Reviewed by Dr. Kathleen Valenton, Board Certified OB/GYN
Published: March 2026 | 5 min read
You Are Not Imagining It: Falling Asleep Really Is Hard
If you have ever lain awake at night, exhausted but unable to fall asleep, you are far from alone. According to the CDC, more than one in three U.S. adults regularly get less than the recommended seven hours of sleep per night.1 And for many people, the problem is not a lack of time in bed. It is the inability to actually fall asleep once they get there.
Difficulty falling asleep is one of the most common sleep complaints, and it often comes down to what is happening in your brain at bedtime. Understanding the basic neuroscience of sleep can help explain why your mind stays wired when your body is ready to rest, and what you can do about it.
What Happens in Your Brain When You Fall Asleep
Sleep is not just your body “shutting off.” It is an active, highly regulated process orchestrated by your brain. Two key systems work together to determine when and how well you sleep.
Your circadian rhythm
Your circadian rhythm is your body’s internal 24-hour clock, regulated by a region of the brain called the suprachiasmatic nucleus (SCN). This clock responds primarily to light exposure, signaling to your brain when it is time to be alert and when it is time to wind down. As evening approaches and light decreases, the SCN triggers the release of melatonin, a hormone produced by the pineal gland that signals to your body that it is time to prepare for sleep.2
Your sleep drive
Separately from your circadian rhythm, your brain also builds up a compound called adenosine throughout the day. The longer you are awake, the more adenosine accumulates, increasing what researchers call “sleep pressure,” the biological urge to sleep. When you finally do fall asleep, your brain clears adenosine, which is why you feel refreshed after a good night of rest.2
When these two systems are aligned, falling asleep feels effortless. When they are disrupted, that is when trouble starts.
Why Your Brain Will Not Let You Sleep
Several common factors can interfere with these natural sleep systems, making it harder to fall and stay asleep.
Stress and an overactive mind
Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, increasing levels of cortisol, the body’s primary stress hormone. Elevated cortisol at night can suppress melatonin production and keep your brain in a state of heightened alertness, making it difficult to transition into sleep even when you are physically tired.3
Screen time and light exposure
Blue light from phones, tablets, and computers suppresses melatonin production by signaling to the SCN that it is still daytime. Research has shown that evening screen use can delay sleep onset and reduce overall sleep quality.2
Irregular sleep schedules
Going to bed and waking up at different times disrupts your circadian rhythm, making it harder for your brain to predict when to initiate the sleep process. Shift work, jet lag, and inconsistent weekend schedules are all common causes of circadian misalignment.2
Caffeine and stimulants
Caffeine blocks adenosine receptors in the brain, directly interfering with your sleep drive. Because caffeine has a half-life of approximately five to six hours, consuming it in the afternoon or evening can significantly delay sleep onset.2
Hormonal changes
For women, hormonal fluctuations throughout the menstrual cycle, during pregnancy, and during perimenopause and menopause can directly affect sleep quality. Declining estrogen and progesterone levels are associated with increased sleep disturbances, including difficulty falling asleep and more frequent nighttime awakenings.4
What the Research Says About Sleep Support
Beyond sleep hygiene habits like limiting screen time, keeping a consistent schedule, and creating a cool, dark sleep environment, several natural compounds have been studied for their potential to support sleep. Here is what the published science says about some of the most researched ingredients.
Melatonin
Melatonin is the most widely studied natural sleep supplement. It is a hormone your brain already produces to regulate your sleep-wake cycle, and supplemental melatonin has been shown in meta-analyses of randomized controlled trials to support a reduction in sleep onset latency (the time it takes to fall asleep), an increase in total sleep time, and an improvement in overall sleep quality.5* Importantly, unlike many prescription sleep medications, melatonin has a favorable safety profile with limited evidence of habituation or tolerance.5
L-Theanine
L-Theanine is an amino acid found naturally in tea that has been shown to support relaxation without causing drowsiness. It works by supporting alpha brain wave activity, which is associated with a state of calm, wakeful relaxation similar to what is observed during meditation.6* By helping calm the mind, L-Theanine may make it easier to transition from wakefulness to sleep.
