B12 Shots Benefits & How to Use Them For Weight Loss

B12 Shots Benefits: Weight Loss, Energy & More

Have you heard great things about B12 shots?

Maybe you want some of the benefits from B12 or maybe you have a neighbor or friend who swears that they help with weight loss and energy levels.

If so, this is the guide for you…

We are going to talk about everything you need to know about B12 shots including:

  • Who should take B12 shots
  • How to safely purchase B12 shots so you know you are getting high-quality ingredients that will actually work
  • All of the benefits of B12 shots
  • Why B12 injections and shots are better than sublingual and tablet forms of B12
  • How to determine if B12 shots will work in YOUR body
  • How to safely inject and use B12 shots
  • The right dosage of B12 that you should be using
  • The right form of B12 to use (this is very important!)
  • How B12 can help with weight loss and increase energy levels

Believe it or not, these B12 shots can really help certain people but only if they include high-quality, pharmaceutical-grade ingredients. 

Getting the right type of B12 can be the difference between experiencing many benefits and feeling no difference at all.

Benefits of B12 Shots and Injections

Without a doubt, I’m sure you are aware of Vitamin B12. 

It is THE energy vitamin people take if they are feeling fatigued.

It’s in just about every energy drink, energy supplement, and any type of food or beverage that claims to “boost” energy.

But it is so much more than simply an “energy-boosting vitamin”. 

It’s actually critical to a number of vital cellular functions and believe it or not, despite the fact that it is inside so many beverages and foods, there is still a high chance that you aren’t getting enough.

We will talk about this a little bit later, but it turns out that Vitamin B12 must go through several steps before it is properly absorbed through your GI tract and several hormone imbalances (including thyroid) can alter this absorption.

This can put you in a tricky situation where your body may be getting “enough” in your diet, and yet it isn’t absorbing it completely.

In addition to this, many people have problems metabolizing B12 in low-quality forms like cyanocobalamin due to defects in the MTHFR gene (1) (as many as 40% of people have THIS problem!).

Another big issue is Hypothyroidism. 

As many as 40-50% of Hypothyroid patients have a B12 deficiency (2). 

a study with highlighted text that shows vitamin b12 deficiency is common in primary hypothyroidism.

It also may surprise you that medications can deplete your vitamin B12 levels – I’m looking at you, metformin (3). 

I’m not saying any of this to scare you or to concern you, but to simply bring to your attention that vitamin B12 deficiency is a big deal.

It’s also really important to understand that HOW you take vitamin B12 can make a huge difference.

If you have any sort of GI issue (GERD, reflux, SIBO/SIFO, yeast problems, chronic constipation, etc.) you will have problems taking oral forms of vitamin B12.

Yes, that includes sublingual forms of B12 as well.

This may explain why so many people say they feel amazing when taking vitamin B12 shots and injections even if they were taking oral forms of vitamin B12 previously. 

So how do you know if you need vitamin B12 shots?

Symptoms of Vitamin B12 Deficiency

Like many other nutrient deficiencies, it turns out that blood work really isn’t the best way to determine if you are deficient. 

Many nutrients have their action INSIDE the cell, which means that testing serum and blood levels just give us an indication of what may be available – but that is assuming everything else is working properly: cellular activity, enzyme activity, receptor activity, etc.

Luckily there are other ways to determine deficiencies (we will go over lab work below) like your symptoms.

Because vitamin B12 has a wide array of cellular actions the symptoms of deficiency are quite diverse. 

Symptoms of vitamin B12 deficiency may include any or all of the following:

Perhaps you can relate to one or more of these symptoms noted above? 

Maybe you’ve tried vitamin B12 sublingual or other oral forms? 

Maybe you still have symptoms?

In either event, the fact remains:

Vitamin B12 is a serious deficiency that can lead to multiple negative side effects.

Not only that but it’s estimated that up to 20% of the US population (11) has vitamin B12 deficiency!

So why is it that up to 40% of patients can have a subclinical vitamin B12 deficiency?

Like many other nutrient deficiencies and complex medical problems, it boils down to physician and patient oversimplification of the problem.

Let me explain:

How to Diagnose and Check for Vitamin B12 Deficiency

The problem comes down to diagnosis. 

When was the last time your Doctor ordered serum levels of Vitamin B12 on you?

When was the last time you asked for them?

Vitamin B12 isn’t a test that Doctors order frequently.

In addition to this many Doctors may be using the “standard” lab value reference range instead of the “optimal” reference range.

Even if you do get a Doctor to order your Vitamin B12 level they may still say it’s normal or insist that taking Vitamin B12 is unnecessary and unlikely to help.

There seems to be a trend among physicians that nutrients, vitamins, and supplements have no place in the treatment of patients when in reality they can be an amazing part of a complete treatment plan.

Even considering all of these factors you need to understand that checking vitamin B12 levels in the serum still isn’t the best way to evaluate for B12 deficiency. 

So how do you do it?

