Hi, I have been taking small amounts of Thiamine for about 10 days now and I noticed from the first day that I slept better. I can only take about 25 mg though because anything more will give me a headache. But when I take that 25mg at night it will help me sleep better and I feel less agitation the next day... However, I have not seen much difference in slowing down my speeding heart rate.. It's still around 90 while sitting and 110 when standing after 10 min. But now that I can see some improvements with Thiamine I would love some education on what pathways does it effect to help people with POTS with sleep and calmness?