The “sleep hormone” comes in pill form, but in what situations does it really help a person snooze? Yahoo Health tackles the subject of melatonin.

In some circumstances, a small dose of melatonin — 1 to 3 milligrams — can boost your sleep quality. A new study in the journal Critical Carefound that in a simulated ICU environment, people who were given a milligram of melatonin woke up fewer times throughout the night, had improved sleep quality, reported lower anxiety, and experienced increased REM sleep compared with people who only used an eye mask and earplugs.

But experts caution against broadening results like that. “I don’t think melatonin helps promote better sleep in general,” W. Christopher Winter, MD, medical director of the Sleep Medicine Center at Martha Jefferson Hospital, tells Yahoo Health.