Max Berry has analyzed Minicircle's follistatin gene therapy, and I agree with his conclusion that it is unlikely to be effective. There are several aspects of their design that could be improved (in particular, using a more efficient lipid nanoparticle delivery system instead of PEI, and making a better choice of promoter). Overall, it seems like they are overcharging for a product of limited value.

I'm posting this here because there has recently been substantial discussion of Minicircle in the rationalist community.