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Guide to Vitamin B12

Guide to Vitamin B12


Vitamin B12 shots.. You might've heard of getting this essential vitamin in the form of a shot from a friend or neighbor. But, what benefit is the shot going to provide you which a vitamin supplement won't? And, why do those who swear by Vitamin B12 shots, believe them to be so potent? Whether it's for weight loss, increased energy levels, to help you get through a tough workout at the gym, or simply get all essential vitamins, taking these shots is truly beneficial.

If you are new to the concept of B12 shots, how they work, what they'll do for you, or have any other questions, this is your ultimate guide. So, let's begin by discussing what they are used for and what they will do for you. Some things we will discuss as it pertains to B12 shots include:

  1. Who should take them and how to safely purchase Vitamin B12 shots to ensure the highest quality ingredient base.

  2. The benefits you will notice upon taking these shots.

  3. Why B12 shots outshine their sublingual tablet form of the vitamin.

  4. How you can determine if the shots will work for YOU, and how to inject the shots safely.

  5. What dosage you should be ingesting, and which form of Vitamin B12 is right for you (which is an extremely important point).

We'll further discuss how B12 shots can help you with increased energy levels, help you shed those last 10 lbs, and generally put you in a better mood. Of course, they are beneficial for most people. This of course comes with the caveat that they are the highest quality, purest Vitamin B12 shots available. In fact, if you aren't getting the right form of the shot, this can make all the difference as to whether you will experience the above listed benefits, or feel nothing at all.

Read more about Vitamin B12:

The Benefits: What Will B12 Shots do for you?

Vitamin B12 is something we're all familiar with; it is that vitamin we take to give us the burst of energy when we're fatigued. If you read any food or drink label which claims to give you the "boost," or help "kick the mid-day drag," it is likely that B12 is one of the first ingredients you'll see on the label.

It does so much more than gives you that boost of energy after noon rolls around at the office. In fact, it's critical to many cellular functions in your body; and, even though its contained in some many food/beverage products, it's highly likely you still aren't getting enough!

For B12 to benefit your system, it must go through a series of steps to be fully absorbed in the GI tract. Many hormonal imbalances, including thyroid imbalances, can hinder the absorption rates greatly. So, even though your diet is telling you that you're giving it enough, due to the limited absorption rates, you truly aren't getting enough. This becomes a problem further down the line for those who don't properly metabolize B12 (in lower quality forms), because of the MTHFR gene. Approximately 40% of the population suffers from this issue.

Back to that pesky thyroid discussed above. Those suffering from hypothyroidism (slow metabolism), suffer from B12 deficiencies. Studies show approximately 40-50% of individuals who suffer from hypothyroidism are deficient. Metformin. Ever heard of this medication? Well, it's just one of the many medications which can further cause absorption problems in the B12 category. Many medications can deplete your levels of Vitamin B12, which is another reason to consider supplementing B12, outside of the food/beverages you are consuming it through.

So, should you be scared or concerned? Yes and no. It's simply to give you a little idea as to why you are deficient in the vitamin, and to bring light to why you should consider supplements to help increase absorption rates. The how is also very important That is, HOW you take the Vitamin B12. For those suffering from GI Issues (GERD, IBS, reflux, etc.) oral forms of B12 are a no-no. And yes, sublingual tablets fall in that category.

This is just one of the many reasons people claim that taking shots truly makes that difference, and gives them the energy they weren't feeling prior to using this supplement form. So, what will indicate whether you should be taking the shots?

The symptoms: Are you B12 Deficient? 

Blood work isn't the best way to determine deficiency levels. This is true with many other vitamin and mineral deficiencies you may suffer from. Many nutrients occur INSIDE the cell, so serum or blood testing will only give you an indication (not a real value) of availability. Further, this is assuming everything else (cellular, enzyme, and receptor activities) are functioning normally. So, there are other means to determine whether deficiencies exist.