How to check for Vitamin B12 deficiency with lab tests: 

  • Serum Vitamin B12 levels: should be in the top 75% percentile of the lab reference range (yes even mid-range can still be too low). Patients with even mid-range to high-range levels of vitamin B12 often still have a high MCV and high homocysteine (discussed below) and can benefit from vitamin B12 levels. 
  • MCV (Mean corpuscular volume): Should be less than 92. This test evaluates the average size of your red blood cells, the higher your MCV is the bigger your red blood cells get (this isn’t a good thing) and only a few things cause this problem (12), vitamin B12 deficiency, and folic acid deficiency being the most common. Please note that iron deficiency can inappropriately lower your MCV and throw this marker off. 
  • Homocysteine levels: Should be < 9-10. High levels of homocysteine can be used as a marker for vitamin B12 and folic acid deficiencies (13). In addition, high levels of homocysteine are an increased risk factor for developing stroke and cardiovascular disease (14). 
  • Urinary organic acids and methylmalonic acid testing: These can be helpful for diagnosing other nutrient deficiencies but in the case of vitamin B12 deficiency the above tests are usually sufficient for diagnosis.

Now when was the last time you had any of those tests run? 

Or when was the last time someone looked at your labs with an “optimal range” in mind?

I’m guessing they probably never have, but here they are with science to back them up as being sensitive markers for vitamin B12 deficiency.

It actually gets even a little more complex when you consider that the above tests aren’t always 100% accurate either.

Your serum B12 levels represent what’s in your serum, NOT in your cells and that’s where B12 has its action.

lab tests showing a low normal vitamin B12 and vitamin D levels in a patient.

(Example of “normal” serum vitamin B12 levels in a highly symptomatic patient who improved with vitamin B12 shots) 

In addition, we are more concerned with B12 metabolism than we are with vitamin B12 itself.

In the case of MCV – it can be changed by iron deficiency (which is another common nutrient deficiency).

Low iron = low MCV

So you might have iron deficiency and vitamin B12 deficiency (they frequently both occur in hypothyroidism) which can make your MCV seem normal even though that’s not the case.

Homocysteine is also an inflammatory marker (15) which can be raised in cases of acute inflammation. 

So even though these tests can be very helpful they aren’t the end all be all.

My recommendation is that if you are symptomatic it is worth a trial of vitamin B12, preferably in injection or shot form.

What’s more is that even at the end of the day, some patients just need supraphysiologic doses of vitamin B12. 

That means some people just may do better with “high” serum levels of vitamin B12. 

Benefits of taking Vitamin B12

What kind of diseases and syndromes can vitamin B12 actually help?

As you might expect because the symptoms of deficiency are so diverse, the replacement of vitamin B12 can help a multitude of problems.

Benefits of Vitamin B12 shots and injections:

  • Increase energy levels (more consistent and sustained energy throughout the day with fewer crashes) 
  • Improved sleep at night
  • Improved hair growth or decreased hair loss (hair loss is multifactorial but almost always iron and B12 levels play a role)
  • Improved immune system (16) (many patients use the boost while they are acutely ill or use it to prevent getting sick around others)
  • Improved weight loss (not a direct benefit – we will go over this extensively below, but having more energy allows for more exercise)
  • Improved mood, decreased depressive symptoms, and more emotional stability
  • Improved concentration and decreased brain fog (Frequently helpful in patients with ADD-like symptoms)
  • More consistent cortisol levels in cases of adrenal fatigue

The above list is what I have observed and noticed in both patients and myself (I also use B12 shots weekly due to methylation issues that I personally carry). 

They certainly don’t represent the total spectrum of benefits that you may experience when taking B12 shots but they do cover many of the frequent symptoms that vitamin b12 patients have. 

Having used vitamin B12 extensively in my practice with great results I’ve also discovered that certain patients do much better when taking vitamin B12.

In most cases I will recommend vitamin B12 shots to patients who have any of the following medical conditions:

  • Hypothyroidism: Thyroid hormone is involved in stomach acid production which is involved in B12 absorption. 
  • Hashimoto’s thyroiditis: For reasons above + the immune dysregulation that many Hashimoto’s patients have. 
  • Depression or other mood disorders
  • Chronic pain, fibromyalgia, or chronic fatigue syndrome
  • History of Documented vitamin B deficiency
  • Gastrointestinal issues including SIBO, SIFO, yeast overgrowth, reflux, IBS or IBD
  • Peripheral neuropathy or nerve damage
  • Patients who are pregnant or looking to get pregnant

These patients represent a specific subgroup of the population with very special needs and a propensity to develop B12 deficiency that may go undiagnosed. 

If you have any of the following medical conditions vitamin b12 shots would be worth considering even for a short trial period. 

Vitamin B12 and Thyroid Function

It’s worth spending some time talking about hypothyroidism and Hashimoto’s and how they relate to B12 deficiency. 

As you may know, low thyroid can directly lead to a number of nutrient deficiencies (which you can read about here), and in order to fix the thyroid they really have to be addressed.

