Where are you getting you information????

The only detrimental effect that pot has on you is similar to cigarettes.
If you smoke too much, your throat gets raw, you cough up phlegm and get a tickle in your throat. Just like cigarettes.
The thing you can do is find ways to smoke it so it goes down smoother.
Bongs, supertokes and best of all, in moderation.
Don't suck them down like a milkshake.