A quick investigation shows that the main active ingredient common to such products is L-ARGININE HCL - a non-essential amino acid which becomes essential with stress, injury or starvation, pregnancy & protein deficiency. So, I would conclude that ya just buy this in it's pure form which would be more cost effective, or ya just eat a shitload of meat, nuts, eggs, milk, & cheese which contain L-ARGININE. It may not taste as good, but hey, it's volume not quality we care abt.
warning : side effects may include chronic fratboy syndrome, tendency to lust after female siblings with baby fat.
</unqualified advice>