And Vitamin B12 is no exception.

As many as 50% of thyroid patients are B12 deficient and that creates a very special circumstance. 

The symptoms of Vitamin B12 deficiency and hypothyroidism closely overlap:

Chronic fatigue, hair loss, brain fog, decreased concentration, etc.

It’s easy to see how you can confuse the symptoms of hypothyroidism for the symptoms of Vitamin B12 deficiency.

And this happens quite often.

Many patients wrongly assume that ALL of their symptoms are due to thyroid hormone so they continually seek out higher and higher doses of thyroid hormone.

The problem is that low thyroid hormone causes low stomach acid which decreases the absorption of vitamin B12.

In addition to this problem many hypothyroid patients (again as many as 50%) also have GI issues like SIBO/SIFO.

And any intestinal issue further worsens vitamin B12 absorption making the whole situation worse.

The kicker is that simply replacing thyroid hormone is NOT enough to replace vitamin B12 levels.

Hypothyroid patients are special in that they often need both the thyroid hormone that accompanies vitamin B12 and iron (after checking labs).

Only then do thyroid patients actually start to feel better. 

Because of this vitamin B12 thyroid connection if you have hypothyroidism and you suffer from any of the above symptoms it’s worth checking your labs for deficiency and even a trial of vitamin B12 if you have “normal” labs.

B12 Shots for Weight Loss: Do they work? 

This is another big question I get all the time.

The quick and short of it is this:

Vitamin B12 shots do NOT directly lead to weight loss, however, they can be helpful in weight loss efforts due to a variety of reasons we will explain below.

Despite the fact that “weight loss clinics” give out vitamin B12 shots and fat burner shots do not mean they actually work.

I have the advantage of focusing almost specifically on helping patients lose weight by balancing hormones so I am intimately familiar with weight loss and everything that it entails. 

I have used both fat burner shots and b12 shots to help patients for a variety of reasons and I’ve never seen b12 shots by themselves help someone lose weight. 

Instead of directly leading to weight loss I think the answer is more simple:

Because so many patients are B12 deficient without knowing, taking B12 shots actually helps replace this deficiency. 

Replacing the b12 deficiency helps improve energy levels, reduces depression, and helps patients get up and moving. 

So by themselves, they don’t directly lead to weight loss, but if coupled with a comprehensive weight loss plan they can be quite powerful. 

Vitamin B12 Shots and Injections over Oral forms

Why is it that I specifically recommend B12 shots over other forms of B12, specifically oral forms like tablets/liquid and sublingual forms?

The answer has to do with absorption and dosage.

As I’ve mentioned several times above simply taking vitamin B12 by mouth isn’t enough to get it into your body or into your cells. 

In order for B12 to be properly absorbed you need all of the following to be working perfectly: 

1. Adequate amounts of stomach acid and hydrochloric acid

2. Adequate amounts of intrinsic factor

3. Functioning pancreas with adequate amounts of proteases and enzymes

4. Functioning small intestines and villi (without inflammation)

5. Proper metabolism of B12 in the body and cells

You can see that the first 4 steps all require proper function in the GI tract.

But the problem with that is how many of you suffer from SOME kind of gastrointestinal disorder?

I’m talking about any of the following:

  • Chronic constipation
  • Acid reflux
  • Irritable bowel syndrome
  • Diarrhea or loose stools
  • Acid reflux
  • Small intestinal bacterial overgrowth
  • Small intestinal fungal overgrowth
  • Inflammatory bowel disease
  • History of using acid blockers like proton pump inhibitors or H2 blockers

Just one of these conditions is enough to interfere with the absorption and the first three steps of vitamin B12 absorption (and this doesn’t include vitamin b12 metabolism). 

With as many as 20% of the population with IBS alone (17), it’s not hard to see how so many patients may be taking oral forms of vitamin B12 without any benefit.

That may explain oral and liquid forms of B12, but what about sublingual forms of B12? 

In my experience (having the advantage of treating hundreds of patients with both sublingual and shots/injection forms of B12) I can say that sublingual forms are not always rapidly absorbed and utilized by the body. 

Although it seems that physiologically it would be absorbed and utilized it seems not to be the case in the majority of patients I treat.

Something similar happens with sublingual HCG vs HCG injection.

Theoretically, there should be complete absorption but it appears not to be the case.

It probably has more to do with the utilization of the B12 vs the actual absorption. 

Intramuscular and subcutaneous injections have the advantage of being slowly absorbed over a period of time without undergoing the first-pass metabolism in the liver as supplements that are absorbed via the GI tract do.

Instead, subcutaneous and intramuscular injections are readily available at the cellular level for the tissues in which they are injected causing symptomatic relief very quickly.

What many patients underestimate is their body’s ability to both absorb and utilize nutrients and vitamins.

So consider this:

The sicker you are, the more nutrients and vitamins you need and the more energy it will take to both absorb and utilize these nutrients.

