Cyanocobalamin vs Methylcobalamin: Which Version is Best?

Cyanocobalamin vs Methylcobalamin: Which Version is Best?

B12 Deficiency is Very Common

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B12 deficiency is incredibly common among people of all age ranges. 

And despite the fact that we fortify B12 in just about every type of energy drink or “energy” supplement imaginable, B12 deficiency still rears its head. 

Why is that?

It has to do with how difficult it is for the body to absorb B12 in the intestinal tract. 

B12 absorption starts in the stomach with something called intrinsic factor (1) and eventually makes its way to the small intestine where it is fully absorbed. 

From there it must make it into the body and get activated by the right enzymes before your body can use it. 

But it turns out that this path is fraught with dangers that can and do impact vitamin B12 along the way. 

One of the most common causes of B12 deficiency is inflammation in the stomach. 

It’s estimated that a huge portion of the population (2) (up to 50%) suffer from subclinical gastritis (inflammation in the stomach) from a bacteria known as H. pylori. 

This low grade gastritis, found in up to 50% of people, is enough to slowly cause problems with B12 in your body. 

And because it’s subclinical, it’s not caught until you are much older, typically in your 60’s.

So even if you don’t have a gross deficiency of B12 throughout your life, you may feel the biochemical effects of subclinical B12 deficiency in energy production and how you feel. 

This is where B12 supplements step in:

You can use B12 supplements to help provide your body with the B12 that it needs with one caveat:

It only works if you used the RIGHT type of B12. 

With that in mind, let’s talk about the difference between the various version of B12 and whether or not they are created equal. 

What’s the Difference between Cyanocobalamin and Methylcobalamin

The difference between cyanocobalamin and methylcobalamin is actually very simple. 

Both of these products are considered B12 so they don’t differ in that aspect. 

Where they differ is in what is attached to the B12. 

You can think of this as a carrier product that simply holds onto the B12 portion. 

These attachments/carriers help do a number of important things:

Stabilize the active component (in this case B12). Potentially alter when it is absorbed and in what part of the gut. Alter how difficult it is for the body to assimilate or use it. And lastly, they can provide the body with necessary or unnecessary substrate when the carrier product is cleaved from the B12 by the body. 

This is where things get interesting:

In the case of cyanocobalamin, B12 is attached to cyanide. 

You know, the same chemical compound that can be potentially fatal in large doses to humans. 

In the case of methylcobalamin, B12 is attached to a methyl group. 

Both of these attachments are really just variations of carbon and hydrogen atoms but the difference between the two is important. 

Most formulations of B12 come in the cyanocobalamin form simply because it’s cheaper to produce and manufacture. 

But there’s one big problem:

Those who take cyanocobalamin typically don’t feel any better, even while using large doses of B12. 

Furthermore, cyanocobalamin is not a form of B12 which is naturally found in nature. 

Cyanocobalamin is a human creation that does the job of getting the B12 into the body but may not do the best job at allowing the body to utilize it. 

That’s where methylcobalamin steps in. 

Methylcobalamin is attached to a methyl group and your body is very accustomed to using methylation intracellularly. 

Methylcobalamin also comes pre-activated compared to the cyanocobalamin version. 

There are many steps involved in processing B12 before your body can use it and one of those steps is the methylation process. 

One enzyme, in particular, plays an important role in this process, and it’s known as MTHFR or methylenetetrahydrofolate reductase (3). 

The methylated version of B12 can bypass some of the processing required by the body in order for utilization. 

Put simply:

Taking methylcobalamin allows the body to more easily use the B12 you are consuming. 

You can compare this to cyanocobalamin which requires extra steps to be used by the body assuming it actually makes it into the body through the gut. 

How does Hydroxycobalamin Compare?

We’ve talked about both cyanocobalamin and methylcobalamin but there are other forms of B12 that you should know about. 

One such version is known as hydroxycobalamin and this form of B12 occurs in nature much like methylcobalamin. 

Hydroxycobalamin is another pre-activated form of B12 found in animal protein such as beef (4). 

In fact, animal protein contains a number of pre-activated B12 versions including methylcobalamin, hydroxycobalamin, and adenosylcobalamin. 

You can compare this to cyanocobalamin which does not naturally occur in nature. 

It should tell you something when the primary version of B12 found in most over the counter supplements does not occur in nature (cyanocobalamin). 

The version of B12 that our body does BEST with includes those versions which are pre-activated, pre-methylated, and ready for utilization of the body. 

Hydroxycobalamin, much like methylcobalamin, is another variant of B12 which can be easily used by the body. 

When in doubt, opt for either a hydroxycobalamin or methylcobalamin supplement for this reason. 

