Hi, No "expert" here, but I'd suggest reading up about B12 levels and getting yours raised a lot more. There's an absolutely incredible source of information about B12 and other vitamins in the Vitamins forum here at NT and also at the top of the PN forum (esp B12).

I use the forum search feature and type in name of vitamin or hormone I'm looking for and add username for the person's information I want. I use either - mrsD or glenntaj. That'll bring up threads or posts that I know will be helpful.

e.g. https://www.neurotalk.org/1282714-post9.html

Might be hard to read if you've got a bit of brain fog or screen strain like me but using the forum search like that tends to sort out the posts a lot for me that's for sure. You should try that for the Niacin too.

What's your calcium level that you're not fussed about? Calcium is in a loop with Vit D and Parathyroid Hormone. Worth checking into that too depending on how low it.

I don't know how long you've been taking 2000 mg D3 but if you've been taking it a long time and your calcium is low then you should talk with your doctor about that.

The CRP is C-reactive protein measuring inflammation or infection.

If you are testing B12 and are taking supplementation then cease it for about a week before the test.

Always talk with your doctor before adding anything into the mix.