It’s a vicious cycle.

In addition, if you’ve ever been to the hospital you know how effective intramuscular and intravenous administration of medications and nutrients can be.

When you are septic with a systemic infection Doctors will always give you IV forms of antibiotics instead of oral pills, that’s because more is bioavailability and action.

The same is true for strep throat infections.

Have you ever had a penicillin or another antibiotic injection? It works much more rapidly than taking oral pills.

This same principle is applied to nutrient and vitamin deficiencies like vitamin B12 deficiency.

Vitamin B12 Injections and Dosage: How much do you need? 

So how much vitamin B12 do you need if you use shots or injections?

Well, you actually need much less than oral forms of B12 including sublingual preparations.

This is another testament to the fact that subcutaneous and intramuscular injections are more rapidly absorbed and utilized!

Generally, the dosage for B12 in oral forms ranges from 1,000-5,000mcg taken each day.

Compare that to the dose of methylcobalamin used in the shot and injection form which is 5,000mcg taken every 7 days.

So oral forms you need to take 7 times the dose (and it needs to be taken daily) and even at these doses, the oral forms don’t necessarily impact symptoms.

Another advantage of IM and subcutaneous injections is that they provide a more stable release of nutrients into the body (18). 

That means you get a constant release of vitamin B12 into your body which is sustained throughout the week. 

This sustained release of vitamins helps prevent crashes that can occur by taking oral medications or especially if an oral dose is skipped or missed.

So where do you inject vitamin B12?

I have successfully used both intramuscular and subcutaneous routes of administration for methylcobalamin.

More recently I prefer the subcutaneous route because you can use insulin needles + syringes and it’s less painful for the injection plus the absorption and results are similar to the intramuscular route.

Where do you inject into your body?

  • Intramuscular route: Mid-thigh, deltoid area, or glut region (thigh is the easiest if doing it on yourself)
  • Subcutaneous route: Same locations but you can also include areas like the abdomen

How frequently do you inject into your body?

Generally, every 7 days is recommended to start, but occasionally I will increase or decrease the frequency depending on how the vitamin is tolerated. 

Methylcobalamin vs Cyanocobalamin

Not all forms of vitamin B12 are created equal. 

Like many other nutrients – I’m looking specifically at you magnesium – some forms are cheaper and far less effective than others.

This is especially important when it comes to vitamin B12.


Because as many as 40% of the population has issues with B12 metabolism due to genetic mutations at the MTHFR locus.

What this means is that certain forms of B12 can get “caught” up during the metabolic process which means they aren’t available to be used by the body and in some cases can make patients feel worse.

In patients who have this abnormality providing the body with excess methylation groups (which comes in methylcobalamin) helps to keep the B12 in the body longer and helps the tissues utilize the B12. 

So there is a big difference in terms of the effectiveness of B12 that depends on what is bound to the cobalamin infrastructure. 

Whenever possible avoid the cyanocobalamin forms of B12 (you can easily check which form your B12 comes in by looking at the active ingredients section on the back of your vitamins) and take preference for methylcobalamin. 

What’s interesting is that many “weight loss clinics” and even physicians use cyanocobalamin when giving patients injections or shots.

Even though giving shots and IM B12 is superior to oral forms, if you are using cyanocobalamin you still aren’t getting the best results.

In this case, it’s very important to use methylcobalamin for injections and shots.

This will allow even better results in terms of symptomatic relief.

This also may explain why some people who have had B12 shots elsewhere seem to improve more when I give them methylcobalamin instead of cyanocobalamin. 

Frequently Asked Questions about Vitamin B12 Shots

After reading this you may have more questions about using vitamin B12 shots and injections. 

I’ve provided these frequently asked questions sections to answer those questions.

This information is based on my experience in treating hundreds of patients with high-quality, pharmaceutical grade B12, and my results.

Where can I get the right form of B12 shots?

Finding high-quality methylcobalamin B12 shots can be difficult unless you are looking in the right place. 

You can usually find them locally if you look for an integrative physician’s office but make sure they are the following:

  • Methylcobalamin 5,000mcg dosage (don’t get 1,000mcg dosage forms or you’re only getting 1/5th the dose)

Frequently offices may try to give out 1,000mcg dosages of cyanocobalamin because it’s cheaper – you will want to avoid this type of dosage and form of B12. 

They also need to be shipped on ice and should preferably include needles + syringes.

Remember not all forms of B12 are created equal. 

Will B12 shots work for me?

It’s hard to say for sure.

In my experience, about 60-70% of patients benefit from taking B12 shots in some way.

The most common benefit is more sustained energy levels without crashes throughout the day.

If you’ve been on high-quality B12 shots previously and didn’t notice a benefit then they aren’t likely to produce significant results in your body.

I generally recommend B12 shots as part of an entire and comprehensive treatment plan instead of being used in isolation, but many patients swear by using them alone.

