Skip to content
Free Shipping on all U.S. Orders!
Free Shipping on all U.S. Orders!
Better Sleep: Benefits Of Melatonin And GABA Supplements

Better Sleep: Benefits Of Melatonin And GABA Supplements

We all know sleep is important. It is when the body rests, rejuvenates and repairs. Sleep restores our energy and allows the body and mind to handle whatever the day brings. It feels incredible to easily drift to sleep at the end of the day, only to wake in the morning feeling well rested and alert.

But why is it that something so fundamentally critical for health and wellness is something so many struggle with? Americans are getting less sleep than any other time in history. And nearly 50 percent of us report some kind of issues with sleep.

There are many root causes to sleep issues including stress, technology (TV, phone or computer screens) and the use of stimulants. There may also be underlying medical concerns such as sleep apnea, “adrenal fatigue” known as HPA-axis dysfunction, pain, inflammation or anxiety that contribute to problems sleeping.

For me, my trouble sleeping began in my mid 30’s after I finished my residency in Anesthesiology and began working in private practice. I was “on call” at the hospital for both the main operating room and the Labor and Delivery ward at least every fourth night. Sometimes I worked all day and then all night too. What little sleep I got in the small, uncomfortable “call room bed” was constantly interrupted by my pager going off, a new case, a C-section or an expecting mother needing a new labor epidural. Even when I was able to sleep, the worry of the pager going off kept me from truly getting restful sleep. Poor and inconsistent sleep eventually took a toll. (You can read more about my story and path to functional medicine here.)

You’ve likely noticed connections between your sleep and your health as well. Perhaps during a period of poor sleep you picked up every cold that came your way. Or that one reason you gain weight when stressed is because stress affects your sleep. And any new mom will tell you that sleep deprivation affects her memory, mood and contributes to overwhelm.

Poor sleep patterns are associated with a variety of health issues: higher blood pressure, increased sugar cravings, weight gain, diabetes, heart attacks and strokes. Making it a priority to get enough high quality sleep each night is one of the best things you can do to prevent symptoms and disease down the road.

Even with knowing how important sleep is it can be challenging to actually get the good sleep that you want and need. How do you actually drift off to sleep when you instantly feel alert and stimulated as soon as your head hits the pillow? Or how do you get back to sleep when you wake in the night, with your mind racing?

I’m going to give you some simple, actionable tips to help you upgrade your sleep and support your health. These include tips for implementing good sleep hygiene and natural supplements for better sleep, including melatonin, GABA and glutathione.  

In this article, you will learn more about:

  • Sleep basics
  • The health effects of poor sleep
  • The connection between sleep issues and stress
  • Melatonin, the sleep hormone
  • GABA, the calming neurotransmitter
  • My top 7 tips for better sleep
  • Core Med Science’s combination sleep formula

The Stages Of Sleep

Before we dive into sleep problems, and solutions, it’s helpful to know what normal sleep looks like.

Ideally you need at least 7-8 hours of sleep per night. During this time your body cycles through different stages of sleep. You need 3 or 4 cycles each night that include lighter sleep (stages 1 and 2), REM (rapid eye movement) sleep and deep sleep (stages 3 and 4). You’ll typically naturally wake up at the end of a sleep cycle, but when an alarm (or pager) wakes you up, it is often in the middle of a cycle, leaving you feeling groggy instead of rested.

All of the sleep stages are crucial for maintaining normal body function. REM sleep is important for learning, short term memory and when dreaming occurs. REM sleep also has an important relationship with the neurotransmitter GABA that I discuss below. (Source 1) Stage 3 and 4 deep sleep is the time when your immune system regenerates and you secrete hormones such as sex hormones and growth hormone (Source 2), contributing to a better body composition mood and sex drive.

