The Study
Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content
This study is like a lab test that checks what ingredients are actually inside a box of pills. It can tell us exactly how much melatonin is in each pill and whether serotonin is present, but it cannot tell us how the pills will affect a person's sleep or health.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Scientists tested 31 popular sleep supplements to see if they actually contained the right amount of melatonin and checked for hidden ingredients. They found that most pills did not match their labels, with some having way too much or too little, and a few contained a different brain chemical called serotonin that was not listed.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 529 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes, this is highly significant for consumers and clinicians because it means people cannot reliably trust over-the-counter melatonin dosages or safety, potentially leading to ineffective treatment or unexpected side effects.
- 2Melatonin amounts ranged from 74% to 347% of what was on the label, with some containing none.
- 3Same brands varied by up to 465% between batches.
- 426% of pills contained hidden serotonin (1-75 micrograms).
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Clinical Sleep Medicine
Year
2017
Authors
Lauren A. E. Erland, P. Saxena
Related Content
Claims (5)
Many over-the-counter melatonin pills don't actually contain the amount of melatonin listed on the bottle. In fact, some have way more, some have way less, and a few don't have any melatonin at all.
The amount of melatonin in the same supplement brand can vary wildly from one batch to the next, sometimes by over 400%. This means you can't really trust that you're getting the same dose every time you buy it, even if it's the exact same bottle.
Some melatonin pills contain unlisted serotonin, and this isn't just because of added herbs. It's likely caused by factory mix-ups, chemical breakdowns, or poor quality control during manufacturing and packaging.
The amount of melatonin in store-bought sleep aids often doesn't match what's printed on the label. In fact, many pills contain way more or way less than advertised, making it hard to know exactly what dose you're actually getting.
Serotonin, a potent neurotransmitter and strictly controlled substance, is present as an unlabelled contaminant in approximately 26% of commercial melatonin supplements, with detected concentrations ranging from 1 to 75 micrograms per dose. The presence of this biologically active compound in sleep aids raises significant safety concerns, particularly regarding potential adverse interactions with other medications or the risk of serotonin syndrome in sensitive individuals.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.