B12 500 mcg 1 a day keeps my level at top of range along with a B100. However, try it and get checked a month from now because people in Dr's office last week were talking B12 injections they take (didn't know dose) because they said their body doesn't have the ability to take it in orally.

Yes, this is low, but not really low... 400 is the cut off here and 500 in Japan. But you are borderline, and have a neuro disorder. That alone should qualify you for supplementation.

I'd do methylcobalamin 1000mcg a day on an empty stomach.
This is the active form, and does not need activation like cyano does.

This is my B12 thread that explains it:

http://neurotalk.psychcentral.com/thread85103.html

Doctors still remain clueless on oral, and active forms. So please do read up and take advantage of the low prices you can get on the best form, methylcobalamin.

I take 1000 per day...my B12 was really low...the old neuro thought it was causing my cog fog...nah...it's the MS. But I take it anyway.

I take 1000 B-12, like Mrs. D. does. I take 500 in the morning and 500 in the evening. Due to some lacking in my gut absorption.

Years ago it was so low I couldn't get off the couch, after giving birth. Never had that before, thought it was a relapse. I usually bounce right into normal activity.

I was tested, my B-12 was so low my GYN dr started giving me a B-12 shot weekly at his GYN office.

Funny after a few days I could feel it wearing off. I couldn't wait for the next hip/hinny shot. I had energy to spare. I don't know the dose, I was young and didn't even ask any questions about B-12 levels. I just believed in my doctor.

I was fine in no time at all, off shopping and out and about with three kids. Who knew?

I was told by that GYN to take oral 500 B-12 for the rest of my life. I took that amount until 2002, then I upped it to 1000 per MS doc. My blood work is 700-900 for B-12. I rather be high than low. I don't know how much my gut absorbs, but the blood is fine.

Now people give themselves B-12 shots. My last Neuro, in 2005, had his daughter give it to him. I laughed at him.

I said, you give other people MS meds to inject themselves, he had me on "C" at the time, and yet you are needle phobic to give them to yourself? He said, he can give them, but hates to do his own. Huh??

B12 has never been a problem with me; however, I thought a sublingual B12 was the best administration of it next to injections. Pills and tablets reduce dosage absorption down to 25 to 35 percent.

I can understand then why one would need a twice a day and 500mcg dosage taking that into consideration. My knowledge regarding B12 has diminished greatly over the years now.

They sell stuff that goes up your nose called EnerB. its a gel that goes up your nostril and absorbs thru the membrane in the nose.

You can also get shots. or increase B12 rich foods. The problem is that once we reach 30 most of us can no longer absorb B12 thru the gut. You can try allowing your pills to be crushed and then lay it under your tongue to absorb sublingually.

I hope you feel better.

Swallowing orally works. There are studies to show it works.

I don't think much is absorbed sublingually since the cobalamin molecule is so huge. It is dissolved in the saliva and swallowed.

What is important is to take on an empty stomach. Microgram quantities of any drug/supplement can be lost in stomach contents (esp fiber) and not be able to passively get thru the intestine. Now, this assumes you don't have intrinsic factor working properly and that is why you are low. Low or no intrinsic factor means the B12 has to cross the GI membranes passively and not hooked up to intrinsic factor. People with some or adequate intrinsic factor absorb more.

This link has pictures to explain it better:
http://www.aafp.org/afp/2003/0301/p979.html

Near the end of the paper is the data on oral forms working.

Remember, B12 is removed from the blood by transporters in the CNS. If the serum levels are low, then your spinal fluid becomes low, and there are studies showing MSers have low B12 in the CSF. The higher your serum reading, the better the transport into your CSF.

I think 1000mcg is best daily for average use. For people really low, 5000mcg daily is better. Methylcobalamin is best because many people lack the genetic capability to metabolize cyano (the synthetic form). This is called the MTHFR polymorphism failure and is quite common. Using the methyl form of B12 which is readily available now and inexpensive is the best way to go. Pennies a day... wish everything could be this affordable!