UDCA/TUDCA has nothing to do with PCT- it is there to protect liver and prevent or slow down damage done to liver from methylated steroids, medications etc... So whenever you use anything that is bad for liver these things should be usedalon few other bits. They can be used all year round, no problem. I always suggest people to use it during cycle and beggining of PCT- and then use "essentiale forte" which basically helps regenerate liver.