Is Cyanocobalamin Harmful?

I mentioned it briefly above but I want to dive into a little more detail here. 

Because cyanocobalamin contains cyanide there are many people who are worried about potential issues with toxicity when consuming this form of B12. 

But is it really an issue?

It turns out that it probably isn’t. 

Your body is an all-star at detoxification and cleaving apart proteins for elimination and it does this quite well with cyanide found in cyanocobalamin. 

Even though it’s unlikely to cause serious toxicity or injury, you have to ask yourself if it’s worth it to put this form of B12 into your body knowing that it must be eliminated and detoxified out. 

My personal thought is that it is always preferable to use naturally occurring sources of vitamins/nutrients whenever possible and to avoid man-made synthetic versions. 

B12 Injections vs Sublingual B12 vs Oral B12

Hopefully, by now you have realized the importance of the different types of B12 available and how these forms impact the utilization of B12. 

The next thing we need to discuss is how you get that B12 into your body. 

It’s well known that B12 absorption can be somewhat fickle so attempts have been made to try and bypass the gut while still getting it into your body. 

There are 3 main ways that you can get B12 into your body:

  • Oral supplements taken and swallowed by the mouth that then go into your gut to get absorbed
  • Sublingual supplements that supposedly get absorbed under the tongue which then bypass the gut
  • And intramuscular or subcutaneous injections that bypass the gut entirely by being injected straight into the muscle

At first glance, it seems that the sublingual option is probably the best. 

But I’m not convinced that B12 is readily absorbed via the sublingual route

Studies (5) do show that sublingual B12 supplements do raise serum B12 levels but my personal experience suggests that sublingual supplements are probably not absorbed very well under the tongue. 

It’s more difficult than you think for certain products to get absorbed under the tongue. 

Some compounds take longer than others, some compounds require carriers to get across the membrane, and some compounds are too big to make it. 

Even though B12 is small enough to cross the membrane, I’m not convinced that most of it gets through the tissue under the tongue before it is washed away by saliva and taken down your throat into the gut. 

I’ve seen a number of people who take sublingual versions of B12 who do not feel any better until they start taking B12 injections

This suggests to me that the absorption under the tongue is not as good as most people think. 

On the other hand, it’s not necessarily ideal or practical to stick a needle in your arm once a week or more frequently to get your dose of B12. 

So what should you do?

One thing you can do to overcome absorption issues in the gut is to mega dose your B12. 

It turns out that you can brute force B12 absorption in the gut by bypassing the need for intrinsic factor when using large doses. 

Physiologically, a small percentage of B12 can make it across your intestinal tract without intrinsic factor. 

You can take advantage of this absorption method by simply increasing the dose of B12 that you take. 

But note that this only solves the absorption issue, it doesn’t solve the activation issue once it makes it into your body. 

You can megadose cyanocobalamin but it probably won’t have much impact on your body if you have issues with the activation process. 

It’s far better to megadose with B12 versions such as methylcobalamin, hydroxycobalamin, or adenosylcobalamin. 

How much Methylcobalamin or Hydroxycobalamin Should you Take?

How much you take really depends on you, the level of B12 in your body, how well your body absorbs that B12, and whether or not you have issues with activating that B12 once it is absorbed. 

That’s probably not what you want to hear, but it is the case!

What this means for you is that it will take some element of trial and error to really figure out how much B12 you should be taking. 

I can give you some additional guidelines to go on, though. 

The first is that you really shouldn’t be afraid to take a lot of B12. 

B12 is a water soluble vitamin which means that the risk of overdose is virtually zero. 

Any extra B12 that you consume will be eliminated by your kidneys and in your urine. 

Second, the RDA for things like B12 really doesn’t take into account the issues that we have mentioned here so don’t be afraid to take doses that are several times higher than the RDA. 

Third, there is a big difference between biochemical B12 deficiency and B12 deficiency symptoms. 

Many people walking around, including you, probably do not have gross symptoms of B12 deficiency but if we probed your blood for certain biochemical markers you would probably show signs of B12 deficiency. 

Fourth, standard lab tests such as the serum B12 are poor indicators of intracellular B12 levels

Whenever you take a B12 supplement you will see your serum B12 level skyrocket. 

This can freak out doctors who proclaim that you are “overdosing on B12!” when the reality is that your serum levels can be high but your cells may still be deficient. 

Furthermore, with functioning kidneys, the risk of overdose is basically zero. 

So what should you do?

I would start out with a B12 supplement that contains either methylcobalamin, hydroxycobalamin, or adenosylcobalamin and experiment with 1-4 capsules per day. 

Spread those capsules up throughout the day (don’t take them all at once) and over the course of the next 2-3 months monitor how you are feeling. 

