I have always been suspicious of the bro science term "kicking in" of a drug starting to work weeks after it is taken. Anyone who knows anything about these hormones knows that they are utilized very quickly by the body. And then metabolized right out of the body. That is why they attach longer esters to the hormones.
In an article in the Dec.,2008 issue of Mus. Dev. Mag., titled Nutrient Timing of Whey Protein and Creatine Increases Muscle Growth, by Robbie Durand, MA. He reports on a study investigating the relationship between acute and 24 hour changes in muscle protein metabolism.
The difference between rest and exercise was identical whether measured over 3 hours or 24 hours. These results support the contention that acute changes in protein synthesis after resistance exercise represent small changes that occur over longer periods of time, resulting in changes in muscle mass. Deposition of muscle protein following each bout of exercise is small and the accumulation of these small changes gradually increases muscle mass over a period of training. This gradual accumulation of new proteins may explain why changes in muscle mass with training are not measurable until several weeks of training.

So these drugs do not "kick in" after several weeks of use. That is how long it takes for noticeable muscle growth to occur. Any earlier "gains" is just water retention.