Ok,
for years I did adderall and then meth because I would play so much music, write music and sing at the top of my lungs.... it was sooo euphoric.... fast forward about 8 years,,, my lungs have lost so much capacity from smoking the stupid shit, the confidence and clear tone I used to generate totally went by by.... i may have damaged my vocal chords from the harsh meth smoke.... I became addicted and unhealthy and started using opiates at the come down....
I was like you , i totally get it.... but its basically using you up , like everytime you get high on meth and sing, you only got so many more times you can do that before youre gonna burn out everything ... personally I don't see it as a totally physical thing, but a spiritual connectiong thing too....
If you are gonna do this, heres some things to keep in mind..... first of all warm up , drink tons of water... DON'T SMOKE METH, IT IS THE WORST DRUG FOR YOUR LUNGS AND VOICE AND MUSCLES!!!! Try putting a little bit in a capsule! This is how I do it now, and I like it better than smoking or snorting.... (Smoking was my obsession for awhile, I loved meth pipes, but it totally gets old and gross the longer you do it) Make sure you HYDRATE PLENTY! Put a humidifyer in your room , to lube up your vocals with moisture while you sleep. Watch videos on youtube about proper technique and breathing, so you don't sing incorrectly and damage your voice over time, (I think this is what happened to me, years of singing with too much stress in the neck instead of the diaphram)
I used to be a pretty cool band, and we would tour and meth was totally my thing, I got everyone in the band into doing meth. After awhile going up on stage on meth was horrible, it made me all jittery and short-breathed , nervous, Because you already have a rush from the thrill of being up in front of people, you don't need to throw more stimulation on top of that. Then I discovered heroin, and trust me if you think meth is good for singing, heroin is like 5 times as good.... it changes your tone, relaxes your voice so your tone sounds SOOO sweet! These days I use stimulants for SONG WRITING, and OPIATES for performing, and BOTH FOR recording!
good luck!