Because Vitamin B12 has several cellular actions, symptoms run the gamut in individual sufferers. Some symptoms include:

  • Fatigue (chronic) and low energy levels.

  • Macrocytic anemia or shortness of breath.

  • High MCV or neurological changes (which can mimic dementia).

  • Mood disorders, anxiety, depression.

Individuals may also suffer from brain fog or have difficulty concentrating. Skin changes which include hyperpigmentation, and hair changes (including loss) are all tell-tale signs of a deficiency. If you've noted one or more of the above, it might be a sign you suffer from a deficiency.

Have you tried sublingual forms or tablets? Still suffer from these symptoms? Regardless of the situation you're in, the fact that a high number of people in the population suffer from a deficiency, is something alarming, which can have many negative, adverse side effects. How is it possible that approximately 40% of patients suffer from this deficiency? The answer: physician and patient complication of the issue. So, let's further explain this theory.

Checking for a deficiency: Diagnosis of B12 Deficiencies

Improper diagnosis is the leading problem in determining whether an individual is deficient. Think of the last time your doctor ordered a panel test for Vitamin B12 deficiencies. Or, when did you last request for them to order these labs? The simple fact is that most doctors simply don't test this often.

Many doctors are also using a "standard range," provided by labs, in the event they do run a screening. This is used instead of the "optimal" range which is far more accurate. Most doctors will tell you that you don't suffer from a deficiency and that you don't require any form of supplement to increase ingestion levels.

Many physicians seem to be following the trend that vitamins and minerals simply aren't all that important in devising a treatment plan for their patients. This is however contrary to the fact that including the right vitamins and minerals is integral to treating a patient. Even with these facts in mind, serum or blood test screenings still don't provide the most accurate reading when it comes to checking Vitamin B12 levels.

What is the best way?

The Lab Test Route -

If you are using lab tests to check for deficiencies, they should:

  • Check serum levels - These should be in the top 75% percentile of the reference range. Those with mid-range to high levels still might have MCV and high homocysteine levels, and B12 supplements can benefit them.

  • MCV - Mean corpuscular volume should fall under 92. The test determines average size of red blood cells, which means the higher the level, the higher your blood cells. Both B12 and folic acid deficiencies are the leading reasons the cells are so large. An iron deficiency can also throw off your MCV readout.

  • Homocysteine Levels - These should be below 9-10 range. High levels are a marker of a B12 deficiency; further, high homocysteine levels are a marker of patients who are higher risk for stroke or cardiovascular disease.

  • Urinary organic acid & methylmalonic acid tests - This is a good way to diagnose other deficiencies. For B12 screening this is a good indicator as to whether a deficiency exists.

When did you last have these tests conducted, or when was the last time you doctor reviewed the "optimal range," values? The answer is probably never. But your doctor still relies on science to tell you that you aren't deficient. What further complicates the issue is that even these complex tests listed above aren't 100% accurate either. B12 serum levels indicate what's found in your serum, but they don't determine what's in your cells, which is where B12 action occurs.

Another caveat to the above is that what we are really concerned with is the B12 metabolism not the vitamin levels themselves. Let's take MCV for example; an iron deficiency can alter your reading. Low iron levels mean low MCV levels. This means an iron and Vitamin B12 deficiency may be present; this can cause MCV levels to appear normal, even though they aren't. Homocysteine is also an inflammatory marker, so those who suffer from acute inflammation will have increased levels.

Yes, these tests are helpful, this doesn't make them the almighty solution to testing deficiencies. So, what's my suggestion? If you are symptomatic, it's at least worth trying a B12 injection to increase Vitamin levels. What further complicates matters is that some patients simply require supra-physiologic doses of the vitamin. This basically means some people simply do better with high serum levels.

What are the benefits?: Why you should take B12 shots

Does Vitamin B12 help prevent or treat diseases or syndromes? The answer is yes. Remember the symptoms above? Because they are so diverse and because there are so many, it can help with several problems. So, what are some of the benefits of using injections?

