Matters are interrelated. And the key for a whole series of events and mental states is how much dopamine the dopaminergic neurons in the substatia nigra of the brain secrete.
L-dopa is the precursor which dopaminergic neurons use to synthesize dopamine.
More L-dopa means more dopamine.
More dopamine means lower prolactine.
Lower prolactin means more sexual desire and better fertility.
See science here:
Journal: Fertility and Sterility
Volume 92, Issue 6, December 2009, Pages 1934-1940
Mucuna pruriens improves male fertility by its action on the hypothalamus–pituitary–gonadal axis
To understand the mechanism of action of Mucuna pruriens in the treatment of male infertility.
Seventy-five normal healthy fertile men (controls) and 75 men undergoing infertility screening.
High-performance liquid chromatography assay for quantitation of dopa, adrenaline, and noradrenaline in seminal plasma and blood. Estimation by RIA of hormonal parameters in blood plasma, namely T, LH, FSH, and PRL. Main Outcome Measure(s)
Before and after treatment, serum T, LH, FSH, PRL, dopamine, adrenaline, and noradrenaline in seminal and blood plasma were measured.
Decreased sperm count and motility were seen in infertile subjects. Serum T and LH levels, as well as seminal plasma and blood levels of dopamine, adrenaline, and noradrenaline were also decreased in all groups of infertile men. This was accompanied by significantly increased serum FSF (follicle-stimulating hormone) and PRL (prolactin) levels in oligozoospermic subjects.
Treatment with M. pruriens significantly improved T, LH, dopamine, adrenaline, and noradrenaline levels in infertile men and reduced levels of FSH and PRL. Sperm count and motility were significantly recovered in infertile men after treatment.
Treatment with M. pruriens regulates steroidogenesis and improves semen quality in infertile men.