a 90-degree right angle. *Pull back on the plunger a little to make sure you did not hit a blood vessel. If blood comes back, remove the needle immediately. Do not inject the medicine at this time. Instead, change the needle, reinsert in a slightly different area, and repeat process.
  10. Hold the needle in place, push down on the plunger, and insert all of the solution. There is no rush and often slowly injecting reduces any irritation.
  11. Remove the needle at the same 90-degree angle of insertion.
  12. Apply pressure with cotton ball or adhesive bandage to stop any bleeding.
  13. Place your used needles in a biohazard container. Find a sharps waste container. Sharps refers to all sharp biohazard materials. It is important to keep accidental sticks from happening to humans and animals. It is a humane duty that we properly dispose of our injection waste.
  14. Rub injection site in circular motion. This activates the vitamin so that your body can begin to use it and helps ease any irritation at the injection site.


How to inject B12 into each of these areas

  • Buttocks - injections are best done in the outer and upper region of the muscle. Careful not to go too low (seek instruction). As with shoulder injections, make a triangle with the thumb and forefinger. Hold the flesh firmly within this triangle and insert the needle in the center.
  • Thigh - give injections in the outer middle third of the thigh. Use the aforementioned fingers to form a triangle to hold the flesh firm. Give the injection in the center of the triangle. The muscle here is the vastus lateralis.
  • Shoulder - make a downward-facing triangle over the deltoid muscle on the upper arm with the thumb and forefinger of the non-injection hand. Insert the needle in the center of this triangle.



  • Prior to injecting. If you accidently touch the needle, or it has contact with a non-sterile surface, use a new needle.
  • Use one alcohol wipe to wipe the surface of the vial or ampule and a different wipe for your skin.
  • After you have sterilized the injection area, do not touch the injection site. Only touch the areas where you pull your skin taunt.
  • Always use clean needles and dispose of old needles properly. Do not throw used needles into the garbage. Find out what your local government mandates for proper needle disposal.
  • Do not forget to use an alcohol wipe to clean the top of ampules before you open them.
  • Always keep your B vitamins and needles in a place that is secure and children cannot retrieve and accidently ingest or stick themselves.



While learning how to inject B12, remember these tips for a safe and painless experience.

  • Hold the skin taut to prepare the muscle for injection. Tightened skin makes it easier to insert the needle at the correct angle.
  • Inserting the needle at a right angle and withdrawing it at the same angle reduces pain. If done properly the injection will barely be felt.


*Are you seeking information on subcutaneous injections of Vitamin B12?


Needle Disposal

Safely storing then disposing your used needles is an obligation we owe to our neighbors. Nobody want to be responsible for another human stuck by a used needle. The health risks are too high to be negligent.


FDA Recommendations

-        Locate and buy a sharps biohazard disposal container for B12 needles. Immediately after use, place all needles and other sharps in a sharps disposal container.

-        Dispose of used sharps containers according to community guidelines.

 Sharps disposal containers for b12 injection needles

Until you locate a sharps container, you can set aside an empty glass or plastic bottle and properly label it to avoid confusion of it being thrown out as normal trash. Peel off or mark out the old labels and re-label as “SHARPS” to warn others of its contents.

A used empty liquid laundry container is another viable option. Make sure that the container you choose has a tight fitting lid, no holes and its plastic is thick enough to prohibit punctures.

Be Safe and Be Healthy!


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Disclaimer: The information contained in this website is only for general interest and informational purposes, and is in no way meant to be used to diagnose or prescribe medication or supplementation of any kind to treat any illnesses or symptoms of illnesses. The treatment of illnesses and symptoms mentioned in this website should only be performed in consultation with your physician. In addition, the use, administration and discontinuation of use, of any vitamin supplements purchased on this website should be performed only under the guidance of your physician. Copyright © 2023 B12 Vitamin Store, Inc. All rights reserved.