If you think about all of the ways sleep is disrupted, it is easy to see how this impacts the sleep cycle. Anything from prescription sleep medications, to alcohol and caffeine, to sleep apnea directly disrupts one or several of these stages.­

One way to learn about your sleep patterns is to track your sleep. By gathering more information, you can pinpoint what your sleep issues are and as you work to improve sleep, you’ll be able to see what interventions produce the best results for you. To learn more about the stages of sleep, along with my experience tracking my own sleep, read my article on Sleep Mastery

Poor Sleep Hygiene - Effects of Poor Sleep

In the 2017 National Health Interview Survey, a representative sample of the US population of 26,742 people showed that 49.3 percent of people had sleep problems. The prevalence of the sleep issues was higher in those who are older, female, white and with higher education. (Source 3)

Data from the same survey suggests an increasing trend in short sleep duration, which is defined as 6 hours or less per night, since 2013 and especially among Hispanics and blacks. The study states that inadequate sleep remains a public health concern and that technological, social and economic changes contribute to rising numbers. (Source 4)

Sleep hygiene is defined as a set of behavioral and environmental recommendations or habits intended to promote healthy sleep. The term was originally developed in the context of insomnia treatment. (Source 5) Sleep hygiene habits include your sleep schedule, bedtime activities or routine, your sleeping environment and health habits such as caffeine use. 

Poor sleep hygiene is quite common in our culture and includes staying up late, having inconsistent sleep hours, the use of screens before bed and more. These habits have a big impact. Not enough sleep and poor quality sleep puts stress on the body and raises risk for chronic disease.

Poor sleep…

  • Is a stressor: Sleep deprivation is a chronic stressor on the body, just like dehydration, toxin exposure or even our modern stresses around work, money and relationships. Sleep is important for maintaining homeostasis, or equilibrium, in the body and when impaired contributes to inflammation, decreased brain function and hormone imbalances. (Source 6)
  • Promotes weight gain. In a controlled lab study, 225 healthy participants food intake and timing was observed following 5 nights of sleep restriction. The sleep restricted participants gained more weight than the controls, even over the study’s short period of time. They consumed a staggering 43 percent more calories on the days with the delayed bedtime. (Source 7) It’s no wonder that insufficient sleep is associated with obesity. (Source 8)

You may have noticed that if you have a particularly poor night’s sleep that you don’t have as much energy for healthy behaviors such as cooking or exercise the next day. You are more likely to grab convenience foods and may even experience increased sugar or carb cravings throughout the day. It’s your body’s way of trying to get some quick energy, but it isn’t a substitute for good sleep.

  • Increases insulin and blood glucose. Chronic sleep issues lead to an increase in blood glucose (blood sugar), which leads to insulin resistance, metabolic syndrome and type 2 diabetes. (Source 8) These changes in hormones are another reason that poor sleep contributes to obesity.
  • Affects the brain. Sleep deprivation negatively affects mood, cognitive performance and motor function. (Source 9) Loss of sleep affects plasticity in the brain, which affects brain function in terms of alertness, cognition and mood. Much of the research that looks at how sleep affects the structure of the brain has been done on animals. (Source 10)

In a 2017 study of nurses who work the night shift, fatigue, increased family stress and mood changes were reported. The symptoms and consequences of working the night shift were especially hard for those who rotated shifts and therefore had to switch sleep-wake cycles throughout the week. (Source 11)

  • Increases mortality. In addition, sleep duration is linked with mortality. In this meta-analysis, both short sleep times (less than 7 hours per night) and long sleep times (over 9 hours per night) were associated with an increased rate of all-cause mortality. The study suggests the sweet spot for sleep supporting health between 7 and 9 hours per night. (Source 12)

Poor Sleep And Stress

There are many factors that contribute to poor sleep and to get to the bottom of compromised sleep you’ll need to uncover your unique root causes. When we can address the root through natural methods we support health and healing. This is the way we don’t apply Band-Aid treatments to sleep using addictive sleep aids or medications. Those don’t actually provide the type of restorative sleep your body requires for healing and repair, they just sedate your system.

One of the biggest influencers on sleep that I see in my patients and community is stress.

Stress can make it hard to fall asleep and stay asleep, especially when feeling anxious or the mind is racing. In the functional medicine space you’ll often hear the term adrenal fatigue, or more correctly HPA-axis dysfunction. This refers to an imbalance in brain and adrenal hormones that contribute to the body’s stress response.