  • Increased energy - This means fewer crashes, and more consistent energy levels throughout the day.

  • Suffer from insomnia? You'll experience better night's rest with increased Vitamin B12 levels.

  • Losing your hair? You will experience regrowth, or at least stop the hair loss which has taken place.

  • Improved immune system functions. In fact, several patients use this while they are ill, in order to prevent getting sick when around other people.

  • Lose the weight. Okay, you aren't magically going to drop 20 pounds. But, increased energy levels will contribute to helping you get to the gym, exercise, and improving your diet. So yes, indirectly it will help with weight gain issues.

You won't feel depressed, your mood will naturally improve, and emotional mood swings will cease. Decreased brain fog and the ability to concentrate on different topics (for longer periods of time) are also improvements you will notice when you take B12 shots. And, for those who suffer from adrenal fatigue, you will notice consistent cortisol levels after you begin using the shots.

Not only have I noticed the above with patients, but also myself. Because of methylation I use the shots weekly as well. Of course, this isn't an all-inclusive list of the benefits you'll experience, but these are related to a number of symptoms that most sufferers of the deficiency complain of.

With many years of experience in my practice, I've learned that patients who take the Vitamin B12 shots typically do much better in treating these symptoms, than those who aren't supplementing. So, who do I recommend the shots to? Patients who suffer from:


  • Hypothyroidism (slow metabolism) - Since the production occurs in the stomach, where B12 absorption occurs, deficiencies are common.

  • Hashimoto's thyroiditis - The reasons above alongside immune dysregulation are issues which patients who suffer from this condition deal with. B12 shots help.

  • Those suffering from mood disorders and depression.

  • Individuals who suffer from Fibromyalgia, chronic pain, or chronic fatigue syndromes.


I also refer patients who suffer from histories of deficiencies, GI issues, and peripheral neuropathy or nerve damage, to use the shots. Women who are, or are looking to get pregnant, also benefit from the supplement.

These are individuals who fall into a certain sub-group which suffers from the deficiency and has a specific need. If you suffer from any of the above, it is worth speaking to your doctor, and discussing if B12 shots can help you.

The Thyroid: How it works with Vitamin B12

Hashimoto's and hypothyroidism are two conditions worth discussing a bit further. Especially in relation to B12 deficiencies. Those who have low thyroid levels are prone to deficiencies in other areas as well; to fix the thyroid, these problems must be addressed. This is also true with Vitamin B12.

Approximately 50% of individuals who suffer from a thyroid deficiency are also deficient in B12 levels. The reason this is an issue is because the symptoms of both deficiencies greatly overlap one another. These include: the mood swings, brain fog, lack of concentration, and a few others.

It's easy to note why the symptoms and deficiencies can be confusing; it's even easier to see why many doctors don't diagnose both deficiencies. Several patients simply believe ALL symptoms are because of their thyroid condition, and this usually is not the case. Low thyroid levels equate to low stomach acids. And, this decreases B12 levels because absorption occurs in the stomach. Further complicating issues is the fact that many hypothyroidism sufferers also suffer from GI problems. Therefore, more intestinal issues, means even worst B12 absorption rates in the stomach.

Simply replacing the thyroid hormone won't do the trick. Hypothyroid sufferers are unique in that they often require medication to treat the thyroid, as well as B12 supplementation. This is the only way patients will truly feel better. So, if you do suffer from these conditions, and suffer from hypothyroidism, it's worth checking out your labs. And, it's worth understanding the "normal" reading of those labs, to determine if you should be supplementing.

Shed those pounds: Will B12 shots help with weight loss?

I get this question often. The quick answer is: Vitamin B12 shots WON'T directly equate to weight loss. But, they can aid you in your journey to losing the weight. Just because weight loss clinics give B12 shots as a fat burner doesn't mean you'll magically lose 20 pounds. I am familiar with what weight loss requires, as I intimately help patients lose weight through balancing hormone levels.

