B12 Injection sites + How to use B12 Shots Safely

B12 Injection sites + How to use B12 Shots Safely

B12 shots can help improve energy levels, sleeping patterns, help with weight loss and even improve hair growth. 

In order to get these benefits you need to be using the right type of B12 and using it correctly, that means in the right injection sites and the correct depth.

Use this guide to help determine if you are using B12 correctly and how to inject B12 correctly.

You can also find information on how to purchase high-quality B12 supplements below: 


Intramuscular vs Subcutaneous

If you've already decided on using B12 shots over oral or sublingual forms of B12 you are already ahead of the curve.

B12 shots are far superior to oral forms of B12 due to the fact that they have superior absorption and quickly get into your target tissues (where B12 has its action). 

While you can most certainly give yourself a B12 shot at home, there are a few things you need to know to make sure you are doing it safely and effectively.

We will go into detail on what is important and why below, but first I want to talk about the various routes of administration.

What I mean is the difference between intramuscular B12 injections and Subcutaneous B12 injections.

Intramuscular means exactly that: the injections is IN the muscle.

This should be compared to a subcutaneous injection in which the needle tip goes into the subcutaneous space rather than the needle. ​

subcutaneous b12 injection in the skin

The muscle is obviously deeper than your subcutaneous tissue (you can see the image above for reference). 

But the question is:

Does it matter whether your B12 shot is subcutaneous or intramuscular?

The answer is that it really depends, but in my experience, MOST patients are fine to use subcutaneous injection sized needles. 

Most patients (provided they are lean) will be able to put a subcutaneous needle VERY close to the muscle (if not inside) depending on the site they use for the injection. 

The subcutaneous layer is thicker in people who have more body fat and therefore patients with a higher BMI may need a longer needle to adequately get into the skeletal muscle. 

With that in mind here are the injection sites you can use on your body for B12 shots: 

  • Mid-thigh (right into your quadriceps): This is the preferred site if you are self-injecting. Why? Because you have easy access to this large muscle and it's easy to avoid major blood vessels. This location can have more fat than other areas on the body and may not be the best area if you have excess body fat. You can see the video below for a demonstration of using this area. 
  • Upper arm or shoulder area (right into your deltoid): The deltoid is the preferred area if someone you know is giving you the injection at home. There is generally less adipose tissue in this area. I don't necessarily like this area because there is a small chance (very small) of nerve damage (1).
  • Gluteal region (into major glut muscles): This is another area that you can give an injection although one that I don't recommend. There are large vessels and nerves in this area and this area should really only be used if there are no other options. 
YouTube video

You can boil it down to this:

If you are giving it to yourself consider using your thigh.

If you need someone to give it to you, consider using the deltoid/shoulder. ​

One final point before we move onto questions and answers.

In my experience, the intramuscular route is superior to subcutaneous injections.


Because your skeletal muscles are filled with mitochondria (the portion of your cell responsible for energy production in your body) and we know that B12 directly acts in these mitochondria. 

In my experience, injections in the skeletal muscles (intramuscular injections) result in a more dramatic improvement in symptoms including energy and weight loss. 

While this may not be true for EACH and EVERY person, it's still worth considering. ​

How to give yourself a B12 shot at home: ​

Methylcobalamin vs Cyanocobalamin

If you are using B12 shots it's also very important that you use the correct form of vitamin B12. 

Vitamin B12 (when it comes to injections) come in two flavors:

  • Cyanocobalamin <--- Cheaper form of B12 that is NOT premethylated and still requires methylation once in your body
  • Methylcobalamin <--- Pre methylated and active form of B12 ready to be used by the body

If you are getting B12 it's generally best to get yours in the methylcobalamin form. 

Methylcobalamin has been shown to be superior to cyanocobalamin (2) at improving circadian rhythms in some patients who trialed both versions.

Taking cyanocobalamin if you have a methylation issue or MTHFR defect (3) in your genes can also cause issues as your body attempts to methylate the B12 before it can utilize it completely. 

This process may explain why some patients respond to methylcobalamin but NOT cyanocobalamin.

If you decide to use B12 shots make sure you know WHICH type of B12 you are getting. ​

Where to Buy B12 Shots​

If you decide to get B12 shots you need to make sure that you are getting high-quality pharmaceutical grade methylcobalamin in a high enough dose. 

That means at each shot should be at least 5,000mcg of methylcobalamin NOT cyanocobalamin.

If you are suffering from fatigue, low energy or weight gain B12 shots would be worth considering. 

B12 shots FAQ: 

Why B12 shots over oral forms?

Oral and sublingual B12 forms must get absorbed before they are active in your body. 

Any sort of GI problem (including hormone imbalances like thyroid problems) may limit absorption.