Cortisol, a main stress hormone, has a daily rhythm and is ideally high in the morning and low at night. This pattern helps you to feel alert during the day and tired at night. When the pattern is off, it affects sleep. Reasons for cortisol levels to be off include blood sugar or insulin issues, inflammation, gut infections, sex hormone imbalances, stress (both psychological and environmental), hidden infections and general lifestyle habits like alcohol, sugar and caffeine.

For example, high cortisol at night can make it hard to fall asleep and you may feel wired, even though your body is tired. This can cause significant sleep anxiety. To compound the problem, poor sleep contributes to increased evening cortisol levels. (Source 6)

Adrenal fatigue symptoms include:

  • Not feeling rested, even after a full night’s sleep
  • Afternoon or all-the-time fatigue
  • Sugar and salt cravings
  • Low blood pressure
  • Dizziness with standing
  • Imbalances in thyroid or sex hormones
  • Dependence upon caffeine to “get going”

Restoring quality sleep is an important adrenal fatigue treatment and key factor in restoring health and preventing disease.

Before I get into the specifics of how to restore sleep, I want you share the research on two important sleep compounds: melatonin and GABA.

Melatonin – Your Sleep Hormone

Melatonin is a hormone made by your brain, in the pineal gland, that helps to regulate your circadian rhythm and fall asleep at night. It has an opposite rhythm from cortisol, where it is low in the morning and increases at night. Its secretion is stimulated by darkness and suppressed by light.

Melatonin can be taken as a supplement for sleep and there is strong scientific evidence for its use in insomnia.

In a double blind study of those with insomnia, melatonin supplementation was effective for reducing sleep latency (the time it takes to fall asleep) and improving sleep quality. This translated to better alertness in the day, without side effects. (Source 13) Another randomized controlled trial showed time release melatonin effective in substantially improving insomnia symptoms in 50% of the trial group compared to only 15% in the control group. The melatonin did not impair motor skills the next day. (Source 14)

Delayed sleep phase syndrome (DSPS) is a chronic dysregulation of the circadian rhythm that causes you to fall asleep at least two hours later than a normal sleep pattern that correlates with day and night. Several studies show melatonin as a helpful therapy for this condition, improving sleep latency and feeling refreshed the next day. (Source 15, 16) In addition, melatonin improves depression that often corresponds with DSPS. (Source 16)

Melatonin supplementation is also used in blind people to establish circadian rhythm in the absence of light and dark cues. (Source 17)

If you are considering a melatonin supplement for sleep, typical dosages range from 500 mcg to  5mg. More isn’t always better, and in the case of melatonin, a lower dose may be more effective for some.

GABA Supplement Benefits, Neurotransmitters and Anxiety

In addition to the hormone melatonin, GABA is another important sleep molecule. GABA, or gamma-aminobutyric acid, is the main inhibitory neurotransmitter in the body. It counteracts the excitatory neurotransmitters, including glutamate, to reduce the activity of neurons, which makes GABA calming, relaxing and helps promote sleep. It’s incredibly important for the parasympathetic response, which is the opposite of the nervous system stress response also known as the sympathetic response or “fight or flight.” This effect is why GABA supplementation promotes relaxation and decreases anxiety. (Source 18)

When it comes to sleep, GABA levels are important. Research suggests that those with insomnia may have less GABA production than those with normal sleep. (Source 19) Popular sleep supplements including valerian, hops, magnesium, l-theanine, kava, passionflower and others, all affect GABA activity in the brain to produce the calming effect that leads to sleep.

