Thanks for submitting your question. The reason that oral Dianabol is liver toxic is because it has to be processed by the liver before it can become active in the body. Since the injectable form bypasses the liver, it has a lower risk of liver toxicity and will not elevate your enzymes in the same way. However, this does not mean that the injections do NOT cause liver-related side effects. It can still impair hepatic function, even if it does not do it to the same degree as oral dosages. And yes, you are correct that high doses will increase the risk of adverse effects over low doses.
It shall be noticed, that in men, approximately 5% of testosterone undergoes 5α-reduction to form the more potent androgen, dihydrotestosterone (DHT), also known as androstanolone. From another side approximately % of testosterone is converted into estradiol (the primary female sex hormone) by aromatase an enzyme expressed in the brain, liver, and adipose tissues. Hence, don`t forget to take precautions to avoid respective side effects. Thereof we recommend to perform blood works and take aromatase inhibitors on cycle (if required, anastrozole preferably) and SERMs (clomifene, toremifene) during post cycle therapy (PCT).