There’s a common misconception that all sexual issues are psychological. In reality there’s a complex interplay between physiology and psychology. I’ve known several people (women and men) who’ve suffered significant declines in libido and the tell-tale factor was an associated decline in overall mood and energy; the decline was simply more obvious with regards to sexual desire because one can use caffeine to somewhat off-set the impact in other areas. The underlying cause in all these cases? A decline in the body’s production of testosterone. Although males on average produce around ten times as much as women the effect is the same in both genders: increased energy, increased libido, slightly decreased immune function. In all the cases I’ve known, either a short treatment with testosterone patches or consumption of DHEA (of which a very small fraction will be converted by the body into testosterone) has resulted not only in the return of normal sexual feelings but also in elevated mood and energy levels.