Selective Androgen Receptor Modulators (SARMs) can improve Libido.  They are also capable of  building muscle;promoting bone growth/strength.  Similar to testosterone but with no verilization (can be used by women);no acne;no prostate cancer risk.  The administration is  via pill.
 
Ostarine is presently in PhaseII testing by a GTx,Inc.  Merck has agreed to market and  help develop  the drug.
Phase III is now in it's early planning stages.  
 
I have some rats ready for  testing.

Wonder how to get in on those Phase III trials...