Irregular sleep was not good in any study Among all the studies reviewed, irregular sleep was either neutral or harmful; none showed that irregular sleep was good for health or performance In some long‑term studies, each extra hour of fluctuation in sleep timing was linked to notably higher risk of metabolic syndrome and heart events.

Harvard Medical School researchers have consistently warned that the brain supplement market is fraught with problems. Dr. Pieter Cohen, a physician and associate professor at Harvard Medical School, identified a disturbing pattern: many over-the-counter brain supplements contain unlisted, unapproved pharmaceutical drugs that aren't legal in the United States.