There are two basic types of Animal products, "foundational" and "cycled". Foundational Animal products like Pak, Flex, Juiced Aminos, Whey, Mass, Nitro, Omega or PM you can take daily.
Animal Stak is cycled. For products like Cuts, M-Stak, Test, and Stak, you "cycle" (21 days on, 7 days off). After three complete cycles, we suggest taking a month off before proceeding with another Stak cycle.
No, there is no need to do so. Our products increase your natural hormone production by means of natural ingredients, not by introducing outside hormones to the system. Therefore, there is no shutdown, rebound, etc.
Being the most potent product in the Animal line and being one most directly targeted for enhanced testosterone production, we feel Test should only be used by those 21 yrs of age or older. In your teens and developmental years supplement use should be limited, especially the use of testosterone specific formulas considering that endogenous hormone levels are at their peak during this period.