DMT (when vapored) is not working as a preventative, only as an abortive. Its what imigran / imitrex injections are made of. I can not speak of the ayahuasca experience, altough that seems far more dangerous having that MAOI included in the mix.
the product described there is a research chemical. It is not tested for human consumption. Therefore i would not recommend this for medicinal usage. Long term effects are not known, and most of the times those "RC's" as people call them, go out of stock pretty quickly because it eventually becomes illegal.