If you have POTS, are not currently taking LDN, and can make it to the University of Calgary for two visits, this trial may be of interest:
https://research.ucalgary.ca/participate/low-dose-naltrexone-ldn-use-pots-reb22-0565
https://research.ucalgary.ca/participate/low-dose-naltrexone-ldn-use-pots-reb22-0565