It's easily purchased by the name of "l-tyrosine".
It's
far easier to get than 5-HTP, unfortunately I'm not sure of the price... Fill us in Mirage!
I don't think it increases the "speediness" of a pill what so ever. Remember that pills tend not to exhaust your dopamine supplies, as there's still enough dopamine around after MDMA for neurotoxicity to occur... So putting more in there shouldn't make any difference to the effects you feel. Kinda like filling up a fuel tank, while it's still half full. There's probably more benefits in using l-tyrosine for methamphetamine pre/post loading.
As for substitutes, phenylalanine is a precursor to l-tyrosine. It consists of l-phenylalanine (a stimulant, appetite suppressant, and antidepressant) and d-phenylalanine, which is a pain reliever. Phenylalanine it's self produces norepinephrine, a neurotransmitter depleted by stress, caffeine, nicotine, pollution, and some drugs... It also helps replace dopamine, as our bodies turn a small portion of it into l-tyrosine. So clearly it's not as efficient for replacing dopamine as l-tyrosine, as you'd be taking it to create l-tyrosine!
Take note - you have to have significant amounts of vitamin B6 and vitamin C in your blood stream in order for phenylalanine or tyrosine to work. 150-200 mg of Vitamin B6 and 1,000 to 2,500mg of vitamin C daily throughout the day should do the trick.

[ 22 August 2002: Message edited by: apollo ]