Ya its prison. Yes the guards are 'supposed to' do a lot of things for prisoners. Like, not beat them senseless, and rape them, and sell goods to them. But considering all these things happen....
As everyone else said, at best expect a tiny tiny fraction of your dose in the normal units, or stay in a medical unit locked with all the crazies and people escaping gen pop with no abilities to do anything what so ever.
Unfortunately not many people in this country give even 1 shit about prisoners, or their rights. In the past year I have read about several prisoners being beaten to death by guards, another prisoner who was tied up, blindfolded, raped, and left like this for over 24 hours in her cell, and countless other crimes and violations of basic human rights. Unfortunately it happens, the guards sometimes escape punishment, and do so because no one gives a shit enough about prisoners. Yes they get sued but its often settled for pennies on the dollar and no admission of wrong doing.
Prison system is a very very fucked up place. I know a few people who did long, long stays, in rikers and all around NY. And while they are doing well, they have told me some of the horrors of being in there.