There is no actual "protection". In fact, I have not seen much, if any difference using liver aids while on cycle. The only real answer is time off of compounds that will damage the liver, to allow it to heal. Still, I use 1000mg milk thistle and at times, liv-52, as well as NAC. It sounds like you are doing what you can do, limiting the time frame for oral useage. Continue on that plan, and you will be much safer than someone who uses orals through out a cycle. Do keep in mind that injectables do tax the liver, just not as dramatically as orals, so time off from them is essential for total recovery. Your best bet is to get labs done, so you can check (along with other tests) your liver function, every 3-4 months. Liver values will be higher on cycle, but they will return when you come off