Recently I've read some research related to this question.
@nanonug ,while there study above mentions interesting findings and concludes that some individuals metabolize DCA faster than others and thus doses should vary, there are some other examples of widely prescribed medications that also vary for each individual.
Take for example ACE inhibitors prescribed for people with chronic heart failure (about 6 million people have heart failure in USA and a large portion receives ACE inhibitors).
"As an example, up to
one third of patients with congestive heart failure may not tolerate or respond to
ACE inhibitor therapy [15,16]. In the late 1980s, researchers began investigating
genetic factors to determine the origins of inter-individual variability in patients' responses to
ACE inhibitor therapy."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1283147/
ACE inhibitors are still prescribed for patents in all over the world.
Regarding the dosing and safety for Dichloroacetate - there has been a large and long study on this.
"Another recently completed randomized, controlled trial investigated the same dichloroacetate dose in 43 young children (mean age at entry: 5.6 years) with congenital lactic acidosis (CLA) because of defects in pyruvate dehydrogenase or in ≥1 complex of the respiratory chain or a mitochondrial DNA mutation.
3 In contrast to the findings in older subjects with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes, this study demonstrated good tolerability of dichloroacetate, and there were no significant differences in the severity or frequency of adverse events between the drug and placebo groups after 6 months of treatment.
Here we report our experience with long-term administration of dichloroacetate in the 36 children on the trial who received dichloroacetate, from their starting times on the drug. Some of these patients have received treatment continuously for ~10 years."
So, young people received 12,5 mg/kg of DCA daily. Someone who weights 50 kg or 110 lbs took 625 mg of DCA daily for loooong periods of time (minimum of 2 years, some even 10 years).
Frank Comhaire suggests that a formula with 400 mg of DCA daily should be okay for people with ME/CFS in his study. As far as I get it, he decided to use a dose which is even below the minimal threshold for side effects to occur. 400 mg of DCA should be safe for most of the people, despite the fact if they have EGT (faster DCA metabolism) or they don't have EGT (slower DCA metabolism).
These are my thoughts, however, I could also be wrong.