I think this is the right place to post this (first thread).
This study shows that pde5 inhibitors enhance phase advances (waking up earlier and going to sleep earlier) in response to morning ligh exposure.
http://journals.plos...al.pone.0037121
I ordered some icariin to try this out. Unwanted erections could be an embarassing side effect, depending on the dose taken.
My current understanding is that evening cGMP (induced by pde5 inhibitors) does not have a negative effects on sleep. It is also my understanding that cAMP (induced by forskolin or pde4 inhibitors) enhances/induces melatonin production. Here is an interesting study regarding melatonin and forskolin.
http://onlinelibrary...250411/abstract
Additionaly, melatonin inhibits cAMP.
http://www.ncbi.nlm....pubmed/19215498
I would like help understanding the relationship between cGMP, cAMP, and sleep. Based on my current understanding, increasing cGMP in the morning should drasticaly enhance sleep schedule and//or quality. Avoiding evening light is also good, but not very practical in this modern age (for me at least).