At the same time (and I've seen this mentioned in some of the andro research), the conjugation enzymes in the liver and intestines seem to be overwhelmed so to speak during the first 4-5 weeks. But then fight back.
Negative feedback mechanisms are a bitch aren't they.
This is why in our cycle outlines we don't suggest a cycle length over five weeks.
At lot of this is more theory of course. I like talking about it though.