Right after Hinault retired from was on La Vie Claire, I was lucky enough to follow the team around for a few stages in 1987. Hinault was around and was not hesitant at all to talk story. He said that there were homeopathic and 'other' things that were extremely effective, and not on any prohibited list. Considering what the 'list' looked like in 1987 it is not hard to believe that he may have been taking products that were legal at the time, but would be prohibited today.
Other noteworthy point: The team staff included Paul Koechli and Claude Genzling who collaborated with Hinault 2.0 on a total repositioning on the bike, and who were also quite outspoken on the non-use of drugs.
La Vie Claire was, ironically, a nutritional company advocating the "Clear Life" and was owned by Bernard Tapie, who was famous for going to jail after convicted for match fixing in soccer. He also owned the Marseille soccer team, and briefly, adidas.
Was Hinault clean? Probably. Probably the best all-round GT rider of the era, pre Lemond.