Methyl B12 injections and Diabetes

Question: 

My 12 year old cat is diabetic and is currently on a twice a day insulin dosage. For the past several months he has been experiencing problems walking (walking on the hocks of his back legs, condition neuropathy) which is common if the blood glucose levels are not regulated. I read on the internet that some diabetic cats with neuropathy have shown improvement within a couple of weeks with Methyl B12 injections. I asked my vet about this and they gave me regular B12 injections to administer. I understand that the B12 I have is not the correct B12 form that has been shown to improve neuropathy symptoms in cats.

Could you please provide some insight on if methyl B12 exists and give me the information I need to provide my vet in order to give the best possible chance to my cat to regain his walking ability fully. We are still working on getting his blood glucose levels fully regulated (regular blood glucose curve checks, fructosomine checks, etc). I know the condition could possibly improve on its own once blood glucose levels are regulated but I would love to try the methyl B12 injections in addition too. Thanks for your time and look forward to hearing your suggestions.

Answer: 

Thank you for your question. It is unfortunate that your cat is having complications from diabetes. You are correct that B12 (i.e. cyanocobalamine) is different from methyl-B12 (i.e. methylcobalamine). The use of methyl-B12 is not something that is routinely done in cats, however it is unlikely that it would be harmful.  The literature available does indicate that this specific form of B12 can improve neuronal firing (at least in rats and in some human studies), however no controlled studies have been performed in cats to our knowledge. From reviewing the literature available, it appears that the methyl-B12 actually has a more protective affect against the development of peripheral neuropathies (i.e. it is best given before the signs of a plantegrade stance are seen) rather than causing it to be reversed. 

That being said, B12 is a water soluble vitamin and should be safe, therefore reasonable to try. The down side is there is no dosing available in cats published in a scientific source. There is a veterinary formulation called Zobaline that is specifically made for cats with diabetes. The recommend dose (from the manufacturer, not a veterinarain) is 3 mg per cat per day orally.