Let's look at this from both angles and arguments that are presented here... There are valid reasons for both sets of thoughts but there is a BETTER and WISER option between the two...
CAN YOU run tren on a second cycle... Of course you can... Why can't you? You have already introduced your body to a foreign substance in a previous cycle so you have "some sort" of idea on how it reacts to anabolics... You have already had some experiences and your body has adjusted to these situations... You can also run the acetate ester allowing yourself to stop quickly if your body does not respond favorably... No harm, no foul and if you are lucky enough to not have intolerable sides, you can run it and make drastic gains...
Let's look at it from the other perspective... Your only 25... You've only ran ONE real cycle... You are opting for one of the harshest steroids you can use as well as one of the strongest... Where do you go from there after you run it? Are you planning on running tren every cycle from here on out? Don't you have a lot of other options to run as opposed to tren that will have much less side effects and still provide excellent results? I just made a new video called "Steroids: A marathon, not a sprint" Check it out...
Steroid Use: A Marathon, Not A Sprint: By Dylan Gemelli - YouTube When you run something like primo for example, you are getting amazing gains, with minimal side effects and you can run it over and over without having to worry about the long term damage that continuous tren use could give... You don't need tren right now... Are you going pro? If you are, then of course, go with tren... I don't believe that's your circumstance though... Why run it now? There's no need when you have so many other options to explore... Run it later... Build up more toward it... Run it when you really need it for something and get the most bang out of it as it will be your first time running it... Explore other options first... Its a marathon, not a sprint... Take your time and be aggressive while still being conservative...
You can run it on a second cycle, yes, but is it the wisest option... For me, no, it's not... Stick with primo on this one... You will be very happy that you did...