@Brandon9000,
Brandon9000 wrote: but I definitely want some of the drug if it works
I probably would too. But it leads to a lot of odd situations.
For example, what if you were 40yrs old and your parents took the drug and reverted to the appearance and activity level of 20yr olds. How would that feel, for them and for you?
And what if you were 90yrs old and reverted to a fitness level of 30yrs old yet retained all of your wisdom and experiences. Who would you hang around with? Would you be more comfortable with the 30yr olds or the 90yr olds?
I think you're right that it would be chaos until society adjusted.