Melatonin (N-acetyl-5-methoxytryptamine) is an important neurohormone that readily penetrates cell membranes and exerts many beneficial biological functions for human health and well-being, including neuroprotective, immune-supportive, and anti-ageing properties. The best-known benefit of melatonin is its chronobiotic effect and its ability to regulate circadian rhythm, making it most commonly used for the treatment of sleep-related disorders such as insomnia, anxiety, and jet lag.

Melatonin health claims

Melatonin is found in both medicines and food supplements, as a single compound or in combination with vitamins, minerals, or herbal extracts. The European Commission has authorized two health claims proposed by the European Food Safety Agency (EFSA) for foods containing melatonin, stating:

-melatonin contributes to the alleviation of the subjective feelings of jet lag (0.5 mg/day)

-melatonin contributes to the reduction of time taken to fall asleep (1 mg/day)

While there is no official maximum recommended dose of melatonin for adults, a typical dose in supplements is between 0.5 and 5 milligrams, although whether this is appropriate for a particular person depends on individual factors such as age and sleep problems. This is important because lower doses could be ineffective and any variation in dose from night to night can be interpreted as a lack of efficacy. Higher doses, on the other hand, may lead to unpleasant and unexpected side effects, especially in people who are sensitive to it or who are taking medications that interact with melatonin.

In 2018, the French agency ANSES conducted an analysis of the 90 reports of adverse effects likely to be associated with the consumption of food supplements containing melatonin and issued a recommendation to restrict the use of melatonin products for people with any type of inflammation or autoimmune disease, pregnant women and nursing mothers, children, people with epilepsy, asthma, or mood, behavioural, or personality disorders.

Quality control

Compared to medicines, food supplements are generally considered safe and are not subject to such strict regulations regarding quality control and efficacy. Consequently, this leads to concerns about the actual concentrations of the active ingredients present in the food supplements, including melatonin. One study analysed 31 melatonin supplements and found that actual melatonin content ranged from -83% to +478% of the labelled content. Also, the content of melatonin between lots of the same product varied by as much as 465%. Other concerns include impurities and the presence of tryptophan related contaminants as well as serotonin, a breakdown product of melatonin metabolism, that can have harmful effects even at relatively low levels. In conclusion, without quality control, there is no guarantee of the strength or purity of melatonin supplements.

Several analytical methods have been used for the analysis of melatonin in various products and raw materials. The main limitation in the determination of melatonin is its low concentration, which requires the use of sophisticated and highly sensitive detectors. For food supplements where the amount of melatonin is higher, the major concern is the stability of melatonin in the formulation. It has been observed that melatonin can be unstable under certain storage conditions and in combination with other compounds, which can lead to degradation or alteration of the melatonin content in these formulations. Therefore, product quality supported by analytical data increases the value of the product and reduces manufacturing costs while ensuring the consistency and safety of the food supplements.

In our laboratory we perform analyses of melatonin content in various matrices. For more information about melatonin analysis, Contact us.