At the end of the day remember this:

There is very little risk to using B12 shots and the benefits may be tremendous. When in doubt it is worth a trial especially if you’ve tried oral forms of vitamins and B12 that haven’t worked. 

Where do I inject the B12 shots?

It depends on the length of the needle and whether or not the injection is subcutaneous or intramuscular.

I prefer to use the subcutaneous route which means the needle is much smaller and can be used in more places on the body: abdomen, thigh, gluteal region, and shoulder/deltoid region. 

If you use intramuscular you are limited to using a place in the body like the thigh or deltoid (shoulder area).

Does it matter if the shots are subcutaneous or intramuscular?

Subcutaneous injections tend to be better tolerated (have less pain) and don’t go as deep into the tissues so trauma and bleeding are less.

Subcutaneous injections increase compliance and have similar efficacy to intramuscular injections.

In the end, it doesn’t necessarily matter but comes down to a matter of preference. 

How often can I use B12 shots?

I generally recommend 5,000mcg once per week, but sometimes patients can decrease the total dosage and increase the frequency of shots.

So, for instance, using 3,000mcg every 3 days may be better tolerated and provide a more sustained energy level in some patients. 

I generally base my frequency on a combination of labs, patient symptoms, and how much the patient is improving.

Can you get too much B12 in the shots?

Vitamin B12 is a water-soluble vitamin

That means it can safely be eliminated in your bloodstream and filtered through your kidneys (as long as your kidneys are functioning normally). 

High toxicity and hypervitaminosis come from high doses of fat-soluble vitamins because these vitamins can be deposited into fat cells and stay in the body longer.

Any excess vitamin B12 is simply urinated out of your body.

It’s common for patients to have high serum levels of vitamin B12 after vitamin B12 shots and injections which, to an untrained eye, can make it seem like you are getting too much vitamin B12. 

This isn’t a concern because the serum level of B12 doesn’t necessarily correlate with cellular levels of B12 due to metabolic issues, etc.

So in these cases, uninformed Doctors may express concern over serum levels when it isn’t appropriate.

In fact, during treatment and in severely deficient patients, I like to see serum vitamin B12 levels > 1,000 (which is technically “high” by lab reference ranges). 

Bottom line:

It’s almost impossible to become toxic on vitamin B12 unless you have kidney issues.

Are B12 shots safe?

Yes, vitamin B12 shots are safe to use.

The biggest risk comes from the injection.

Whenever anything is entering into your body there is a small risk of bleeding or infection.

In over 1,000 vitamin B12 shots, I’ve never seen anyone have any issues with either, but there is a theoretical risk factor for both.

The most common side effect that I see are positive side effects.

Negative side effects may include a paradoxical decrease in energy levels (most likely due to detoxification from methylation) or slight pain at the injection site which diminishes over 5-10 days.

All in all, B12 shots are both safe and efficacious.

How big are the needles?

When using the subcutaneous route the needles really aren’t that large. 

You can see an example below:

two needles on top of each other to illustrate the reduced length of the needle on top.

Subcutaneous needles are insulin syringes and the length of the need varies from 6mm to 12mm which is less than 1 cm. Remember that 2.5 cm = 1 inch, so we are talking significantly smaller than 1 inch. 

In very lean individuals you can actually use insulin syringes to reach the depth of the muscles if you push hard enough on the skin.

Can I use sublingual B12 or oral forms of B12 instead of shots?

You are certainly welcome to use whatever form of B12 works well for you. 

If you are currently using sublingual or oral forms of B12 and you are getting symptomatic relief then I wouldn’t recommend changing up your method of administration.

But if you are still experiencing symptoms or you have any of the medical conditions listed above, then a trial of B12 shots is certainly worthwhile.

In these situations, I recommend B12 shots as first-line therapy over oral forms.

If you would prefer to start out with sublingual forms and oral B12 then I recommend this supplement.

Are there any disadvantages to using B12 shots? What are the risks?

B12 shots are generally safe as long as proper precautions are taken for the injections. 

Any negative side effects come from the very small risk of bleeding or infection after the shot.

In general, risks are very low but do occur occasionally. 

Disadvantages of using shots include some pain at the injection site.

Disadvantages of using oral forms: inferior absorption, inferior cellular activity, require high compliance with daily dosing.

The right choice over oral or shot form depends on you and your situation.

Can I use both B12 shots and oral forms of B12?

I have many patients who use both oral forms with B12 shots and injections.

Some patients feel that B12 shots provide a very sustained and consistent energy level throughout the week but like to supplement and augment this effect with oral forms on particularly stressful days.

It is safe to use both forms simultaneously (provided you have functioning kidneys). 

How long do I need to be on B12 shots?

This depends on your personal situation, how low your vitamin B12 levels are intracellularly, what kind of medical conditions you have, and how much improvement you get from the B12 shots.

I always recommend a series of 10 shots taken every 7 days over 10 weeks.

This allows for a sufficient trial length and will allow for enough B12 to make a difference over a sustained period of time.

