Melatonin: The Benefits vs. the Risks of the Dietary Supplement

posted in Life Sciences

Melatonin was first identified by Aaron B. Lerner, an American physician and dermatologist at Yale University, in 1958. Dr. Lerner and his colleagues were initially investigating a cure for vitiligo, an autoimmune disorder characterized by the loss of skin pigmentation. Although the experimentation failed to find a cure for skin disorders, subsequent research revealed that the compound melatonin did have a profound impact on the brain and neuroendocrine systems. The discovery paved the way for melatonin's widespread use as a sleep aid for humans.    

What is Melatonin?

Melatonin, a hormone produced by the pineal gland, plays a crucial role in regulating our body's internal clock. The pineal gland releases melatonin into the bloodstream via nerve terminals, particularly at night, to help us maintain our circadian rhythms and adjust to seasonal changes. This natural process is key to understanding the role of melatonin in our body's sleep-wake cycle. In addition to its natural production, melatonin is also available as a synthetic dietary supplement, typically as an oral tablet or capsule. 

Despite its widespread use, it is crucial for consumers to understand the potential adverse effects of dietary supplements. Unlike prescription drugs, dietary supplements like melatonin are not regulated by the U.S. Food and Drug Administration (FDA). This lack of oversight means that the content, quality, and safety of these supplements can vary significantly from product to product, so it's important to be cautious when using them. It's always advisable to consult a healthcare professional before starting any new supplement.

The Potential Benefits of Melatonin

According to medical experts at Rush University, an estimated 40 million Americans cope with some degree of insomnia each calendar year. While research continues to determine melatonin's effectiveness in improving sleep quality and total sleep time, individuals with insomnia or chronic sleep disorders have reported positive feedback on its use. Those with chronic insomnia and delayed sleep-wake phase sleep disorder have found that the time needed to fall asleep was greatly reduced after using melatonin. This potential benefit of melatonin offers a ray of hope for those struggling with sleep issues, empowering them to make informed decisions about their health. 

The Potential Risks of Melatonin

Significant side effects and risks should be considered when exploring the uses of melatonin, specifically when combined with other medications. For example, when melatonin is taken with blood thinners like warfarin, the risk of bleeding may increase. Similarly, combining melatonin with blood pressure control medicines, such as Procardia XL or Procardia, may lead to elevated blood pressure, posing risks of heart disease or stroke. Additionally, melatonin can interact with antidepressants and contraceptive medications, leading to excess levels of melatonin in the body. Higher than normal levels of melatonin can result in headaches, vivid nightmares, irritability, stomach pain, daytime drowsiness, and nausea.

Additionally, although research indicates there may be sleep benefits for children with attention-deficit hyperactive disorders or autism spectrum disorders, it is crucial to consult a pediatrician for appropriate dosage. Children may experience side effects such as bedwetting and agitation, in addition to headaches and drowsiness. From 2012 to 2021, the number of calls about pediatric melatonin ingestions to the U.S. Poison Control Centers jumped by 530% to more than a quarter million calls.

Mislabeling and Ingredient Issues

Recent studies have highlighted concerns regarding the accuracy of melatonin labeling, particularly in gummy products. The study indicated that these products contained significantly higher amounts of melatonin than indicated on the label, some exceeding the listed amount by 347%. Another instance revealed that unlabeled ingredients, such as cannabidiol (CBD), were mixed into the batch of gummies. The study conducted by the Cambridge Health Alliance indicated that 22 of 25 (88%) sampled gummy products were mislabeled, with one product containing no melatonin but detectable levels of CBD. In other instances, suppliers may import foreign raw materials, leaving end users uncertain if the ingredients are measured and accounted for as advertised.

Reducing Risk

There are a handful of ways that consumers can reduce the risks mentioned above. 

  1. Consult your healthcare provider. Talk to your doctor or pharmacist before starting melatonin, or increasing your dosage or frequency, or combining with other medications, especially if you have other medical conditions. 
  2. Be cautious with children. Dosage levels and long-term effects on children are still not well understood. Consultation with a pediatrician is recommended before beginning melatonin with any child. 
  3. Buy from reputable sources. As with any drug or dietary supplement, opt for well-known retailers and pharmacies over unknown sellers.
  4. Look for certifications. Because melatonin is sold as a dietary supplement and is not approved by the FDA, consumers can opt to choose products that have been tested and verified by independent organizations such as the U.S. Pharmacopeia (USP), NSF International, or other similar certifying organizations. Such certifications help ensure the supplement contains what is listed on the label.
  5. Read the label. Look for clear information on dosage and ingredients. Be wary of exaggerated and unscientific claims. Review and understand warnings and instructions for use.
  6. Start low. Consumers should generally start with lower doses, typically 1mg or lower, and then increase gradually as needed. Experts generally recommend taking no more than 10mg of melatonin within a 24-hour period.
  7. Be aware of side effects. Become familiar with common side effects of melatonin and discontinue use and consult a doctor if you experience any persistent side effects.
  8. Avoid long-term use without medical direction. Short-term use is generally considered safe, but long-term, consistent, everyday use is not well studied and is not generally recommended.


There are risks and potential adverse effects for melatonin products. A lack of stringent FDA regulation increases the likelihood of undeclared ingredients and inaccurate labeling. However, for the cautious and informed consumer, melatonin is still a promising and helpful supplement for the sleepless.

Authored by Jack O’Keefe, Berkley Life Sciences, Life Science Associate

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