In today's episode, Matt takes us on a deep dive into melatonin. He covers four main topics: 1) what is melatonin? 2) how does melatonin work? 3) what does melatonin do, and *not* do, for sleep? 4) how can we think about melatonin supplementation? First, Matt describes that melatonin is a naturally occurring hormone released by the brain. He gleefully notes that melatonin is often called, “the vampire hormone” as it comes out at night. In doing so, it signals that it is nighttime, which in turn helps schedule sleep. Second, Matt explains that, during the day, light enters your eyes, and inhibits the release of melatonin. This absence tells your brain that it's daytime and time to be awake. Fast-forward to the evening, and the arrival of darkness, the floodgates of melatonin release open up. We need darkness in the evening to trigger this release, and, in turn, tell your brain that it's nighttime and time to sleep. Matt highlights one significant problem of the present age: we live in a dark-deprived society. Many of us get too much artificial light, and not enough darkness. He shares a tip to dim down half of the lights an hour before bed and avoid screens. Third, Matt elaborates on what melatonin does and does not do; that is, melatonin helps schedule the *timing* of your sleep but does not significantly change the *quality* of sleep. He uses the analogy of a race, where melatonin would be the official who begins the great sleep race but does not participate in the race itself. Finally, Matt discusses supplementation. You can buy melatonin in certain countries to try to use it as a sleep aid. Based on scientific data across the past 15 years, Matt notes that melatonin isn't as effective as you may think: a recent meta-analysis discovered that melatonin only increases the speed with which you fall asleep by 3.9 minutes, and only improves your sleep efficiency by just 2.2%. This reinforces his point that the role of melatonin is primarily in regulating the timing of your sleep, not in sleep generation.  Matt states that melatonin is not well regulated as a supplement, and that the strength of melatonin that you buy is often unreliable. He describes a study that examined over 15 different suppliers. Strikingly, when tested, the concentration of melatonin within each pill ranged from 83% less to 478% more than what was stated. Finally, Matt advises that the best way to optimize your sleep is to rely less on melatonin supplementation, and instead, focus on the basics we know make a real difference: sleep regularity, keeping your bedroom cool, getting darkness in the evening, get plenty of natural daylight during the morning, do some physical activity each day, and perhaps most importantly, address your stress and anxiety. Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice, nor prescriptive in any way. The sponsors of this week's episode are InsideTracker. They are offering 25% off any one of their programs for anyone who uses the above link. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you. So, make your way over to InsideTracker, and take advantage of this incredible deal on this valuable and remarkably convenient service. And, as always, if you have thoughts or feedback you'd like to share, please reach out to Matt on Instagram.