Sleep Flow combines ingredients that have been studied for sleep and relaxation. Here is what the research says, including the limits. Studies used different forms and amounts than Sleep Flow, and results are mixed: some trials found a benefit, others did not.
Tart cherry
Sleep Flow provides 430 mg of Montmorency tart cherry concentrate per serving.
- Pigeon et al., Journal of Medicinal Food, 2010. A randomized, double-blind, crossover study in 15 older adults with insomnia. Tart cherry juice reduced time awake after sleep onset and insomnia severity compared with placebo. Time to fall asleep, total sleep time and sleep efficiency did not differ. Read the study
- Barforoush et al., Food Science & Nutrition, 2025. A systematic review of seven studies. Some reported better sleep measures. The authors describe the evidence as limited and varied. Read the review
L-theanine
Sleep Flow provides 150 mg of L-theanine per serving.
- Hidese et al., Nutrients, 2019. A randomized, double-blind, placebo-controlled trial in healthy adults taking 200 mg per day for four weeks. Sleep quality scores (PSQI) improved compared with placebo, including time to fall asleep and sleep disturbances. Read the study
- Bulman et al., Sleep Medicine Reviews, 2025. A meta-analysis of randomized trials (19 articles, 897 participants) found improvements in self-reported sleep onset, daytime dysfunction and overall sleep quality. The authors say more research is needed on dose and duration. Read the meta-analysis
Chamomile (a source of apigenin)
Sleep Flow provides chamomile extract, which contains apigenin. Most human research is on chamomile, not apigenin on its own.
- Adib-Hajbaghery & Mousavi, Complementary Therapies in Medicine, 2017. A randomized trial in older adults taking chamomile extract for 28 days. Sleep quality (PSQI) improved compared with placebo, while sleep duration did not increase.
- Hieu et al., Phytotherapy Research, 2019. A systematic review and meta-analysis found improved sleep quality with chamomile. Evidence on insomnia was limited. Read the review
- Kazemi et al., Complementary Therapies in Medicine, 2024. A meta-analysis of 10 trials (772 participants) found better sleep quality scores, with high variation between studies and no improvement in sleep duration. Read the review
Passionflower
Sleep Flow provides 150 mg of passionflower extract per serving.
- Ngan & Conduit, Phytotherapy Research, 2011. A double-blind crossover study in 41 adults who drank passionflower tea for one week. Self-rated sleep quality was better than with placebo. Read the study
- International Clinical Psychopharmacology, 2020. A double-blind, placebo-controlled study using sleep recordings in adults with insomnia disorder over two weeks. Total sleep time increased compared with placebo. Sleep efficiency and time awake did not differ. Read the study
Lemon balm
Research on lemon balm is earlier-stage. Read our summary.
These studies looked at individual ingredients, not Sleep Flow as a complete formula. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.