Magnesium
Magnesium plays a role in sleep through its effects on the nervous system, particularly by supporting the activity of GABA, the brain’s primary inhibitory neurotransmitter. While research on magnesium supplementation for sleep is still evolving, its role in nervous system regulation is well established.
Chamomile
Chamomile is one of the most widely used traditional botanicals to support overall wellness. It has been used for centuries as a botanical of choice.
Glycine
Glycine is a non-essential amino acid that has shown promise for supporting subjective sleep quality. Research suggests that glycine may promote sleep by lowering core body temperature through its action on NMDA receptors in the brain’s suprachiasmatic nucleus, the same region that regulates circadian rhythm.10* In clinical studies, a 3-gram dose of glycine taken before bedtime improved subjective sleep quality, reduced the time to fall asleep, and lessened next-day fatigue and sleepiness in volunteers with sleep difficulties.11*
Valerian root
Valerian root (Valeriana officinalis) is one of the most widely used herbal sleep aids in both the United States and Europe. A 2020 systematic review and meta-analysis of 60 studies concluded that valerian could be a safe herb to promote sleep, though the authors noted that outcomes have been inconsistent across studies, likely due to variability in extract quality and preparation methods.12* Earlier reviews have generally found that valerian may improve subjective sleep quality, but the evidence has not been as consistent when measured with objective tools like polysomnography.12
Lavender and elderberry
Lavender has a long history of traditional use and has been studied for aromatherapeutic properties. Elderberry is a botanical with powerful antioxidant properties. While both are commonly included in sleep-support formulations, they are generally included for their complementary botanical properties and not for their direct influence on sleep.*
Building Better Sleep Habits
No supplement replaces good sleep hygiene. The most effective approach combines consistent habits with targeted support where needed.
Keep a consistent schedule. Go to bed and wake up at the same time every day, even on weekends. This helps reinforce your circadian rhythm.2
Limit screens before bed. Reduce blue light exposure for at least 30 to 60 minutes before your target bedtime to support natural melatonin production.2
Create a cool, dark environment. Your body temperature naturally drops as part of the sleep initiation process. A cool, dark bedroom supports this transition.
Watch caffeine timing. Given caffeine’s approximately five to six hour half-life, consider cutting off caffeine by early afternoon to avoid interfering with your sleep drive.2
Consider targeted supplementation. If you are looking for additional support, look for supplements that combine ingredients researched for different aspects of the sleep process, such as melatonin for sleep onset, L-Theanine for mental calm, and magnesium for nervous system relaxation.5,6,8*
How Lemme Sleep Gummies Support Restful Sleep
Lemme Sleep Gummies are formulated with a combination of ingredients that address multiple aspects of the sleep process, from calming the mind to supporting sleep onset.*
Each serving (2 gummies) contains Melatonin (5 mg), L-Theanine (50 mg), Magnesium as Magnesium Citrate (20 mg), and a Proprietary Herbal Blend (25 mg) that includes Chamomile Extract (Matricaria Chamomilla, flower), Elderberry Extract (Sambucus Nigra, Fruit), and Lavender Extract (Lavandula). Suggested use is 2 gummies 30 minutes before bed.*
Lemme Sleep Gummies are vegetarian, gluten-free, and formulated without synthetic colors.*
FAQ
Why can I not fall asleep even when I am tired?
This often happens when your brain’s arousal systems override your sleep drive. Stress, elevated cortisol, screen time before bed, and an irregular sleep schedule can all keep your brain in an alert state even when your body is physically exhausted. The circadian rhythm and adenosine-based sleep pressure both need to be aligned for sleep to happen smoothly.2,3
Does melatonin actually help you fall asleep?
Yes, meta-analyses of randomized controlled trials have shown that supplemental melatonin can support a reduction in the time it takes to fall asleep, as well as improvements in total sleep time and overall sleep quality.* Melatonin works by reinforcing the signal your brain already uses to initiate sleep. It has a favorable safety profile with limited evidence of habituation.
What does L-Theanine do for sleep?
L-Theanine supports alpha brain wave activity, which is associated with a calm, wakeful state.* Rather than making you drowsy, L-Theanine supports calm the mental chatter that can keep you awake, making it easier to transition into sleep.*
Can hormonal changes affect sleep?
