Medication in system doubles when it reaches it's steady state (5 half lives of that specific medication). So if you took 100mg of test cyp/ week, the milligrams in your body would constantly be increasing until roughly 40 days go by. That means at 40 days, you will have 200mg in your system, not 100mg anymore. So if you don't feel anything that great even after a few weeks on a specific dosage of testosterone, just be patient. Your total testosterone should constantly be increasing from day one until day 40. So with test cyp, only make dosage changes after 40 days of being on that specific dosage and frequency. This is why people always say it takes testosterone sometimes 3-6 weeks to “kick in”. It has to do with your receptors getting acclimated to these new testosterone levels, but it also has to do with the fact that maybe that 100mg in your system when you started didn't really make you feel that great or raise your testosterone levels high enough, but after 40 days (5 weeks), you now have 200mg in your system and your total testosterone should now be doubled from when you first started, and this amount of milligrams in your system might be just what you needed to feel good and get your numbers where they should be. Just think about it, 5 weeks is right there in-between 3-6 weeks. It makes perfect sense that people start feeling it around then, this is exactly when your body reaches a “steady state” on testosterone cypionate.