Most patients who experience significant relief will notice it almost immediately.

Many patients experience significant improvement in symptoms within days of the first shot.

Others don’t notice a difference unless they forget to take their shot after 7 days, or they feel the effects wear off after 3-5 days.

How you react largely depends on your specific situation.

After 10 weeks or injections you have several options:

1. Recheck blood work including MCV, hgb (if anemic), serum B12, and homocysteine. 

You should be able to see your MCV increasing, your homocysteine dropping, and your serum B12 level increasing. 

These are indications that your B12 is working.

You can simply base your length of treatment on these values until you get to the optimal range if you’d like.

Alternatively (and this is the approach I take for many patients), if you are experiencing significant symptomatic improvement then you can just continue to take the B12 shots indefinitely.

I have many patients who feel so great with B12 shots they simply continue taking them each week regardless of what their labs show.

Take whatever approach works best for your situation.

If you are unsure how to proceed you can always take a series of 10 shots and then monitor your symptoms after you are done to see if they get worse on weeks 11-13.

If your symptoms worsen then you can simply go back on the B12 shots.

Are there side effects to B12 shots?

Side effects should primarily be positive:

Meaning an increase in energy levels, decrease in crashes, improvement in hair growth (or decrease in hair loss), improved concentration, decreased depression, etc.

Negative side effects occur rarely and include a decrease in energy levels (which happens in about 2-3% of my patients).

For patients who experience a paradoxical decrease in energy levels, it doesn’t mean you should stop taking the B12 but instead decrease your dose by half (so take 2,500mcg every 7 days) or simply take 5,000mcg every 14 days instead.

This is usually an indication that you have a methylation defect and need to slow down on the amount of B12 you are taking.

Should I get labs before I use B12 shots?

You don’t necessarily have to get labs as a baseline if you are symptomatic (symptoms listed above).

If you prefer to get labs as a reference range you can use the list of labs above.

Will B12 shots interfere with my prescription medications?

Actually, it’s generally the other way around.

Many medications actually DECREASE your vitamin B12 levels and are more likely to make you deficient.

Medications in this category include: Metformin, H2 blockers and PPI (proton pump inhibitors) used to block acid production in the GI tract. Nitrous oxide can also deplete B12 levels. 

As long as you take the B12 via shot form or injection form it should not have an effect on any other medications you may be taking. 

Can I get B12 shots from my regular Doctor or Primary care physician?

Generally, primary care physicians are not used to using the proper form or dose of B12 levels. 

We still have physicians using vitamin D2 instead of D3 when we have studies showing (19) D3 to be far more efficacious than D2. 

Vitamin B12 is no different. 

You can try to use your primary care physician as long as you use the recommended settings above but beware:

Most physicians are not used to dosing vitamins and are very unfamiliar with them in general.

This leads to underdiagnosis and mismanagement.

Whenever possible avoid getting B12 shots from your PCP unless they also have some background in integrative medicine.

When should I take the B12 shots?

Because some patients do experience a significant increase in energy levels after taking even their first shot it is best to use it first thing in the morning. 

That way the sustained energy levels will not interfere with your bedtime routine or keep you up.

Even using this strategy some patients (minority) do have issues with sleep for the first 1-2 days after each injection.

This can be combated by simply reducing the dosage by half and increasing the frequency of the injections

B12 shots should be taken on the same day of each week and every 7 days. 

So something like every Sunday morning should work well for most patients.

Remember consistency is important.

Does B12 need to be refrigerated?

Yes and B12 should be shipped with an ice pack to maintain temperature levels.

All B12 shots shipped from my office come with ice packs and instructions for refrigeration upon arrival.

Will insurance cover B12 shots?

Unfortunately no, insurance will not cover B12 shots.

When it comes to vitamins and nutrients you are usually on your own even though there is significant evidence that they provide relief and can help many patients.

Recap & What to do Next

If you have any other questions please post them below and I will provide a detailed answer to this frequently asked question portion. 

I strongly believe in the use of B12 shots because I’ve found them to be so helpful in many situations. 

No, they aren’t miracle supplements by themselves, but if used appropriately and as part of a comprehensive treatment plan they can be very powerful. 

If you have persistent, chronic fatigue, decreased hair loss, depression (or anxiety) or suffer from any of the other symptoms listed above you may benefit from B12 shots.

Now it’s your turn:

Have you used B12 shots successfully in the past?

Did they work for you? why or why not?

Do you have thyroid problems, if so have you tried B12 shots?

Leave your questions and comments below!