Your body will tell you if you are on the right track. 

If this fails, don’t be afraid to try swapping around between various types of B12 routes. 

You may find that switching to B12 injections or to sublingual B12 may be better for your body compared to oral supplements. 

Final Thoughts

B12 deficiency is incredibly common and even though many people supplement with B12 they may not be getting the beneficial effects due to problems with absorption and utilization by the body. 

Whenever possible, avoid B12 supplements that contain cyanocobalamin and opt for supplements that contain methylcobalamin. 

Methylcobalamin comes pre-activated and is much easier for the body to use and process. 

In addition, methylcobalamin is a form of B12 found in nature which makes it ideal compared to cyanocobalamin. 

Now I want to hear from you:

Do you know or suspect that you have B12 deficiency?

Are you currently taking B12 supplements?

If so, what type of B12 are you using?

Have you had success using sublingual B12 or B12 shots?

Leave your questions or comments below! 






which is the safest form of B12?

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.

20 thoughts on “Cyanocobalamin vs Methylcobalamin: Which Version is Best?”

  1. Thank you so much for your thoroughness, I take a multi and a b complex. I do feel as though I’m not absorbing. What brand do you recommend? I do have MTHFR methylation errors.

  2. Hi,
    I just read your article on B12 and want to try to ease my symptoms (anxiety). As i live in France, I did not found Methylcobalamin in injection but only Hydroxocobalamin (10mg per injection). Is the dosage safe? Or should I ask for putting only half of the injection (just 5mg). Don’t want to overdose… Thanks in advance for your response,

  3. This was so helpful. Easy to understand and user friendly.
    Many thanks for posting this.
    B12 Deficient mama that was over whelmed on what one to purchase.

  4. Hi Dr. Childs,

    Thanks for this article! It’s proof that I should continue to listen to my body. I’ve been “allegedly” overdosing on my sublingual B12s consuming 10k a day. I feel amazing (focused, energized, flat tummy, good mental health, etc.)! When I share my “secrets”, others are afraid to do it. So I will be sharing this article with my friends.

    Can you talk about the third form of healthy B12 (adenosylcobalamin)? Interested to know more as some vitamins are now pushing to have all three beneficial components (M.H & A— made the types an acronym lol).

    Your diligence is saving lives,

    • Hi LaSheik,

      I will add it to the list of future topics to discuss! As a primer, adenosylcobalamin is another approved and safe form of B12 to use.

  5. For years my b12 has bottomed out and periodically I’ve been given the injections and also take the supplements and sublinguals. I still struggle. When I take b12 in any for it puts me to bed and I can sleep around the clock. When I do get up I’m not up for long and back in bed from absolute exhaustion. Taking b12 makes me more tired, I have greater shortness of breath, cognitive issues, etc… Any thoughts?

    • Hi Nancy,

      I’ve only ever really seen that one other time and I wasn’t ever really 100% confident why it occurred. My best guess had something to do with methylation pathways.

  6. Hi Dr Child’s …My name is Demi…need your input on this… it seems crazy after me coming on the web looking for help …. I’ve been using sublingual vitamin B 12 supplement 5000 mg under my tongue for years…one a day for YEARS NOT KNOWING … that it has cyanocobalamin in it …. Never once I have a problem I do take other vitamins..I take a D3 under my tongue that’s 5000 mg of sublingual… collagen powder, Bition for skin hair and nails… zinc…
    Omega threes, Ect…

    The reason why I’m coming to you is because my B12 sublingual under the tongue vitamin I had two huge bottles and it would last me over the year I finally just ran out, so I said I have to go get some more ,,,

    I go to the health store quite often …so I end up buying a vitamin B 12 5000 mg .quick dissolve chewable tablets but I decided to put it under my tongue for whatever reason I don’t know maybe because that’s what I’m used to …..but the ingredient is the one that you’re talking about that’s better for you for nature wise “Methylcobalamin” which my body is used to the other one …and I just started using it a few days ago and I’m confused because ever since I started using this new ingredient which is supposedly better for you a few days ago, I’ve just started getting a little feeling sensation like if I have to urinate more… knowing I just went to the bathroom and when I feel it I go and I still end up going to the bathroom it’s just a little sensation and it almost feels like it’s like warm and heated and tiny tiny very very little little prickly on my lower stomach….

    So wondering even though this brand is better, and my body is used to the other one do you think that has anything to do with it because that’s the only thing that changed a few days ago was the B12 and it caught my attention so I looked at the one I’m used to taking for many years is different ingredient and I googled it and this is what came up is your page….

