Impact of an over-the-counter sleep lotion on salivary melatonin levels and sleep quality: a randomized controlled trial
Abstract
Many over-the-counter products such as bubble baths, room sprays, and lotions claim they contain the pineal hormone melatonin and promote sleep. In this randomized, controlled, double-blind crossover trial we compared the impact of a commercial sleep lotion versus a placebo control lotion. Our sample of 63 undergraduate college students scored an average of 6.3 {+/-} 2.7 on the Global Pittsburgh Sleep Quality Index, with 65% above the cutoff of 5 indicating poor sleep quality in the previous 30 days. Participants applied lotions on two different nights, one hour before bedtime. To assess whether melatonin was absorbed through the skin and circulating systemically, we conducted enzyme linked immunosorbent assays on saliva samples to quantitate melatonin levels. We also assessed sleep quality the night after lotion application with a modified Pittsburgh Sleep Quality Index. The melatonin-containing sleep lotion dramatically impacted salivary melatonin levels, increasing them up to ~1000 fold compared to the placebo control lotion. Sleep quality in the overall group was not impacted by the lotion, but in a subsample of the poor sleepers, the lotion improved sleep quality. High Performance Liquid Chromatography of the sleep lotion revealed the presence of 2.4 {+/-} 0.1 mg melatonin/g lotion, or a 0.24 {+/-} 0.01% formulation. Caution should be taken by consumers using over-the-counter melatonin lotions because the undisclosed dosage is high and well absorbed by the skin.…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design.
Read the paper
Related studies
- Tryptophan Metabolism and Gut-Brain Homeostasis
- Rationale for a Multi-Factorial Approach for the Reversal of Cognitive Decline in Alzheimer’s Disease and MCI: A Review
- Prioritized Research for the Prevention, Treatment, and Reversal of Chronic Disease: Recommendations From the Lifestyle Medicine Research Summit
- Relationship between sleep disorders and gut dysbiosis: what affects what?
- The role of CLOCK gene in psychiatric disorders: Evidence from human and animal research
- Genetic, Transcriptome, Proteomic, and Epidemiological Evidence for Blood-Brain Barrier Disruption and Polymicrobial Brain Invasion as Determinant Factors in Alzheimer’s Disease
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.