In fact, the absorption of B12 requires that you have adequate stomach acid (among many other factors), which means that if you are taking acid blockers for reflux you are likely reducing your absorption of B12.

It's been my experience that many patients on oral and sublingual forms of B12 notice a dramatic improvement upon switching to B12 shots.


Because the absorption of B12 shots is superior because it doesn't require GI absorption.

It also allows for 100% absorption right into your skeletal muscle where B12 can increase mitochondrial energy production. ​

​Who should consider B12 shots? 

It's been reported that as many as 40% of patients in the US may have suboptimal energy levels.

Testing serum levels of B12 can be done, but serum B12 levels tend to be highly inaccurate. 


Because when it comes to nutrients and vitamins we don't necessarily care about what is in your serum, we care about what is actually getting into your cells. 

Unfortunately testing your serum levels of B12 does NOT tell you much is actually in your cells. 

In addition, B12 must be activated in your body (through a methylation process) in order to be used correctly. 

That is why tests like methylmalonic acid (4) tend to be much more accurate than serum B12 levels. 

​It's possible (and highly likely) that you may have NORMAL B12 levels but still have a functional deficiency of vitamin B12 in your body. 

In the most basic sense, it means that you have enough B12 floating around in your body, but you aren't activating the B12 to be used.

By taking B12 shots you can bypass this process and directly activate the B12. ​

What are the benefits of B12 shots? 

Because B12 is present in almost every cell in your body, the benefits from B12 tend to be far-reaching.

I've written about the benefits of B12 shots here, but I will quickly go over the most common benefits that I see in my patients: ​

  • Increases energy and reduces fatigue
  • Increases metabolism and basal metabolic rate
  • Helps with weight loss
  • Improves sleep and circadian rhythm
  • Increases mood and concentration
  • Boost in immune function
  • Increases hair growth

The benefits depend on the person and what symptoms they have prior to taking the B12 shot. 

Will B12 shots help with weight loss? ​

Yes, B12 shots can help with weight loss by improving your metabolic rate (metabolism) and by increasing energy levels. 

The combination of increased energy and increased metabolism to the majority of the heavy lifting when it comes to weight loss. 

It's important to note that taking B12 by itself and hoping for weight loss is NOT the best way to use B12.

Instead, you should use a combination of lifestyle changes, dietary changes, exercise changes in conjunction with your B12. 

You can also combine B12 with other lipotropic components to further boost fat loss.

Lipotropics include nutrients like methionine, inositol, and choline. 

Back to you:

​B12 can be safely used to increase energy and help with weight loss. 

It's important that you understand the right TYPE of B12 to use and where/how to inject it.

If you follow these instructions you will have the best results.

Now it's your turn:

​Have you tried B12 shots before?

Did they help you increase your energy?

Leave your comments below! ​

References (Click to Expand)

About Dr. Westin Childs

Hey! I'm Westin Childs D.O. (former Osteopathic Physician). I don't practice medicine anymore and instead specialize in helping people like YOU who have thyroid problems, hormone imbalances, and weight loss resistance. I love to write and share what I've learned over the years. I also happen to formulate the best supplements on the market (well, at least in my opinion!) and I'm proud to say that over 70,000+ people have used them over the last 6 years. You can read more about my own personal health journey and why I am so passionate about what I do here.

P.S. Need more help? Check out my free thyroid downloads and resources.

36 thoughts on “B12 Injection sites + How to use B12 Shots Safely”

  1. Dear Dr. Childs:

    Your Hashimoto’s Free Diet Guide link is broken to download to ebooks. I opened it in two different browsers and neither yielded your free ebook.
    In addition, I called my son, whom is a IT tech for Baylor Medical in Dallas, and he was also unable to download this.

    Would you have your techs to look at this please?

    Thank you so much for every bit of information you have given free above. I am learning things I that I did NOT know in depth…only surface. God bless you, Doctor, for you wonderful, wonderful blog.

    Sincerely and with thank,

    Gloria (Texas gal)

    • My MMA urine was over the normal range so I took 6 injections but they were only 1000 mcg. How long before symptoms start to improve? Mine is mostly chronic fatigue with insomnia and depression.

      Also, do I need to wait a certain amount of days after the last injection before testing again to see if MMA is going down? Thanks for your expertise.

      • Awesome information on how to inject B12 into the body. Some weight loss clinics have been injecting it incorrectly. Thank you for this wealth of information.

  2. In the above article it says ” you can purchse B12 from the link below” But I am not seeing the link.
    Thanks so much

  3. I have Pernicious Anemia and lack the intrinsic factor in my gut. I take a metabolized form of Folate (methyl folate) and Cyanocobalamin, should I be taking the methylcobalamin instead? I have them every other week. Today, we could not get the needle to penetrate my deltoid area on either arm. Which has never happened before in the past?