The primary function of GABA supplements is sleep. Studies show that GABA supplementation safely helps people to fall asleep more quickly, in one study by 5.3 minutes. (Source 20) GABA promotes sleep by activating the GABAA receptors in the nervous system. In another study, GABA combined with l-theanine, increased sleep latency by 15%, sleep duration by 26% and improved non REM sleep (deep sleep) by 20%. (Source 21)

A controversy surrounding the effectiveness of GABA supplementation is that GABA is a large molecule thought to not cross the blood brain barrier, and therefore not be able to enter the brain. The studies assessing this claim have varied widely in their methodology and have contradictory results. (Source 22)

However, many people have immediate and profound effects from GABA supplementation that may be attributed more than placebo. Even if GABA is poor at entering the brain, there are GABA receptors in the gut (Source 23) and therefore may affect the brain via the gut-brain axis. (Source 24) In addition, many experience sleep anxiety, the anxious feeling that arises when thinking about sleep, and more specifically not being able to fall asleep. If you find yourself checking the clock with a racing mind, a GABA supplement for sleep might help.

An effective GABA dosage for sleep is in the range of 100-200mg. However, you may need less if you take your supplements in a liposomal form.

Dr. Popa’s 7 Tips For Better Sleep

You’ve made it this far in the article, and now you are likely interested in improving your sleep and you are ready for some action steps! Here are my suggestions for improving sleep hygiene and building simple, yet very helpful, daily habits that promote easier and more restful sleep.

  1. Get on a regular schedule. This means setting a bedtime – and sticking to it. By going to bed at the same time each night and waking at the same time each morning, you help to set your body’s internal clock. Your body will begin to want sleep when bedtime approaches. Most people do well with 7 to 9 hours of sleep each night. To find your sweet spot, see what time you naturally wake (without an alarm) and count backwards to establish your bedtime. Most people catch their deepest sleep between 10PM – 12 AM so it might be helpful to get into bed early and ensure you are asleep by 10PM.
  1. Regulate light. Remember how darkness triggers melatonin and light suppresses it? In our modern environment we are frequently exposed to light after dark from indoor lighting and screens. Try using lamps in the evening instead of overhead lights and limiting screen time in the hour or so before bed. If you are on a phone, laptop or watching TV after dark, try wearing blue light blocking glasses.

In addition, light exposure during the day is important. Open shades when you wake up and get outside for a morning walk. If you don’t have much natural light in your daytime environment make a point to take breaks and get outside.

  1. Upgrade your sleep environment. Your bedroom should be cool and dark. Perhaps you’ll need blackout curtains or a sleep mask to block out outdoor light. Adjust the thermostat so that you aren’t too hot, around 60-68 degrees is preferable. In addition, make sure your bed and bedroom are comfortable and inviting. Replacing old pillows and mattresses may be a fast solution for better sleep. Work, watch TV and do other activities in other areas of your home and save your bedroom for sleep (and sex) only.
  1. Create a bedtime routine. Use the time before bed to do relaxing activities. Shut off the news, social media or anything else that might be stimulating or stressful. Instead, wind down with a hot bath, herbal tea such as chamomile, some stretching or yoga, meditation, writing in a journal, reading for pleasure or other relaxing activities that you enjoy. Close to 30% of people with sleep issues utilize and receive benefit from mind body approaches. (Source 3)
  1. Reduce caffeine and alcohol. Both can interrupt sleep. If you are really attached to your daily coffee or glass of wine, try an experiment to understand how it affects you. Compare your sleep quality on the nights you drink alcohol versus the nights you don’t. See if limiting caffeine to only before noon helps with sleep. If you are particularly sensitive, you might need to limit caffeine to one cup in the morning or switch to a lower caffeine alternative.
  1. Exercise during the day. Perhaps you’ve noticed with kids that if they are particularly active in a day, they “tire themselves out” and sleep better at night. The same is true for you. In a randomized controlled trial, even minimum levels of recommended activity per week helped to improve insomnia. The minimum recommendation is at least 150 minutes of moderate to vigorous activity per week. (Source 25)

Yoga might be particularly beneficial. When compared to walking, yoga was shown to increase GABA levels, improve mood and decrease anxiety. (Source 26)

  1. Utilize sleep supplements. It can take time to adjust your routine, experiment and build lasting habits. As you put the lifestyle pieces in place for sleep, supplements help to bridge the gap. After all, you’ll have more energy to shop for blackout curtains or exercise when you are well rested.

