loveofdogs, investigate sublingual Fast Melt Methylcobalamin. It gets in the blood stream quickly. Don't overlook thiamine. Magnesium is needed to activate it and vitamin D. Are you getting enough magnesium? Activated thiamine in turn activates B6. The B vitamins wotk better together. A form of thiamine, benfotiamine, offers advantages you may need to benefit from and can be used together with a B Complex. However, anti thiamine factors can diminish or destroy thiamine as listed in the stuttersence link. The critical part to also check out is the role activated thiamine has in the brain, vagus nerve and gut. Always consult your health care professional before using any supplement.
https://sperlingmedicalgroup.com/lack-of-vitamin-b12-can-cause-tremor-symptoms/#:~:text=However%2C%20tremors%20and%20other%20movement,occur%20even%20in%20mild%20deficiency.
https://www.healthline.com/nutrition/methylcobalamin-vs-cyanocobalamin
http://stuttersense.blogspot.com/2014/08/these-factors-reduce-your-thiamine.html