#1. https://www.ncbi.nlm.nih.gov/books/NBK6561/

#2. https://www.ncbi.nlm.nih.gov/pubmed/18655403

#3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263877/

#4. https://www.ncbi.nlm.nih.gov/pubmed/25902009

#5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1570488/

#6. https://www.ncbi.nlm.nih.gov/pubmed/15681626

#7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3856388/

#8. https://www.ncbi.nlm.nih.gov/pubmed/15029091

#9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2294086/

#10. https://www.ncbi.nlm.nih.gov/pubmed/8435917

#11. https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/

#12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1570488/

#13. https://www.ncbi.nlm.nih.gov/pubmed/11553056

#14. https://www.ncbi.nlm.nih.gov/pubmed/15831132

#15. https://www.ncbi.nlm.nih.gov/pubmed/11553056

#16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1905232/

#17. http://emedicine.medscape.com/article/180389-overview

#18. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4494621/

#19. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3349454/

benefits of using b12 shots pinterest image.

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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 80,000+ people have used them over the last 7 years. You can read more about my own personal health journey and why I am so passionate about what I do.

P.S. Here are 4 ways you can get more help right now:

#1. Get my free thyroid downloads, resources, and PDFs here.

#2. Need better symptom control? Check out my thyroid supplements.

#3. Sign up to receive 20% off your first order.

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61 thoughts on “B12 Shots Benefits: Weight Loss, Energy & More”

  1. Dr Childs ,

    I had mercury poisoning and B12 shots saved my life along with my Dr who detoxed me from mercury . I was soooooo sick , seemed each day was so hard to get through . But thank God , I had a Alternative Dr who kept searching until he found the root problem and detoxed me .

    Thank you ,

    • Hey Marc,

      I just realized that the greater than and less than signs weren’t showing up on the previous article so I edited it.

      Ideally your MCV should be > 80 but < 92. But this can't be used in isolation because other nutrients/medications can alter MCV levels, so use it in conjunction with serum B12 levels, homocysteine and MMA. Quote from article: Mean corpuscular volume (MCV): Your MCV should be less than 92 but greater than 80. This test is part of the CBC (which almost every Doctor will order) and tells you how large your red blood cells are. A high MCV is very sensitive for B12 and folic acid deficiency. Beware that iron deficiency can artificially lower your MCV value and mask vitamin B12 deficiency.

      • Yes, WordPress mangled the portion of my comment in which I quoted from the sublingual-b12 article.

        In light of your response confirming that you want to communicate that MCV should be between 80 and 92, this b12-shots article has a mistake where it claims that MCV should exceed 92. My quote of the error appears correctly above. You can find the error by searching in page for “92”.

        • Sorry for the confusion but thanks for pointing that out and I just changed it to read should be less than 92 in this article.

  2. So we can get LDN and Vitamin B12 shots from you? How do I get started? What would be the cost of these supplements and your own fees? Thanks!

    • Hey Debbie,

      I’m not accepting any new patients so you can’t get the LDN from me. You will need to find a provider near you who knows how to dose and prescribe LDN.

      • What are LDN and fat burner injections? Where could I go to to get started on them and B-12 injections? I live in a city called Lancaster, California anything near by me?

        • Hi Tashana,

          LDN is a medication that is taken by mouth while B12 injections are injections which contain B12 and other vitamins to help with weight loss. Doctors can prescribe both of these therapies but you’ll need to find someone near you to do that. I don’t know anyone in that area but I’m sure you could find someone with some research.

    • Hello Dr Childs,

      Can we purchase the Vit B 12 shots from your website, the link referred to above is not on the article.

      Many thanks for your wonderful website and advice

  3. Thank you for the great article. I have been taking fat burner injections once weekly and 5000mcg of B-12 daily. It has been 2 weeks and I have lost 15 lbs. Needless to say I am thrilled. It works!

  4. I received a B-12 shot today for the first time. I do not notice much difference. Although I am not that tired in the afternoon. Like I usually am. Your product 5000 seems interesting to me. My hair has thinned .
    Where does your vitamin b-12. come from.?
    Could you provide a price list ? Syringes? I would like to try it every Sunday. I am trained.

    Thank you

  5. I can’t find the link to purchase B12. My doctor gave me a script for B12 injections. (visit him out of state) but I have been to pharmacies who have no clue, could only find B12 for poultry injections on the internet. Please inform me if I can get B12 from you! My doctor is in accord with most of what you
    have written. The Riordan Clinic in Wichita, Kansas.

  6. Great article doc! What dose would you recommend for pediatrics. I know this can vary but what ranges would you recommend for each age group. Thanks!

  7. First of all thank you so much for this great article. I have been strugling with all of these underlisted symptoms and can’t wait to start with the B12!

    Unfortunately the link to purchase the B12 injections is not showing. Is there any way to send this link to my e-mail?

    Kind regards

  8. I need B-12 shots for Pernicious anemia. I have a prescription but the pharmacy only has cyanocobalamin. It doesn’t help at all, just makes me more fatigued! Can you help me? I can give you a prescription from my doctor!

  9. My dr recommended B12 shots as I was deficient (according to labs on the very low end) I haven’t noticed any increase in energy either and have gained weight like crazy after starting them. I don’t eat anymore and had started an exercise routine so the weight gain is very frustrating. Do you have any suggestions?? Is this normal?

