This lead to the discovery that the amino acid cysteine creates hydrogen sulfide and injecting rats with it also resulted in erections. It seems it maybe a cGMP-specific phosphodiesterase type 5 (PDE5) inhibitor.
To date no new drugs have resulted from this discovery but in the meantime M&F recommends supplementing with 1-3 grams of L-cysteine about an hour before the show starts.
"Rotten eggs & erections. " Joe Weider's Muscle & Fitness. 71.3 (March 2010): 51(1).
Probing erectile function: S-(2-boronoethyl)-L-cysteine binds to arginase as a transition state analogue and enhances smooth muscle relaxation in human penile corpus cavernosum.
Sildenafil effect on the human bladder involves the L-cysteine/hydrogen sulfide pathway: a novel mechanism of action of phosphodiesterase type 5 inhibitors.
S-allyl cysteine restores erectile function through inhibition of reactive oxygen species generation in diabetic rats.
Penile erection in the primate: induction with nitric-oxide donors.
Role of Arginase in the Male and Female Sexual Arousal Response