    Sorry for the long conversation …I’m just curious even though Methylcobalamin is better for you ….do you think maybe my body is not used to taking it …cause I’m used to taking Cyanocobalamin.? .that it is bothering me it’s just confusing and I wonder if you have any input on that

    • Hi Demi,

      I’m unaware of a connection between your symptoms and methylcobalamin so I would lean towards the idea that they are an unrelated phenomenon. Before blaming the new supplement, I would look for other causes.

  7. I question your qualification – spreading FUD is apparent with the implication that the cyan attachment “may” be dangerous. So is chlorine but attachment to sodium in common salt does not raise the sort of ethical considerations you are promoting. Shame on you.

    B12 is the most complex of the Vitamin complex and so many varieties of B12 abound in nature, but it is not required for use in the plant kingdom.

    As far as I know this is the only part of our diet where the central Cobalt is required. According to Wikipedia the hydroxy type of B12 is used to counteract cyanide poisoning converting to the cyan form to be further used in the human system.

    The artificial cyanocobalamin is human ingenuity finding a way to give the vitamin long shelf life, and is cost effective.

    I accuse this of being a variation of the old fashioned “snake oil merchant” in order to promulgate his particular brand of “snake oil”

    • Hi WhiteDragon,

      You are certainly welcome to whatever opinion you’d like, that’s the beauty of life. Regarding using cyanocobalamin over methylcobalamin (or any other), please proceed with whatever you feel most comfortable with. In my own opinion, and when my health is on the line, I will choose options that do not contain a potentially harmful metabolite from the breakdown of said product. If you’d like to put that into your body, you are certainly welcome to. This article is for those who try to minimize the metabolism of unnecessary compounds in their body to obtain a healthier life.

  8. Hey Dr. Childs I appreciate your article, thank you. When I take a large dose of methylB12, I get severe insomnia that night. Even if I took it early in the morning. I’m young and healthy, good kidneys. I suspect methylation pathways are weird.

    I also wanted to ask you why I often find methylB12 supplements with added methylfolate. What is the methylfolate supposed to do? I have taken this and experienced insomnia.

    • Hi Alliene,

      Methylfolate is just a premethylated form of folate/folic acid. It’s required for cellular health and often added to B12 supplements.

  9. Hi Dr. Childs, I just sent a lengthy email to the “hello” email address, but likely you will never get that 🙂

    In a nutshell, are there medical reasons to pursue the WHY/root cause of the deficiency and not only just supplement for life? I had a B12 level of 161, with significant neuro symptoms, now getting monthly shots and doing daily sublingual supplement of 5000.
    -are there medical implications for me to know (for example: should I be cautious with anesthesia with nitrous oxide; are there future medical issues to be aware of (lack of intrinsic factor can be at risk for stomach cancer), are there endocrine issues that could be related, can this deficiency make you more sensitive to alcohol consumption?
    – -are there reasons for family members to be aware of for themselves and for their children?
    — are my children at risk for this? Do I need to make their pediatrician aware?
    –are there any specialists who might be more knowledgeable about this condition that I should be referred to?
    –is family history of Pernicious Anemia enough to assume that this is likely genetic (even though I technically “am not anemic”)
    –any correlation with type 2 diabetes?
    –could it be related to a gene issue like MTHFR?

    Needing to know what to do BESIDES just to supplement or at least what type of provider would be the best person to get referred to (endocrine, hematology, integrative medicine, GI?) to explore causes. Or if I am being supplemented adequately, is there any reason to worry about those things?

    • Hi Tricia,

      You could definitely be worked up for the cause of vitamin B12 deficiency. There are algorithms for identifying the cause of B12 deficiency that all medical students are taught. They just get tossed to the wayside once doctors start practicing because they are so uncommon and over-the-counter B12 supplements are a quick and easy solution for most issues. If you wanted to explore the potential causes then you’d just need to bring this up with your doctor and undergo the necessary tests. In terms of statistical probability, you’d want to look at your stomach for something like atrophic gastritis.

  10. I just started taking a 5 mg B12 sublingual methylcobalamin tablet. You mention that you are not convinced that the B12 is absorbed sublingually. Since after the tablet is dissolved, you end up swallowing the remains of the tablet, wouldn’t the remaining amount then be absorbed by the stomach? In other words, would whatever was not absorbed sublingually, then be absorbed gastrointestinally? Seems like this would cover both avenues. Please explain.

    • Hi Lisa,

      Yes, that is correct. The idea behind using sublingual B12 is that it bypasses the intestinal tract and I’m suggesting that the majority of it does NOT. Therefore, the benefit of using it sublingually is minimized and the absorption of sublingual B12 is likely comparable to B12 capsules both of which are inferior to B12 shots.


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