I've relied on fat burner as well as B12 shots for several reasons. I've never witness the B12 shots work on their own. They don't directly lead to weight loss, but they do target the deficiency problem which so many patients suffer from. By replacing the deficiency, energy levels go up, patients aren't as depressive, and they naturally get up and start moving. When coupled with exercise and proper diet, the B12 shots can help you lose those last 10 pounds you've been trying to get rid of.

Injections vs Oral form: Why Choose B12 Injections

So, why do I rely on the shots, over sublingual or tablet forms of Vitamin B12? In short, absorption and dosage are the main reasons. I've discussed in depth how simply taking a tablet doesn't mean your body naturally absorbs the vitamin. For proper absorption to occur, these factors must work together.

  • Hydrochloric and stomach acid levels must be at the proper levels.

  • An adequate amount of the intrinsic factor must be in place.

  • A fully functioning pancreas (with proper levels of enzymes and proteases).

  • A functioning small intestine which isn't inflamed.

Proper B12 metabolism also must occur. So, as noted in the first 4 factors, proper GI functionality is essential. But, as mentioned above, there are many individuals who suffer from some form of gastrointestinal condition. These can come in the form of: acid reflux, IBS, chronic constipation, diarrhea, loose stools, and many others.

If you suffer from even one of these conditions, this will interfere with absorption rates. Approximately 20% of the population suffers from IBS alone, so you can understand how such a high number of patients will have a problem absorbing the Vitamin through a sublingual or tablet form. I've treated hundreds of patients with both sublingual and shot forms; I can confidently say that those who use sublingual, don't absorb at as high a rate as the patients which use the shot form of the Vitamin B12. Sure, physiologically it seems normal absorption would occur, however in my practice, this hasn't been the case.

Sublingual HCG and injection HCG is another example of how absorption rates greatly differ in both forms. In theory, full absorption should occur with both; but in practice, this isn't always the case. It is likely that the issue falls in utilization as opposed to absorption. Both intramuscular and subcutaneous injections are slowly absorbed over time. This is without undergoing the first pass metabolism in the liver which are eventually absorbed in the GI tract.

Rather, with subcutaneous and intramuscular injections which are readily available at the cellular level, the tissues where injection occurs results in immediate symptomatic relief. Patients don't understand the body's ability to utilize and absorb vitamins and nutrients. So, let's consider this example. The sicker you are, the more nutrients and vitamins you need. Further, the more energy you will require to absorb these vitamins. It becomes a vicious cycle.

For those who've ever been hospitalized you probably understand how intramuscular and subcutaneous IV administration of medication works. Doctors rely on IV, rather than tablet forms of many medications. This is because of higher bio-availability levels. The same goes with strep throat infections. Penicillin and other antibiotics work far better in the injection form, over the pill form. When it comes to B12, the same theory goes.

Dosage Requirements: How much b12 do you need?

The answer is that you will require far less than you take with the sublingual version. This is yet another testament as to how much greater the absorption rates are in the shot form. In the oral form, dosage ranges are from 1000 to 5000 mcg daily. This is in comparison to the methylcobalamin used in the shot, which only requires 5000 mcg every 7 days. This means that the oral form requires 7 times as much, to produce the same benefit.

Higher stability release of nutrients in the body is yet another benefit of the shot form of Vitamin B12. This means a constant release throughout the week occurs. This helps prevent crashes which occur if you skip or miss taking an oral supplement. You can use both subcutaneous or intramuscular points when injecting the B12. However, I prefer the subcutaneous route because it is less painful and insulin syringes/needles can be used. Absorption rates are also similar in both injection methods.

What are the injection points:

1. Intramuscular - You can choose mid-thigh, the deltoid area, or gluteal region.

2. Subcutaneous - These are similar areas, but you can also inject in the abdomen region.

You will generally begin injecting every 7 days. However, increases or decreases should be made accordingly to patient's needs.

