Instruct: Classify Amazon reviews into positive or negative sentiment
Query: This is a dangerous book.

Melatonin is not a miracle. It is a hormone whose secretion governs your circadian rythm. In other words, it makes you sleepy at night, when your body naturally generates it.Taking melatonin to improve your skin tone, and use it as an all around fountain of youth miracle drug is nonsense. The more melatonin you take, the more you screw up your internal hormonal secretion of melatonin.Also, the dosage recommended are far higher than what is prudent to take.Whenever someone touts something as a miracle it is always too good to be true. This book is certainly no exception.