Melatonin and GABA Supplements for Better Sleep

By now you know that both melatonin and GABA supplements are powerful sleep support and help to improve the quality, duration and time it takes to fall asleep. That’s why I created Core Med Science Liposomal Sleep Formula. This formula combines melatonin and GABA along with glutathione, all delivered in liposomal form for superior absorption.

Glutathione is known as the body’s “master antioxidant” because along with its own antioxidant powers, it also helps the body to increase and recycle other antioxidant molecules. Glutathione benefits are many. It supports detoxification, much of which happens at night, making it the perfect addition to this sleep formula. I’ve also found that one reason that many people have trouble sleeping is because of inflammation and pain, which glutathione helps to reduce. (Note: if you are experiencing pain and inflammation, you might enjoy my recent article on liposomal curcumin, which covers these topics in greater detail.)

Core Med Science Liposomal Sleep Formula is best taken 30 minutes before bedtime and comes in a convenient pump so you can easily titrate up your dose (up to 6 pumps) for best results. Of course, please check with your personal provider to discuss if this supplement is right for you, especially if you take medication, have a medical condition or are pregnant or nursing.

Summary Of The Key Points You Learned Today:

  • Normal sleep includes 3 to 4 nightly cycles through light sleep, deep sleep and REM sleep.
  • Sleep problems affect almost half of the adult population.
  • Poor quality and not enough sleep contribute to chronic disease.
  • Poor sleep is a stressor on the body, promotes weight gain, increases blood sugar, affects cognition and mood and is related to all-cause mortality.
  • Stress greatly contributes to poor sleep and HPA-axis dysfunction.
  • Melatonin, the body’s sleep hormone, is used as a supplement to improve sleep, with the strongest evidence for insomnia and delayed sleep phase syndrome.
  • GABA, the body’s calming neurotransmitter, is used as a supplement to improve sleep and reduce anxiety.
  • Sleep hygiene practices help to improve sleep and these include: maintaining a regular sleep-wake schedule, mimicking outdoor light (and dark) indoors, creating a bedroom environment conducive to sleep, creating a bedtime routine, reducing stimulants that disrupt sleep and utilizing supplements.
  • Core Med Science’s Liposomal Sleep Formula delivers melatonin, GABA and glutathione in a liquid liposomal form for superior absorption.

I know first-hand how important sleep is. Along with good nutrition, exercise and my supplement routine, sleep is essential for bringing my A game to my work as an anesthesiologist. A good night’s sleep allows me to do all of the things that I am most passionate about, including learning more about biochemistry and the best way to deliver nutrients to the cells that need them most. And when life becomes a little more stressful and hectic, I’m not afraid to lean on natural supplements that are safe and effective without the side effect of pharmaceutical sleep medications.

My hope is that this information brings you some ideas, strategies and ultimately, more restful sleep. Here’s to a good night’s sleep!

