Definitely so freaking tired, especially for a couple of days after shot day. I am on 2.5mg weekly and my husband is on 4mg and reports the same. I combat it with NAD+ for more immediate energy and Epitalon for sleep. You have to make sure you are getting enough food for energy (protein and carbs) not to mention make sure it is actual fatigue and not anhedonia which is also very much a reta side effect! But it wasn't like I was the energizer bunny before I was on it.