I used tren at 37.5mg/day on my first cycle. I was 200 lbs. 6'2" and around 17% BF at the start of the cycle. I was using it to bulk and hit 220lbs. in about five weeks. Oddly enough, even though I was eating everything in sight it appeared as though I lost a little BF along the way. Tren is ok for a first cycle if you have your diet and training down. The only difficult thing about doing tren for the first time is the daily injections. Some people have difficulty shooting every day for 6 weeks if they haven't experienced it before. As for side effects, I had bad migraines, insomnia, a little bit of increased blood pressure and I sweated like a pig.