Melatonin is a hormone found naturally in the body. Melatonin used as medicine is usually made synthetically in a laboratory. It is most commonly available in pill form, but melatonin is also available in forms that can be placed in the cheek or under the tongue. This allows the melatonin to be absorbed directly into the body. Some people take melatonin by mouth to adjust the body’s internal clock. Melatonin is most commonly used for insomnia and improving sleep in different conditions. For example, it is used for jet lag, for adjusting sleep-wake cycles in people whose daily work schedule changes (shift-work disorder), and for helping people establish a day and night cycle.

How does it work?

Melatonin’s main job in the body is to regulate night and day cycles or sleep-wake cycles. Darkness causes the body to produce more melatonin, which signals the body to prepare for sleep. Light decreases melatonin production and signals the body to prepare for being awake. Some people who have trouble sleeping have low levels of melatonin. It is thought that adding melatonin from supplements might help them sleep.

There are actually two things going on that make sleep such a potent antioxidant:

  1. Melatonin is the most powerful mitochondrial antioxidant. Melatonin — the hormone our brain secretes to trigger sleep when it gets dark — is an incredibly potent and very unique kind of antioxidant. Importantly, unlike vitamin A, C, E and virtually all other antioxidants, melatonin is able to get into the mitochondria, where protecting cells from oxidative damage (free radicals) actually matters. (Note: Virtually all studies on vitamin A, C, and E supplements have failed to show benefits on aging and disease prevention,[48] and researchers now suspect this is why – because these antioxidants can’t get to the part of the cell where it really matters, the mitochondria.)
  2. Melatonin regulates and amplifies autophagy and mitophagy. Autophagy is the process where cells chemically digest and recycle broken down and dysfunctional cell parts and then rebuild new healthy cell parts. Mitophagy is the same basic process, but specifically localized in the mitochondria. These processes have now been recognized as being absolutely critical to the prevention of numerous diseases (including protecting against cancer) and even the aging process itself. In addition, without mitophagy functioning optimally, you are functioning TODAY on YESTERDAY’S broken down and dysfunctional mitochondria. Over time, that means less energy. So, the process of mitophagy is absolutely vital for optimal cellular energy production.
  3. Melatonin builds the almighty internal antioxidant defense system. Even more important than any antioxidant we might consume in food or in a supplement (and even the direct antioxidant effects of melatonin) is our cells’ own internal antioxidant defense system. And it turns out that every night while you sleep, this cellular antioxidant defense system regenerates and replenishes its supply of antioxidants for the coming day.[guess what happens when you don’t sleep enough, or you sleep poorly? Of course, your mitochondria are chronically operating with low supplies of internal antioxidants, so they are chronically getting damaged. And when they’re chronically being damaged, they’re going to shut down energy production and focus all their energy into Defense Mode to protect themselves against threats.

Melatonin is essentially the mitochondrial antioxidant, and ancient one at that.

“Melatonin may be considered as a mitochondrial antioxidant because it not only directly scavenges and indirectly neutralizes free radicals, but it also reduces radical generation in mitochondria, via a phenomenon known as radical avoidance. To achieve radical avoidance, melatonin accelerates the electron flow through the [electron transport chain] and slightly activates the [mitochondrial permeability transition pore]. This may explain why melatonin is more protective of mitochondria against oxidative stress than other antioxidants. Studies have documented that melatonin restores the mitochondrial functions in aged animals and in animals with different pathological conditions.

Melatonin is quite possibly nature’s most versatile biological signal. It has been found in all major types of organisms — not just animals, but also plants, algae, fungi, and even bacteria. In fact, melatonin is believed to have appeared over 3 billion years ago in photosynthetic bacteria, where it protected against oxidative stress.