The structure is close to Methyl-Tren, the most toxic of all steroids, but it is unknown at this point. It is probably similar and maybe a little more liver toxic than M-1-T which is considered pretty toxic(Pat Arnold stated that mg for mg M-1-T was more potent than Tren, Anadrol and Dianabol and more toxic too).
Don't get me wrong, I'm not saying it is anywhere close to Methyl-Tren as far as toxicity goes, just that the structure is similar and it is an unknown at this point. Just something to keep in mind.