Is it true that you're not supposed to break time release capsules, and if so, why?

Defeats the purpose: Time release capsules are specifically designed to release a medication at a certain rate and therefore result in a target dose in the blood over a certain time span. By breaking the capsules, these precise conditions are disrupted and there's no guarantee about your dosing. Take this online course to learn more: http://pharmlabs.unc.edu/labs/capsules/objectives.htm

Time release caps: Time release capsules are designed to slowly release medication over long period of time. When the body of the capsule or tablet is disrupted, the structures intended to regulate the release is destroyed, and medication is delivered to the body at a much higher and faster rate than intended. This not only affects the function of the medication, it can be dangerous.

Yes.: Time release capsules are designed to release medications at a certain rate over a certain period of time. If you break them open, that effect is ruined and the medication will be released at an unpredictable rate and probably too fast.