Before we get into methylcobalamin vs cyanocobalamin, let me just cover briefly why B12 is super important.
In a nutshell, it keeps your nerves and red blood cells healthy and takes responsibility for the smooth functioning of many critical body processes.
B12 also helps with digestion and heart health, so deficiency can lead to digestive disorders and an increased risk of heart disease.
The National Institute of Health’s (NIH) Dietary Office estimates that between 1.5–15 percent of U.S. citizens are B12 deficient.
The American Journal of Clinical Nutrition suggests this number might be up to 39 percent of the population suffering vitamin B12 deficiency.
In this post I explain exactly what B12 is and where it comes from. You can read that after this.
But the reality is that vegans and meat eaters could both do with more B12 and should supplement.
The way we live and the environment we live in has changed dramatically, and can lead any one of us towards a deficiency.
But which type of B12 should you take?
Let's get into this…
Methylcobalamin Vs Cyanocobalamin
Cyanocobalamin and Methylcobalamin are very similar. In fact, the only key chemical difference is a small part of the molecule. Methylcobalamin has a methyl group (just carbon and hydrogen), while cyanocobalamin has a cyanide group.
So, to help you remember, ‘cy' for cyanide is cyanocobalamin.
Cyanide isn’t something your body wants, as it's a poison.
But let's be clear: unless you are a smoker and your body just can't cope with any more cyanide, the amount of cyanide released in the conversion process of taking cyanocobalamin isn’t thought to be harmful enough to cause damage to your body.
What is true is that the body has no use for the cyano- compound itself, and will convert any cyanocobalamin you take into methylcobalamin anyway.
Most of the B12 circulating in the blood is in the methyl form. So if you take the cyano form, before it can be properly utilized by the body, it has to be stripped of its cyano group, which takes some time.
The primary reason cyanocobalamin is cheap is because it is synthesized in laboratories and is not harbored naturally in any living organism. It is cheaper to produce, basically.
Methyl B12 doesn't have to use any of the body's resources to convert it into the coenzyme form. You are essentially buying it pure, so to speak.
It is on this basis that pretty much every article you read on this subject will say to take methylcobalamin instead of cyanocobalamin.
But wait. It isn't that simple. Because when it comes to science we need to look at absorption rates to understand which form of B12 is better.
For example: You might be taking way more than the RDA for B12, but if your absorption rate is low, you still might not be getting enough. Some people absorb different forms of B12 better than others, which is why anyone can suffer from low B12, meat eater or vegan.
Which Form of B12 is Most Efficiently Absorbed?
There's a lot of debate regarding which form of B12 is better absorbed. Aside from hydroxocobalamin, which is usually administered by injection and best absorbed, of the oral types, a 1971 study found that at doses of 1 µg, 5 µg, and 25 µg, all forms were absorbed at about the same rate.
Note: µg = microgram, mg=milligram (1 milligram=1,000 micrograms)
However, the researchers suggested that at higher doses, cyanocobalamin is better absorbed.
They theorized that this could be because absorption of methylcobalamin by way of intrinsic factor is efficient, but cyanocobalamin is better absorbed through passive diffusion.
Intrinsic factor refers to a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B12.
Passive diffusion is the diffusion of small, uncharged, or hydrophobic molecules from an area of high concentration to an area of low concentration across the cell membrane.
Here's a table of the absorption rates:
At lower doses methylcobalamin does well, so if you take B12 daily this would be a good option. At much higher doses it is outperformed by cyanocobalamin, suggesting that if you take a weekly or monthly dose, this variety could be for yoy.
However, a 1973 study suggested that once absorbed, methylcobalamin may be retained in the body better than cyanocobalamin.
Regardless, researchers question whether the co-enzyme supplements are stable in their oral form and usually recommend doses above 1,000 µg/day.
More recent science seems to support this.
A 2011 clinical trial from Korea found that 1,500 µg/day of methylcobalamin was effective at increasing vitamin B12 levels.
This trial was conducted on those with vitamin B12 malabsorption, which suggests that for most people 1,500 µg/day would be more than enough. Unfortunately we don't have a comparison group for cyanocobalamin.
But Why is Methylcobalamin So Expensive?
While cyanocobalamin is cheap to produce, methylcobalamin isn't much more expensive and certainly doesn't warrant a price tag 10-15 times higher.
And since cyanocobalamin performs just as well in trials, it seems that the only real genuine benefit of methylcobalamin is the lack of cyanide in the former.
It's for this reason that the famous Dr. Gregor states:
B12 is so cheap to produce that supplement manufacturers try to come up with all sorts of fancy ways to “add value” to products so they can charge $30 a bottle. Unless you’re a smoker or have kidney failure, cyanocobalamin should be fine.
What is the Best Way to Take B12?
Most people are advised to take B12 sublingual, which means “under the tongue”.
Pills are sold for this purpose and dissolve under your tongue so it gets into your system quicker than going through the digestive tract.
The way to take a sublingual tablet is to just put the pill under your tongue and wait.
Careful though, as some sublinguals have more sugars in them that allow them to dissolve faster.
Sublingual B12 is much more expensive, and the evidence is mixed when it comes to absorption. This study found:
A dose of 500 micro g of cobalamin given either sublingually or orally is effective in correcting cobalamin deficiency.
In my own personal experience, sprays and drops are very effective and indeed my B12 levels are usually 600+ ng/L.
I'm very careful what I take though. And so should you be.
Some B-12 supplements, particularly sublingual tablets often contain sugar substitutes such as sorbitol, mannitol or sucralose, which can cause gastrointestinal symptoms in some people.
Both these brands I have used and come highly recommended. Both are organic and contain methylcobalamin. The GH variety contains a blend of methylcobalamin and adenosylcobalamin, considered highly bioactive forms of vitamin B-12.
Okay, we're done. I hope you swallowed all that – pardon the pun!
Now you know the difference between, and the truth about, methylcobalamin and cyanocobalamin.