Yes, hormonal fluctuations, particularly in estrogen and progesterone, are closely linked to sleep quality in women. Many women experience sleep disturbances at specific points in the menstrual cycle, during pregnancy, and especially during perimenopause and menopause.4 If sleep difficulties are persistent and seem connected to hormonal changes, consult a healthcare provider for personalized guidance.
When should I see a doctor about sleep problems?
See a healthcare provider if you have persistent difficulty falling or staying asleep that lasts more than a few weeks, if sleep problems are affecting your daytime functioning, or if you suspect an underlying condition like sleep apnea or chronic insomnia. While supplements and sleep hygiene can support healthy sleep, persistent sleep issues may benefit from professional evaluation.
*These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before starting any new supplement regimen.
References
1. Centers for Disease Control and Prevention. FastStats: sleep in adults. Updated May 15, 2024. https://www.cdc.gov/sleep/data-research/facts-stats/adults-sleep-facts-and-stats.html
2. Walker M. Why We Sleep: Unlocking the Power of Sleep and Dreams. Scribner; 2017.
3. Hirotsu C, Tufik S, Andersen ML. Interactions between sleep, stress, and metabolism. Sleep Science. 2015;8(3):143-152. https://pmc.ncbi.nlm.nih.gov/articles/PMC4688585/
4. Baker FC, de Zambotti M, Colrain IM, Bei B. Sleep problems during the menopausal transition. Nature and Science of Sleep. 2018;10:73-95. https://pmc.ncbi.nlm.nih.gov/articles/PMC5810528/
5. Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS ONE. 2013;8(5):e63773. https://pmc.ncbi.nlm.nih.gov/articles/PMC3656905/
6. Hidese S, et al. A randomized, triple-blind, placebo-controlled, crossover study on AlphaWave® L-Theanine. Neurology and Therapy. 2021;10(2):1061-1078. https://pmc.ncbi.nlm.nih.gov/articles/PMC8475422/
7. Lewis ED, et al. Safety and efficacy of AlphaWave® L-Theanine supplementation for 28 days. Neurology and Therapy. 2024;13(4):1077-1096. https://pmc.ncbi.nlm.nih.gov/articles/PMC11263523/
8. Cho S, Yun S. Herbal and natural supplements for improving sleep: a literature review. Psychiatry Investigation. 2024;21(8):810-824. https://www.psychiatryinvestigation.org/journal/view.php?doi=10.30773/pi.2024.0121
9. Hieu TH, et al. Effects of chamomile on sleep: a systematic review and meta-analysis. Complementary Therapies in Medicine. 2024;76:103073. https://pubmed.ncbi.nlm.nih.gov/39106912/
10. Kawai N, et al. Sleep-promoting and hypothermic effects of glycine. Neuropsychopharmacology. 2015;40(6):1405-1416. https://pmc.ncbi.nlm.nih.gov/articles/PMC4397399/
11. Bannai M, et al. Effects of glycine on subjective daytime performance. Frontiers in Neurology. 2012;3:61. https://pmc.ncbi.nlm.nih.gov/articles/PMC3328957/
12. Shinjyo N, et al. Valerian root in treating sleep problems: systematic review and meta-analysis. J Evidence-Based Integrative Medicine. 2020;25:2515690X20967323. https://pmc.ncbi.nlm.nih.gov/articles/PMC7585905/
ABOUT THE EXPERT REVIEWER
Dr. Valenton is a board-certified OB/GYN at Rodeo Drive Women’s Health Center in Beverly Hills, CA, with over a decade of experience in women’s health. She completed her internship and residency at Cedars-Sinai Medical Center, where she remains an attending physician, after earning her Medical Degree from the University of Vermont College of Medicine and dual Bachelor’s and Master’s degrees in Psychology from UC Berkeley. She is also the Chief Medical Officer at Lemme. Her clinical research interests span mental health, hormonal health, infertility, PCOS, and menopause. Dr. Valenton is known for her expertise in pelvic pain, infertility evaluations, and minimally invasive surgery, and remains actively involved in resident education and physician-nursing collaboratives at Cedars-Sinai.