Methylcobalamin b12 vs Cyanocobalamin b12

Not all B12 is created equally; this is most prominent in magnesium levels. Some forms are cheaper and not nearly as effective. This is important in relation to B12; why? this is because about 40% of the population suffers from a deficiency due to genetic mutations found at MTHFR locus.

Basically, this means some forms get "caught up" during the metabolic process. So, they aren't readily available for use. In patients whose body has an excess level of methylation, it is beneficial to keep B12 in the body for longer periods of time so the tissues can fully utilize it. So, effectiveness will correlate to what's bound to the cobalamin infrastructure.

It is best to avoid cyanocobalamin shots when possible. Many weight loss clinics and physicians use this form in treating patients. Yes, the shots are still superior to the oral supplement, but you still aren't getting the full benefit with cyanocobalmin. In terms of symptomatic relief, methylcobalamin is going to deliver superior results. I note this in patients who've had B12 shots elsewhere. When I use my injection, they notice an immediate difference in their system.

FAQ: What you should know about B12

It's likely after reading this, questions will still pop up as it pertains to Vitamin B12. So, I've added this frequently asked question section to guide patients. I have treated hundreds of patients, and these are based upon my experiences. For those looking for a reliable and safe site to buy B12 shots, I've provided a reliable link below. You will receive 10 injections which include syringes and injection needles.

So, here are a few common questions patients have.

 1. Where can I get the right form of B12 shots?

To find high quality methylcobalamin shots, if you aren't looking in the right place, it can be a challenge. An integrative physician in your local area will typically supply them, but we recommend you talking to our staff at Nuimage Medical for finding our the correct dosing & form on b12 injection for your needs. Contact us today to speak with a licensed tele-medicine doctor to obtain your own Vitamin b12 supplements.

 2. Will the shots work for me?

It's not an exact science, but in my practice, 60-70% of patients benefit in some form or another. Higher energy levels and fewer crashes are the most common benefits my patients experience. If you've taken high quality B12 shots in the past, but haven't experienced any improvement, then they might not work for you.

I recommend the shots as a part of a comprehensive health plan. Using it in isolation isn't going to make a huge difference for most patients. Keep in mind that very little risk exists in using the shot; and, the benefits can be truly spectacular if they benefit you. So, it's worth at least a trial run if you are suffering from the above symptoms and want to experience relief.

 3. Where should injection occur?

The length of the needle, and whether you choose intramuscular or subcutaneous methods will dictate this answer. I prefer subcutaneous meaning smaller needles, and more injection points on the body. The abdomen, shoulder, thigh, and gluteal region are all viable locations. With intramuscular you are typically limited to areas like the shoulder area.

 4. Does intramuscular versus subcutaneous injection make a difference? 

With subcutaneous injection patients find it to be less painful as it doesn't go as deep into the tissues. Increased compliance is another benefit of subcutaneous injection and both have similar efficacy levels. Ultimately, the choice is up to you, and is based upon personal preference. But, in terms of benefits, there are no differences between which of the two injection methods you decide upon.

 5. How often should I inject?

I recommend 5000 mcg weekly, but in certain cases decreases occur with some patients. In some cases, using 3000 mcg, three time a week might be better tolerated, and help with increased energy levels in certain patients. I rely on labs, symptoms, and how the patient is reacting to treatment, to determine dosage over time.

 6. Is there such thing as Too Much B12?

As a water-soluble vitamin, this means B12 is safely eliminated by the body. It is filtered through the blood-stream and kidneys. High toxicity levels and vitaminosis typically occur.

Ready to buy your own B12 injections?

If you're ready to buy your own vile of Vitamin b12 injections, click here to contact one of our licensed tele-medicine physicans today and we will work with you 1 on 1 to reach your peak health & fitness goals today!

About the author

Dr. Constance Odom, MD

8 min read