    • Hi Heather,

      That would definitely not be considered normal. You will want to have your hormones checked as well as your B12 checked to determine what the issue is.

  10. Where can I get the correct vitiman B12 at for the shots? I can give myself so I need to order a bottle of it to try.
    Vanessa Cudney

  11. May I have the link for source of B12 shots you make mention of in your article? Thank you.

    “f you are looking for a safe and reliable place to buy B12 shots you can use the link below to get 10 vitamin B12 injections (in methylcobalamin form) including small insulin needles + syringes which are prepackaged and ready to be used.”

    • Hi Bob,

      B12 shots are only available via prescription medication now so the link is no longer working. Sorry about that!

  12. Great article, Dr. Childs. Thanks for posting and inviting us to comment and ask questions.

    I am homozygous for the MTHFR gene. After years of experiencing neurological symptoms, it was a dietician who ended up being the one who diagnosed me. (Not all of the neurologists). Whether or not the lack of vitamin B has been the main cause all these years, it has undoubtedly played a part.

    My question for you is dosing of injections. My doc who is prescribing it doesn’t have a lot of experience with this, so not sure if what they have prescribed is accurate. They started me off with one injection per day x 7 days, then 1 x week for 4 weeks, then 1x month. I’m also taking oral folate a few times a week (not every day). Does this seem like accurate dosing for the injections? Or, would 1x a week still be best?

    Thanks for the help.

  13. Tricare pays for my Vitamin B12 shots. Are you saying they wont pay for yours B12 because your not a pharmacy? If that’s the case you need to make it clear to people who can’t afford your B12 but need it of any kind or even lower dosages can get a prescription for it. Whether it’s on ice or not. I’m writing this without even knowing how much you sell your for. It may be affordable for all classes of people and not just the higher wage people.

    As a Dr you should make that clear. That’s what you’re in the business to do is help people get well not keep them sick.

    • Hi Louis,

      Perhaps what I wrote was confusing but I don’t sell B12 shots. When I wrote the article I was unaware of any insurances which cover B12 shots, it’s possible that that has changed, though! Thanks for sharing the fact that tricare is willing to cover it. It’s also worth pointing out, though, that even if they do cover it they may only cover cyanocobalamin instead of methylcobalamin which does matter for some people.

  14. Amazing article. If I wanted to do a daily subcutaneous b12 using an insulin syringe what would I draw into the syringe? My wife and I are very interested in this.

    • Hi Bill,

      Glad you found it helpful. The amount that you use depends on the concentration of the B12 you are trying to draw up. It should tell you how many mcg exist in each milliliter of the solution. If you have a 5,000mcg per ml concentration then 1 ml would provide you with 5,000mcg of B12. 1 ml = 100 IU on an insulin syringe.

  15. Where can I find the methylcobalamin? We have called several pharmacies in our area and none seem to have it. Thank you for your blog posts they are incredibly informative and helpful!

    • Hi Sandra,

      You should be able to find it at pretty much any compounding pharmacy. These are different from regular run-of-the-mill pharmacies.

      • Hi Dr. Childs – Since you made this statement in your article – “Whenever possible avoid getting B12 shots from your PCP unless they also have some background in integrative medicine. “​- What do you recommend for the method of getting the injections?

        • Hi Lindsay,

          You can still get them from your PCP provided they use the right type and dose of B12 (methylcobalamin or hydroxycobalamin). You can also sometimes find them at weight loss clinics but this is hit or miss.

  16. I have used in the past hidroxocobalamin shots, once a week, I am 68 years old and have been recently diagnosed hypothyroidism. I live in Mexico and methylcobalamin shots are not available. I notice when I get the shots, I have more difficulty falling asleep.

  17. Hi, You mention in your article as to where I can order the B12 shots, but I can’t seem to find that. Would you be able to give me that information please


  18. Hi, You mention in your article as to where I can order the B12 shots, but I can’t seem to find that. Would you be able to give me that information please


  19. Greetings:

    Dr. Childs,

    I cannot find on your website where I can order B12 shots. Would you advise please?
    Thank you,

    • Hi Natasha,

      Unfortunately, that option is no longer available as B12 shots now require a prescription in order to obtain them.

  20. Dr Childs,
    Thank you so much for such an informative article! It’s difficult to find any reliable information on B12 dosage. My question: Do you think injecting 1200 mcg per day for 60 days is too much, too little, just right? Meaning, does most of it get absorbed or excreted out? I feel great on 1200 mcg per day, but I’m thinking may be it’s too much and may be it’s more beneficent to follow YOUR regiment of 5000 mcg every 7 days? Or does it even make a difference? I don’t have any underlying illnesses, deficiencies or conditions (not that I know of). Thank you so much again!

    • Hi Lara,

      I’ve spent some time looking and I’ve never been able to find a case of B12 toxicity with B12 supplements as long as the kidneys are functioning. I can’t give you specific recommendations but I can tell you from personal experience that I’ve used as much as 10,000mcg in a week without any issues.


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