At least in rats. The rats were given 10 mg/kg Sustanon a week. That would be the equivalent of 800 mg a week for an average sized man. After 8 weeks of administration liver enzymes were measured and no significant changes seen. The abstract says:
Previous studies have shown that resistance training (RT) is the main exercise modality practiced by AAS abusers. Thus, this work was carried out to evaluate the hepatotoxic effects of sustanon (Su) as an example of AAS in trained male rats. Rats were divided into sedentary/non-Su, sedentary/Su, RT/non-Su, and RT/Su. Su-administration groups received Su 10 mg/kg intramuscularly once a week for 8 weeks. In the 8-week RT, the rats climbed a vertical ladder 3 days/week. After Su administration, the mean values of serum parameters related to hepatic function were within normal ranges.