Yes, there are, which honestly makes this entire article premise a bit bizarre. Double blind and all that is an ideal, not a requirement. It can't be a requirement, because whether we can run double-blind or any other kind of study is not always a matter of how good we are or how much effort we are willing to put in, but a characteristic of the thing we want to study, as it is here. It's hardly the only drug where the participants can have a pretty good guess whether they're on a placebo or not. As just an example off the top of my head, I doubt there were a whole lot of chemotherapy testers who thought they were vomiting for days and losing their hair due to a placebo.

Contrary to frequently-expressed opinion online, we are not in fact constrained to running only super-massive-sample-size triple-blind preregistered peer-reviewed gold-plated scientific studies and only permitted to say we might have an opinion if a metanalysis of multiple of those concurs. It's nice when we can do that, but the universe is not always so accommodating.