People with no intrinsic factor do indeed absorb orally...
this is done PASSIVELY with large doses of 1 to 5 mg a day.

There are many studies to show this now works orally when taken daily on an empty stomach.

I would get the DNA testing for MTHFR mutations which are very common also to see if you require methylcobalamin. Most injections are cyano type and have to be methylated to work in the body. Otherwise you don't get the benefit of cyano injection or oral.
It will show up floating in your blood tests, but it will not work in tissues if you have the mutation.

Vitamin B12 Deficiency - American Family Physician

This link is for doctors education, but lay people can understand it too as it is written very well.

You can choose to do what you want. But do research showing oral will work, to save you the invasiveness of injections, and the use of the right type of B12 so it will actually work once injected.

I am sorry your doctor remains uninformed, but you can give him that article to explain the newer aspects of B12 therapy.

Thanks, mrsD. If I give this to my doctor, he will kick me out of his office, and I will have to spend another six months finding a new doctor and obtaining an appointment. That's just the way it is in my city. Maybe I can figure something else out.

I was wondering about my test results. Is there any way to know if the high test result is due to the oral B12 that I am taking in addition to the injections? Is 1718 an unremarkable result after only six weeks?

Injections remain in the blood for about 72 hrs. So you should be
tested at least 72 hrs after a shot. It is also necessary to
Stop oral B12 for about a week before testing. This will
give a more accurate result and less of a false elevation in
results.

Any doctor who would throw you out is not worth seeing.

With regard to the 1781 test, I set that up so that I had no oral vitamins, including B12, for three full days prior to the test, and no injection for two weeks prior to the test. I'll follow your parameters next time.

[EDIT: I apologize for going on in this thread. I'll try to stay on topic. :) ]

Recently, I tested POSITIVE (HETEROZYGOUS) for MTHFR C677T.

My endocrinologist wants me to take methylated B12 orally. He suggested Metanx and/or something else (I don't remember the name). I told him about the Jarrow B12 product, and he said okay to that. He is also keeping me on the B12 injections for the moment — just out of caution because I have the double whammy of no intrinsic factor and the genetic mutation.

I've had a very tired day today, but I have felt not so bad in the last few weeks.

Question: In addition to my rapidly receding hairline, the consistency of my hair is becoming like straw. Is this normal?

Thanks. :)

Latest Test:
B12
2000 pg/mL (213-816 pg/mL)

Following mrsD's advice, I abstained from all oral vitamins (including B vitamins) for 6 days prior to the test, and I had no injections of B12 for more than two weeks prior to the test.

I'd welcome anyone's thoughts on this result. :)

When I used 5mg orally every day for 3 months my test was 1999.

Several members here have had results that high when supplementing.

This test shows only the B12 in the serum and not the tissues.
There is B12 in red blood cells too, so if the sample ruptured the cells in the blood that would dump B12 into the serum and be a false (factititious) reading. This happens with potassium tests commonly. Using a butterfly thin needle to draw blood, or too tight a tourniquet can rupture the red cells.

A high reading (and 2000 is often the upper limit of the testing equipment), is not something to worry about generally. If you continue with symptoms over time however, with a high reading, then it would suggest you look for a reason. Adjusting your dosing is the first thing to adjust.

The testing does not discriminate between methyl or hydroxyl forms of B12 and cyano. The test measures the red color of the solution extracted from the serum, and not individual chemical analogues of B12. It is called a colorimetric test.

High dose folate not recommended for seniors:
 

This is a very important NEW article on research revealing
high dose folate consumed by seniors who have a specific mutation ( one in 6 so far) may lead to nerve damage
caused by blocked B12 within cells.

Thanks to Marlene for finding this new article:

https://www.sciencedaily.com/release...1012141654.htm

The bottom line is not to go over 800mcg/day.

My multi-vitamin has 1000 mcg of Folic Acid, and I have been taking 400 mcg of Methyl Folate. Too much?

I Positive (HETEROZYGOUS) for MTHFR C677T.

I'd find another multivitamin.
Most only have 400mcg folic acid.

This is a new finding, so I don't know the long term effects about this situation. The mutation in the article on the link,
is not the same as the MTHFR one. Look thru your test results and see if you have the specific mutation mentioned there and/or discuss with your doctor.