I now take the R-ALA that is included in the Protocol (https://theprotocolworks.com/). Before it was developed by the Facebook group mentioned on their website we used to maintain a list of each of the supplements and ordered them online. I have used several different R-ALA supplements in the past, here's a few:
-- Life Extension 240mg: https://www.amazon.com/gp/aw/d/B0027YKO1C/
-- Premium Supplements 300mg: https://www.amazon.com/R-Alpha-Lipoic-R-LIPOIC-count-STRENGTH/dp/B01M0QS5C7