Complex sentence: They designed a study as follows: they would give the participants an injection of epinephrine (adrenaline), although all participants were told that they were given a new drug called "Suproxin" to test their eyesight.
Split into simpler sentences: They designed a study as follows: they would give the participants an injection of epinephrine (adrenaline). Although, all participants told that they were given a new drug called "Suproxin" to test their eyesight.