Maximum daily amount of B12 one can take

Right before I was diagnosed with PD, my wife took me to Stanford Medical where two neurologists went over my symptoms and observed my body mobility and balance (or lack, thereof: had difficulty walking and body rigitity). They ended up giving me a Vitamin B 12 injection which greatly helped to improve most of my weaknesses. I had been a true vegan at the time, but began supplementing my diet with eggs and some dairy. With physical therapy and daily exercise routincs, I have regained/improved most of the physical obstacles caused by PD. I'm currently focusing on balance and strength, and although I've had to give up surfing (my lifelong love), my goal now is to get back out on the tennis courts. I have age and cognitive decline--working on keeping my mind as shart as possible, but I believe that it's not an insurmountacle goal. I'm now able to jog, walk for about 40 minutes/day, and went back to doing tai chi even though I haven't found a partner or group in my area to work out with. Fortunately, I've studied martial arts for more than fifty years, so I'm able to compare myself now to my younger self; tennis, I hope, will be the same.

I shared articles that you sent to me about B12 with my functional medicine doctor and asked for a blood test for B12. She is requesting a comprehensive blood test which includes homocysteine levels and said that homocysteine reflects B6 and B12 levels and is more reliable than a blood test for B12. I'll take the blood test she requested. We shall see.

I have been a vegetarian/vegan for 45 years and never knew - and was NEVER told about the relationship between B12 and neuropathy. My mother has bunions, hammer toes and i thought I had just inherited bad feet and suffered with it. I have researched myself and realized the significance of B12 and have nerve tests at podiatrists but no nutritional counseling. My feet are awful - i take a multivitamin, 2500 mcg B12 every day and B12 shots every other week. I’m a mess!

Hi @mariannelarsen, Welcome to Connect. It's great that you are doing your own research and learning as much as you can about your condition. I think all of us have been there in the I'm a mess state. What really helped me get out of it was finding Connect when I was first diagnosed with neuropathy and learning as much as I can about the condition and treatments that may provide some help or slow the progression. If you haven't already seen it, you might want to bookmark the following site and browse through the information and the videos on their webinars page here - https://www.foundationforpn.org/past-webinars/.

Which neuropathy symptom bothers you the most?

Thank you John - lll check it out. I don’t have pain but my toes feel
incredibly stiff and “thick”. I have not been able to wiggle them for
years! It’s mostly uncomfortable at night and I am unnerved by the
fluttering sensations In my legs
The embarrassing thing is that I am a nurse and should have researched this
before but I was a marathon runner and focused mainly on my weekly mileage
and staying away from any animal Ingredient foods. Plus I am a woman and
used to enduring pain!! Haha

In reading this, I se the original question was never answered. How much B12 is too much?
B12 can be given as an injection or taken orally. The injection is totally absorbed by the body. Some people have a problem with absorbing oral B12. If so, there is a preparation called methylated B12, which is absorbed.
The body uses all the B12 it needs, and excretes the rest in the urine. Some people get mild symptoms if taking too much, such as nausea. There are no serious effects of taking too much.
The important point is whether you need to take it. There is a simple blood test for B2 levels, and a described range of normal. If you are in the normal range, you do not need to take it, it will just be excreted.
If your B12 levels are low normal, especially if you are older, you may have to take other blood tests, as mentioned above, to demonstrate whether or not you really need B12 supplements.
Common B12 supplements have much. more B12 than you need. Most people do not need supplements, as they get enough B12 from their diet.

Thank you for the link to the webinars page. I'm interested in learning more about balance as I already feel that my balance has been compromised by PN. I'm doing exercises that I've learned from from my physical therapist. I looked at the webinar information on Balance and I'm interested in finding out more about Walkasins which is mentioned in one of the slides.

One thing to add: B12 shots alone may not do enough. I needed to take 5000mcg orally daily to get my levels up (the CVS chewable 5000mcg worked fine). One of my neurologists, Dr, Oaklander, said she wanted my levels to be 600-1000. They are now over 1,000 most of the time when I get tested.

BTW so far it's not helping anything and my foot neuropathy is still gradually getting worse.

You might want to read through this discussion. I'm not sure Walkasins are readily available yet.
--- Peripheral sensory neuropathy - Anyone tried Walkasins?: https://connect.mayoclinic.org/discussion/peripheral-sensory-neuropathy-device/

Here is a quote from an article I"ll reference. The whole article is easy to read and fairly non technical: "A serum vitamin B12 level between 200 pg/mL and 900 pg/mL is considered normal, but a threshold of 300 to 350 pg/mL is recognized as a marker for a desirable status in the elderly. The laboratory diagnosis is usually based on low serum vitamin B12 levels or elevated serum methylmalonic acid and homocysteine levels. Elevated homocysteine is an important marker for vitamin B12 and/or folate deficiency. Classic deficiency symptoms such as megaloblastic anemia often fail to appear with subtle deficiencies, as they are usually late clinical signs of severe deficiency.3,4 Symptoms of vitamin B12 deficiency include anemia, neuropathy, and neuropsychiatric disorders."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2781043/#:~:text=A%20serum%20vitamin%20B12,methylmalonic%20acid%20and%20homocysteine%20levels.
I would be interested in knowing why Dr. Oaklander wanted your B12 level to be higher than normal. You might ask her to direct you to references that support that idea. Your's is only one case (although it's certainly the most important case to you!), and doesn't prove anything, but notice that even at higher than normal levels, you have noted no improvement, and the disease progression continues. It is possible that B12 has nothing to do with your form of PN.
At this point in time, PN is an extraordinarily difficult and frustrating disease. Hopefully, that will change in the future. This situation affects everyone: patients, doctors, families, etc. Do the best you can, stay informed, and try to have a positive attitude.