You can get cramps from vitamin B12 if your magnesium and/or potassium levels are low.
Cramps from vitamin B12 if magnesium and/or potassium levels are low

Some years ago I found I would get cramps from vitamin B12 injections in the evening, past the time I exercised. If I did 5 minutes of exercise on my Gazelle after a B12 injection, then I had no cramping in my legs during the night.

Later I discovered that as long as I had a magnesium tablet before or shortly after an evening vitamin B12 injection, I did not get cramps.

Cramps despite the research

Cramps from vitamin B12 surprised me. When I had researched B12 the studies overwhelmingly said there was no danger of taking too much; therefore, vitamin B12 was harmless. But suddenly I was having cramps from vitamin B12. That didn’t seem harmless.

On the other hand, it was pretty simple to have a magnesium tablet when I had an evening B12 injection.

Sometime later I learned about Methylcobalamin lozenges, and happily used 5 or more 5 mg. lozenges a day. That was how much B12 I needed so that I wouldn’t have nose bleeds, feel depressed or have numb feet, among other signs of low vitamin B12 levels.

It was great to know that as long as I had a magnesium tablet I didn’t get cramps in my legs or feet from vitamin B12.

Jarrow Methyl B12, 5000mcg, 60 Lozenges

 Jarrow Methyl B12 5000 mcg


YIKES! Excruciating cramps from B12

Then I hurt my back. Each time the pain woke me during the night I used another 5 mg. Methylcobalamin lozenge. I believed it helped with the pain.

It may have helped at first but before long I was getting excruciating muscle spasms that affected not just all of each of my legs, but also my torso, which was scary.

I hated to think it was possible to take too much B12, still, I cut way back.

It was also around then that I learned vitamin B12 comes from micro-organisms and is plentiful in the air and soil.

I thought about how B12 (cobalamin) is characterized by its cobalt content. Perhaps, I thought, I have a build-up of the heavy metal cobalt.

So, I looked into what people use to get rid of heavy metals in the body. Turns out it’s cilantro.

I ordered two bottles of cilantro capsules on August 12, 2012 and took them religiously when they first arrived, and for several months thereafter. I also used Milk Thistle, with the thought that if the cilantro was clearing out the heavy metal, I didn’t want it all stuck in my liver.


Today, I’m almost completely fine, and am using more than one 5 mg Methylcobalamin on many days.

B12, Muscle Spasms, and Potassium

After reducing my vitamin B12 intake I began having peripheral neuoropathy pain again, keeping me awake much of the night. Admittedly it was after a lot of stress and I hadn’t been using additional Methylcobalamin. (In fact I was getting shingles).

After I tweeted about getting painful cramps from vitamin B12, someone tweeted back about excessively low potassium, known as Hypokalemia.

Apparently hypokalemia is reported by many people as a complication of vitamin B12 replacement after deficiency. This is because B12 normalizes blood cells so they once again grow and divide properly, which takes a lot of potassium and depletes circulating stores. The lack of adequate potassium causes cramps.

Graphic showing foods high in potassium - avocado, banana, potato, spinach, beans, citrus, fishThere’s a lot of potassium in bananas, potatoes, and other foods. But, if you’re not eating them or are eating processed varieties, supplements may seem like the answer. Except, after much looking-for-the-best I found 96 mg was about what I could expect from a potassium tablet or capsule. Whereas we need about 4,700 mg of potassium a day.

I learned that the bicarbonate form of potassium helps alkalize body pH. This is in marked contrast to a chloride form that is acidifying. Potassium in fruits and vegetables is the bicarbonate form. (More information on alkalizing vs acidifying.)

Potassium citrate is readily absorbed, improves calcium balance, and slows the crystallization of calcium-containing kidney stones. Potassium aspartate is already bound to aspartic acid which activates energy-rich phosphates. I’m ordering… Today! And I did, but I never opened them because by the time they arrived I’d learned about Maca and other foods containing potassium.

Jarrow Methyl B12, 5000mcg, 60 Lozenges

 Jarrow Methyl B12 5000 mcg