Melatonin: Dosage, Reviews & Safety

Melatonin is a hormone found naturally in the body and made synthetically that promotes sleep. It is also a popular supplement used for promoting sleep and treating insomnia. Like all supplements and medications, there are indications, contraindications, dose recommendations, dosage, reviews, safety profiles, effects and side-effects that users should know about.

It is used as a supplement and is usually made synthetically in a laboratory. It is often available in pill form, but it is also available in forms that can be placed in the cheek or under the tongue. This allows the melatonin supplement to be absorbed directly into the body. (1)

People use melatonin supplements to adjust the body’s internal clock. It is used for jet lag, for adjusting sleep-wake cycles in people whose daily work schedule changes (shift-work disorder), and for helping blind people establish a day and night cycle.

Melatonin Benefits for Sleep

• Naturally made
• Low side-effect profile
• Much scientific evidence showing efficacy

What Is Melatonin and What Is it Used For?

Melatonin , chemically N-acetyl-5-methoxytryptamine, is a substance found in animals, plants, fungi and bacteria. In animals it is a hormone that anticipates the daily onset of darkness; however in other organisms it may have different functions. Likewise, the synthesis of it in animals differs from that in other organisms.

The chemical formula of melatonin: C₁₃H₁₆N₂O₂

In animals, melatonin is involved in the (synchronization of the circadian rhythms of physiological functions including sleep timing, blood pressure regulation, seasonal reproduction and many others. Many of it’s biological effects in animals are produced through activation of melatonin receptors while others are due to its role as a pervasive and powerful antioxidant, with a particular role in the protection of nuclear and mitochondrial DNA.

The hormone can be used as a sleep aid and in the treatment of some sleep disorders. It can be taken orally in liquid form as well as capsules or tablets in immediate- or prolonged-release form. It is also available in a form to be used sublingually, and as transdermal patches. Melatonin is sold as an over-the-counter sleep aid in the U.S. and Canada. In other countries it may require a prescription or it may be unavailable. (2)

In recent times, melatonin has become available as a drug and a dietary supplement to get better sleep. It appears to have some use against insomnia, jet lag, and circadian rhythm disorders. Melatonin is a powerful antioxidant which can easily cross cell membranes including the blood-brain barrier. It has been studied for the treatment of cancer, immune disorders, cardiovascular diseases, depression, seasonal affective disorder, and sexual dysfunction; the results of most of these studies remain inconclusive. However, it has been shown to clearly ameliorate seasonal affective disorder and circadian misalignment, in studies by other researchers.

Melatonin is referred to by some biochemists and human physiologists as the master hormone, because it regulates the production of most human hormones, both paracrine and endocrine. In addition, taken alone, is an immunoregulator that enhances T cell production somewhat. However, when melatonin is taken in conjunction with calcium, it is a very potent immunostimulator of the T cell response. This is the reason it is used extensively as an adjuvant in many treatment protocols. Because it does not have to be prescribed, and since it is in the public domain, few doctors care to publicize its advantages. For the same reason, few clinical trials have been done to see its effectiveness in treating various diseases, such as cancer, obesity, h.i.v. infection, and others. (3)

Melatonin Dosage for Sleep

The dosage of melatonin may range from 0.3 to 3.0 milligrams.

Light therapy may advance the phase about one to two-and-a-half hours and an oral dose of 0.3 or 3 mg, timed correctly a few hours before bedtime, can add about 30 minutes to the ~2 hour advance achieved with light therapy. There is no difference in the average magnitude of phase shift induced by the two doses (0.3 or 3 mg).

Melatonin Reviews

It is important to realize that melatonin is sold over the counter and that the FDA (U.S. Food and Drug Administration) does not evaluate these products for efficacy. They take action against companies that misbrand their products or adulterate them.

There are very few or large research studies that assess the efficacy of different brands.

Most reviews of melatonin products come from individual consumers who have not participated in a randomized and ‘double-blind’ trial to determine efficacy of the products. Therefore, most melatonin reviews on the internet are not scientific in nature.

Is Melatonin Safe?

Melatonin taken with MAOI drugs can also lead to overdose because MAO is inhibit the breakdown of it by the body. Fortunately, melatonin exhibits almost no toxic side effects, except for the occurrence of somnolence in most of the population at higher doses. There are as of yet no reports about melatonin toxicity, notwithstanding the dosage administered, nor the amount of time the medication has been taken, except for clinical changes as noted in various studies. Exogenous melatonin does not affect the endogenous profile in the short or medium-term. There have not been sufficient studies done on pregnant women concerning possible carcinogenic effects of melatonin.

Insecticides Increase Risk Of Metabolic Disease By Mimicking Melatonin

New research has found that the synthetic chemicals that make up pesticides affect our biological clocks by binding to the receptors that govern them. In these findings, it is noted that exposure to these chemicals has a negative impact on melatonin receptors, which put individuals at higher risk of metabolic diseases like diabetes.

For the sake of understanding the chemicals’ effects, this research focused on just two: carbaryl and carbofuran. Carbaryl is the third most popular insecticide used in the United States, and carbofuran is the most toxic insecticide on the planet. Carbofuran is banned from use on food crops meant for human consumption. Unfortunately, other countries like Mexico still use it in trace amounts on plants and wildlife.

This research shows that further studies are needed to look at how environmental chemicals disrupt circadian activity, which is currently not considered by federal regulators. The team of researchers are creating a bioassay to assess these chemicals more closely.

These findings lead the researchers to conclude that this direct interaction with the melatonin receptors means that chemicals like carbaryl can disrupt physiological processes and circadian rhythm, while also altering metabolic function. This increases the risk of metabolic disorders like diabetes.

Melatonin Summary

In summary, melatonin is an important part of normal sleep-wake homeostasis in all mammals. Synthetic supplements are commonly used as a sleep-inducing aid. Research has demonstrated conflicting evidence about the efficacy of melatonin for the treatment of certain sleep disorders.

• About
• Latest Posts

Physician Reviewed M.D.

Sleep Physician at American Sleep Association Reviewers and Writers

Board-certified sleep physicians, scientists, editors and writers for ASA.

Latest posts by Physician Reviewed M.D. (see all)

• Ask The Sleep Doctor:How Common is Sleep Apnea, Vagal Nerve Stimulators, Ambien and More - October 25, 2018
• Ask The Sleep Doctor: Sleep Apnea in Child, Depression and Sleep, MVA and OSA, Morphine & Sleep - September 2, 2018
• Ask The Sleep Doctor: What about 6 Hours of Sleep? Depression and Sleep Apnea? Traveling with CPAP? - August 28, 2018