Most melatonin pills do not contain the dose listed on the label.
Last month in the Journal of Clinical Sleep Medicine, University of Guelph researchers Erland and Saxena reported that 71% of the thirty common melatonin products they purchased in local grocery and drug stores deviated more than 10% from the dosage listed on the label.
Some of these non-prescription capsules, tablets, liquids, and strips had up to 83% less melatonin than listed, while others had up to 3 – 5 times more than labeled.
Erland and Saxena also found that 25% of the supplements also contained unlabelled serotonin. In some cases this may be explained by the presence of herbal extracts, but it’s difficult to account for the presence of serotonin in the supplements that didn’t contain herbal extracts. Serotonin is not regulated for sale as a supplement because its side effects may cause serious health concerns.
Melatonin is our body’s sleep chemical, the one that prompts us to fall asleep. It is a hormone made and released 12 – 14 hours after we wake up. We produce less of it after age 40.
Medicinal plants also produce melatonin. Differing batches or mixing procedures may account for some of the variation found between the dosage listed and what was actually in the supplements.
But the wide variations between the advertised dose and the amounts actually in these products shows melatonin labelling to be very unreliable.
Melatonin is helpful to more quickly recover from jet lag or adapt to a new schedule in shift work. However it fails as a “sleeping pill” because most of the time it does not decrease insomnia. (Cognitive behavioural approaches like those in the Better Sleep Program are more effective at decreasing insomnia.)
The best way to find out if over-the-counter supplements are helpful to you is to record the data. Keeping a sleep diary for 3 – 4 weeks can help you determine if a particular brand of supplements, herbal sleepy time teas, or new sleep routines are having any impact on your sleep.