I'll give you what I have...however flawed it may be.
Here is a fairly relevant article....
http://www.mesomorphosis.com/article...l-function.htm
From what I have been reading, I gather the following:
Deca suppresses endogenous testosterone, which is much more androgenic than the deca. It is the androgenic property of test that benfits the libido. It actually stimulates gonadotropin production, which in turn affects libido.
All that is well and good, but too much of a good thing is actually a bad thing. DHT derivatives tend to decrease libido as is evident in the sides effects of Propecia. So how can more test make it better?
Deca interepheres with the hpta in a greater capacity than does test. The hpta plays a very large role in libido.
So, simply replacing your endo test with exo test while deca has your hpta crashed...should do very little in the way of kickstarting your libido.
The question this begs is, how then would a further increase is exo test circumvent the negative feedback of the hpta. That is where I stand with this off the wall answer. I'm really tired and this probably won't make any sense in the morning.
Like I said, I'm just throwing out ideas.