First off: 4 weeks is too short IMO (I've ran 4 RAD-140 cycles ranging from 10-30mg). I have found that 8-10 weeks is the optimal cycle length. 4 is too short, as it takes 10-16 days from what I have found in my research for the compound to fully kick in. 10+ weeks is too long as after 10 weeks the compound seems to have less of an effect and the greater the health risk. In terms of sides: the most noticeable and annoying I have found is insomnia. I have found it takes longer to fall asleep, and stay asleep on RAD-140. However, the small amount of sleep I have found is VERY deep and 6 hours feels like 12+. Second is irritability, if you have a short fuse, RAD will make it even shorter. Third, if you are prone to hair loss, RAD-140 will accelerate the process and you WILL have hair fall out. Now post cycle is a different story. Even with PCT you will be supressed. May feel a little depressed/anxious.
Happy lifting!