You don’t feel pain, they can show inside of the human body in a easy and effective way.
There are obviously A LOT of them. Like how your brain is slowly deteriorating, which is scary and dangerous. I can't cover everything but I have a website link you could visit that talks about this subject
https://www.drugabuse.gov/publications/research-reports/heroin/what-are-long-term-effects-heroin-use
Check the file I added, Brainly wouldn't let me comment my answer for some reason.
<span>The depressant effect alcohol become apparent at a blood alcohol concentration of
</span>0.10%.