Not that much really. Imo dbol is not that toxic. I've done liver tests basically on all orals I've done and dbol, for me, is a bit more toxic then var. This is from liver enzymes elevation. Dbol does lower my appetite more then var however. Anyway, I wouldn't worry about dbol's liver toxicity, especially at low dosages 10 - 20mg, I would be perfectly comfortable running that for 8 weeks. But mind you, your liver might react differently, so if you plan on running it for a longer period of time; do blood tests if you want to be safe. And use tudca and nac.