Vitamin B12 Injection Sites

Jenna Hilton
October 5, 2023

Vitamin B12 injections balance vitamin deficiencies and provide numerous health benefits, including increased energy levels, faster metabolism, and weight loss. The vitamin’s anti-inflammatory properties also effectively minimize oxidative stress, reducing inflammation and alleviating adrenal fatigue symptoms.

The provider giving a B12 injection will choose the right injection site to ensure efficient vitamin absorption and prevent injury or complications. Read on to learn more about common vitamin B12 injection sites and the techniques used to administer the shot.

Vitamin B12 injection sites.

Best Vitamin B12 Injection Sites

The injection provider can administer the B12 shot deep into the muscle (intramuscularly) or into the tissue layer between the skin and the muscle (subcutaneously).

The choice depends on several factors, such as the injection dose, frequency, and medical equipment. The patient’s comfort level, age, sex, physique, and health goals may also determine the injection location.

Subcutaneous vs. intramuscular vitamin b12 injection.

Intramuscular B12 Injection Sites

Intramuscular (IM) injections yield better results and ensure faster absorption because the substance spreads directly to the muscle tissue. The administrator injects the B12 solution with a 1 to 1.5-inch-long needle deep into the muscle to secure efficient absorption.

The most common B12 intramuscular injection sites are the following:

  • The upper buttocks – The provider inserts the needle into the outer and upper region of the muscle. The injector makes a V-shape with their thumb and forefinger to create a triangle for the insertion. Only a well-trained administrator can perform this to avoid potential damage to the sciatic nerve.
Intramuscular vitamin b12 injection into the upper buttocks area.
  • The shoulder – Experienced doctors commonly administer B12 injections into the upper arm area by inserting the injection into the deltoid (shoulder) muscle. They hold the flesh tight with their fingers and inject the shot into the center of the V-shape. Experts do not recommend this site for self-administrated injections.
Intramuscular vitamin b12 injection into the shoulder area.
  • The thigh – This location is preferable for self-administrated shots. The needle goes into the vastus lateralis muscle located in the thigh’s outer middle section. Hold the skin firmly and create a V-shape with your thumb and forefinger to ensure proper administration.
Intramuscular vitamin b12 injection into the thigh area.

Subcutaneous B12 Injection Sites

Subcutaneous B12 injections are less common yet still effective in treating B12 deficiencies. Some patients report it as a less painful alternative because the needle that goes into the fatty tissue just below the skin is thinner and shorter, usually one-half to five-eighths of an inch long.

The most common B12 subcutaneous injection sites are the following:

  • The upper arm – To self-administer a B12 injection into the arm, pinch a thick skin layer of the side or back of the upper arm and insert the needle at a right angle. This procedure may require help from another person.
Subcutaneous vitamin b12 injection into the upper arm area.
  • Front of thigh – This is a popular self-injection site because of its convenience and low discomfort level. Pinch a layer of skin in the front thigh area with your thumb and index finger to inject the shot.
Subcutaneous vitamin b12 injection into front of thigh region.
  • The lower abdomen – This is the most common subcutaneous injection spot for self-administrated shots. The injector inserts the needle into the pinched skin layer two inches below the navel.
Subcutaneous vitamin b12 injection into lower abdomen.

Common Concerns About B12 Injection Sites

The most common concerns regarding B12 injection sites revolve around the procedure’s safety, effectiveness, and potential complications.

Proper administration secures optimal results, prevents damage to the surrounding tissue, and reduces pain and discomfort.

Are B12 Shots Subcutaneous or Intramuscular?

B12 shots can be both subcutaneous and intramuscular. The injection method depends on the patient’s comfort level, physique, and the desired absorption rate.

Some individuals opt for faster absorption with IM shots, while others prefer the slower, controlled absorption that subcutaneous injections provide.

What Happens When a B12 Shot Is Administered Incorrectly?

An untrained injector can provoke mild or moderate to severe side effects with incorrect administration. The most common risk factors are the following:

  • Bruising or swelling may occur if the needle hits a blood vessel or damages soft tissue.
  • A burning sensation at the injection site happens when the administration is too fast.
  • Post-injection skin inflammation and infections may occur due to unsanitary administration or a reaction to the medicine.
  • Allergic reactions, such as a rash, itching, swelling, or redness, happen due to high vitamin dosage or as a response to the needle coating.
  • Nerve damage happens when the provider places the needle incorrectly or at an inappropriate angle, causing numbness, tingling, or pain.

How Painful is a B12 Injection?

B12 injectables are minimally invasive treatments that may cause mild tenderness or pain.

They can be slightly uncomfortable and produce a tingling sensation at the injection site. This depends on the individual pain tolerance, needle size, injection technique, and injection site.

Subcutaneous B12 shots tend to be less painful because the needle is not inserted deeply. Additionally, the provider can apply topical numbing cream to the injection area to minimize the discomfort.

Note: Another quick way to replenish Vitamin B levels is via IV therapy. Learn more about the benefits of Vitamin B IV Therapy as well as what the procedure looks like.


Finding the best location for a B12 injection is crucial for correct administration. Accurate injection prevents potential damage, pain, or infection. It also enables even distribution and quick absorption for better health results.

Vibrant Skin Bar offers Vitamin B12 injections and is located in Phoenix, Arizona. Contact us for more information or buy a shot to use later.

Jenna Hilton
Jenna Hilton has been a practicing PA since 2009, specializing in Family, Internal Medicine and Medical Aesthetics. She attended Arizona State University where she received her Bachelor's Degree and graduated magna cum laude. She received her Master of Science degree in Physician Assistant Studies from A.T. Still University.

Jenna has been injecting neurotoxin and dermal filler since 2013. She received certification as a Master Injector in 2017 through Empire Medical in Los Angeles, California. She is currently working on a Fellowship Program in Anti-Aging and Regenerative Medicine through the American Academy of Anti-Aging Medicine. Her special interests include use of PLLA, Ablative/Non ablative skin resurfacing, PDO threads, hormone therapy and nutritional therapies to improve cellular regeneration and medically supervised weight loss.

Jenna Hilton believes in a multi-factorial approach, considering internal factors that accelerate aging and disease development. She always enjoys teaching. She co-founded Vibrant EDU courses at Vibrant Skin Bar and regularly performs one-on-one training with fellow injectors. She teaches Aesthetic and Advanced Injectable Courses at National Laser Institute. She has been named Preceptor of the Year and is an Adjunct Faculty Member at Midwestern University. She was born in Iowa, and lives with her husband and three children in Phoenix, AZ.

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