According to a crossover study, young, healthy people using weighted blankets have higher melatonin levels in their saliva before falling asleep. Researchers wanted to explore if wearing a heavier blanket at sleep (about 12% of body weight) led to greater salivary levels of melatonin and oxytocin than using a lighter blanket (about 2.4% of body weight).

Duration of sleep, subjective sleepiness, activity of alpha-amylase in saliva (as an indicative metric for sympathetic nervous system effect), and stress hormone cortisol were all investigated for potential variations. The one-hour salivary melatonin rise from baseline (i.e., 22:00) to lights off (i.e., 23:00) was around 32% greater when a weighted blanket was used, as shown in Figure 1:

Overall sleep duration and subjective sleepiness were the only other variables that did not change significantly across the blanket conditions. A weighted blanket may cause a greater melatonin release at bedtime. Future research should look at whether utilizing a weighted blanket often over a period of weeks or months has a consistent stimulatory impact on melatonin production. Researchers need to explore whether the observed rise in melatonin is therapeutically significant for the weighted blanket's previously mentioned effects on anxiety and insomnia.