^^I was surprised when you said that R-lipoic might affect Biotin levels. I guess I had a false sense of the "safety" of R-lipoic.

One really has to keep track of the big picture, i addition to looking into individual supplements.

Thanks, mrsD!

There is no real proof yet of this interaction. However, it is suggested by animal studies so far.

None of the lipoic acid sites I visited mention it either. But the biotin sites do occasionally.

That WebMD monograph does not mention the lipoic acid either.
And it does not mention the biotin on its alpha lipoic acid monograph. So it is not easy to find this interaction.

It is not a false sense of safety exactly.... since lipoic acid doesn't show toxicity itself. What is thought to happen is that the transporter system that moves it around is shared by lipoic acid, and B5, along with the biotin. What it is however, is that
one of the 3 that use that transporter gets blocked and therefore becomes ineffective because it can't do its job.

Normally our bodies make lipoic acid in small amounts all the time. It is when large amounts of any of the 3 or all of them are taken in supplement form, that the transporter system gets overloaded.
And keep in mind it is early days so far with this new discovery. That is why it is difficult to find information on.