  4. Hello,

    I have hydrocobalamin shots, which you don’t address. As I understand it, this form is then broken down to adenosylcobalamin and methylcobalamin and it’s a good for to you. What is your opinion please?

    Also, I am hypothyroid and overweight… I will be self-injecting. The needles that came with my product are about 1.5 inches long. I would much prefer the subcutaneous needles shown in the video. Do you think it would be okay for me to use them for injection in the thigh or should I stick with the longer ones I have?

    Thanks much for your help.

  5. Hi Dr Childs, your blog has been a great help. I am only able to get Methylcobalamin injections in 500mcg/ml concentration. In order to dose 5000mcg, I’d have to inject 10ml, which 2x 5ml on each thigh — ouch! As I am on your 2-day 24hr fast and injecting hCG during those 2 days, would it be ok to split the 5000mcg into two 2500mcg injections to be administered over 2 days? Thank you.

  6. Hi there, I was just recently prescribed the MIC ADV Formula Lipotropic plus B12 Injection, and given the insulin size syringes. They seem kinda small for my thigh, so I’m not sure it will reach my muscle area. Since I’m self injecting for the first time, I’m really not comfortable with the upper arm/shoulder. Where would you suggest I inject this type of B12 with a small syringe? Thank you 🙂

  7. Hi Dr. I weigh 190 lbs (my ideal weight is 150) I know I have hypothyroidism but I can’t afford a Dr. My question is “how often can I inject” Tribedoce 50,000 Complejo B, 10 mg, 100 mg, 50 mg/ 2ml ?

  8. I tried to give myself a B 12 shot tonight and I’m pretty sure the B12 ran down my leg the needle was all the way in my leg? Did I push it into fast?

  9. Regarding methylcobalamin vs cyanocobalamin shots, I recently read that cyanocobalamin is metabolized into the 2 active forms methylcobalamin and Adenosylcobalamin. Wouldn’t that mean that discontinuing cyanocobalamin in favor of methylcobalamin also requires Adenosylcobalamin separately?

  10. Hi dr. Childs!

    I have Hashimoto’s and I take combined T3 & T4 medicine, but I still have some facial weakness and pain in the neck on the left side of my face. I had Bell’s Palsy 4 years ago and my B12 is always pretty low. Do you think that my thyroid could have suck a significant effect on facial nerves? Did you encounter something similar with your patients?

    Thank you for your time,

  11. I can’t find Methylcobalamin injections anywhere. I’m in CO. Can you please respond. Currently doing 1000mcg of Cyanocobalamin and I have the MTHFR gene. 52 year old female athlete – mom of 2 teenagers.

    • Hi Candice,

      It’s definitely hard to find them. You can get any doctor to write a prescription for them or you can try a local weight loss clinic. Just be sure they are using methylcobalamin and not cyanocobalamin.

  12. For those of you with chronic Lyme Disease, this is a tremendous help with the fatigue and tremors. I use the methyl cobalamin . 1ml every two weeks , I am not a Dr. But my Dr but my Dr is

  13. I have been taking B12 (Cyanocobalamin)shots for well over five years weekly, since I have had non-hodgkins lymphoma. I am in remission. My body does not get rid of iron well and with this shot it helps or so my doctor says. I feel much better and without the shot I start to get very tired and out of sync. I am anemic most of the time as well. Tell me though what is pre methylated even mean?

    • Hi Jennifer,

      Pre-methylated refers to the form that the B12 comes in. Some people have a hard time using cyanocobalamin (which requires activation) due to genetic mutations in the MTHFR enzyme.

  14. I could only use the compounded Hydroxocobalamin The others made me ache all over. Unfortunately my Dr. passed away and I have gained forty pounds since having an injection in my neck of Dexamethasone.

    The endocrinologist switched me off of Armour saying there was no evidence that I could not convert T4 to T3 That the evidence was only anecdotal I have felt terrible ever since the injection with horrible sweaty hot flashes an inability to sleep for well over a. year Now it is small flashes with turning red and sweating. TSH is in the low .3 numbers. I have told them I need to have a test for the HPA. No one listens

    • Hi Anita,

      The evidence that you don’t convert is anecdotal but anecdotal evidence still matters, especially since YOU are the one feeling that way 🙂 It may be time to find a new doctor.

  15. I’m not an RN but I am a vocational nurse. Can I administer b12 shots to others who don’t want to do it themselves? Or could I get in trouble for that?

    • Hi Mary,

      I don’t really have any knowledge of B12 inhalers so I can’t comment on that method of administration.


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