I was reading a monograph of vitamin B5 or pantothenic acid. You can read it here. Among the many symptoms caused by a mild deficiency, orthostatic hypotention was one of them. B5 is needed to make acetyl coa. Acetyl coa together with choline make acetylcholine (Ach). This is the main neurotransmitter in the autonomic nervous system. Low Ach levels lead to hypotonia, hypotension, weakness, etc. Mestinon works by increasing levels of Ach so you get the idea. B5 is found is most b complex s