As I've noted in previous posts, my integrative doc prescribed methylated b complex transdermal cream last month. After a few days of use, I had terrible side effects. After posting here, was told that because of ratios in the cream, I might be experiencing methyl trapping. I stopped the cream the last week of Oct. I feel much better but have had shortness of breath since. My Vitamin D levels showed to be low normal (45) in September. My potassium level was 4.4 last week. I have only found one older post by Fredd that mentioned methylation start-up can cause Vitamin D to tank. Have not been able to find that anywhere else I've searched online. I know it can cause potassium to fall. I've started supplementing with Vitamin D3 10,000iu's daily and there is a definite correlation. I'm also taking 1000mcg's of Hydroxy B12 daily. I know B12 deficiency can also cause shortness of breath even though my B12 levels showed to be normal (464). The tightness in my lungs has definitely eased but is still there. I want to add Dibencozide soon but am trying to get my breathing normalized before I do. Has anyone else heard of or experienced Vitamin D levels falling with methylation start-up? Too, do you think I would benefit from a little potassium supplementation?