References

  1. Fraigne, J. J., Torontali, Z. A., Snow, M. B., & Peever, J. H. (2015). REM Sleep at its Core - Circuits, Neurotransmitters, and Pathophysiology. Frontiers in neurology, 6, 123. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4448509/
  2. Takahashi, Y., Kipnis, D. M., & Daughaday, W. H. (1968). Growth hormone secretion during sleep. The Journal of clinical investigation, 47(9), 2079–2090. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC297368/
  3. Voiß, P., Höxtermann, M. D., Dobos, G., & Cramer, H. (2019). The use of mind-body medicine among US individuals with sleep problems: analysis of the 2017 National Health Interview Survey data. Sleep medicine, 56, 151–156. Abstract: https://pubmed.ncbi.nlm.nih.gov/30799256/
  4. Sheehan, C. M., Frochen, S. E., Walsemann, K. M., & Ailshire, J. A. (2019). Are U.S. adults reporting less sleep?: Findings from sleep duration trends in the National Health Interview Survey, 2004-2017. Sleep, 42(2), zsy221. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6941709/
  5. Irish, L. A., Kline, C. E., Gunn, H. E., Buysse, D. J., & Hall, M. H. (2015). The role of sleep hygiene in promoting public health: A review of empirical evidence. Sleep medicine reviews, 22, 23–36. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4400203/
  6. McEwen B. S. (2006). Sleep deprivation as a neurobiologic and physiologic stressor: Allostasis and allostatic load. Metabolism: clinical and experimental, 55(10 Suppl 2), S20–S23. Abstract: https://pubmed.ncbi.nlm.nih.gov/16979422/?dopt=AbstractPlus
  7. Spaeth, A. M., Dinges, D. F., & Goel, N. (2013). Effects of Experimental Sleep Restriction on Weight Gain, Caloric Intake, and Meal Timing in Healthy Adults. Sleep, 36(7), 981–990. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3669080/
  8. Reutrakul, S., & Van Cauter, E. (2018). Sleep influences on obesity, insulin resistance, and risk of type 2 diabetes. Metabolism: clinical and experimental, 84, 56–66.https://pubmed.ncbi.nlm.nih.gov/29510179/
  1. Durmer, J. S., & Dinges, D. F. (2005). Neurocognitive consequences of sleep deprivation. Seminars in neurology, 25(1), 117–129. https://pubmed.ncbi.nlm.nih.gov/15798944/
  2. Raven, F., Van der Zee, E. A., Meerlo, P., & Havekes, R. (2018). The role of sleep in regulating structural plasticity and synaptic strength: Implications for memory and cognitive function. Sleep medicine reviews, 39, 3–11. Abstract: https://pubmed.ncbi.nlm.nih.gov/28641933/
  3. Books, C., Coody, L. C., Kauffman, R., & Abraham, S. (2017). Night Shift Work and Its Health Effects on Nurses. The health care manager, 36(4), 347–353. Abstract: https://pubmed.ncbi.nlm.nih.gov/28953576/
  4. Gallicchio, L., & Kalesan, B. (2009). Sleep duration and mortality: a systematic review and meta-analysis. Journal of sleep research, 18(2), 148–158. Full text: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2869.2008.00732.x
  5. Lemoine, P., Nir, T., Laudon, M., & Zisapel, N. (2007). Prolonged-release melatonin improves sleep quality and morning alertness in insomnia patients aged 55 years and older and has no withdrawal effects. Journal of sleep research, 16(4), 372–380. Full text: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2869.2007.00613.x
  6. Luthringer, R., Muzet, M., Zisapel, N., & Staner, L. (2009). The effect of prolonged-release melatonin on sleep measures and psychomotor performance in elderly patients with insomnia. International clinical psychopharmacology, 24(5), 239–249. Abstract: https://pubmed.ncbi.nlm.nih.gov/19584739/
  7. Nagtegaal, J. E., Kerkhof, G. A., Smits, M. G., Swart, A. C., & Van Der Meer, Y. G. (1998). Delayed sleep phase syndrome: A placebo-controlled cross-over study on the effects of melatonin administered five hours before the individual dim light melatonin onset. Journal of sleep research, 7(2), 135–143. Full text: https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-2869.1998.00102.x?sid=nlm%3Apubmed
  8. Rahman, S. A., Kayumov, L., & Shapiro, C. M. (2010). Antidepressant action of melatonin in the treatment of Delayed Sleep Phase Syndrome. Sleep medicine, 11(2), 131–136. Abstract: https://pubmed.ncbi.nlm.nih.gov/20044310/
  9. Fischer, S., Smolnik, R., Herms, M., Born, J., & Fehm, H. L. (2003). Melatonin acutely improves the neuroendocrine architecture of sleep in blind individuals. The Journal of clinical endocrinology and metabolism, 88(11), 5315–5320. Abstract: https://pubmed.ncbi.nlm.nih.gov/14602767/
  10. Abdou, A. M., Higashiguchi, S., Horie, K., Kim, M., Hatta, H., & Yokogoshi, H. (2006). Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humans. BioFactors (Oxford, England), 26(3), 201–208. Abstract: https://pubmed.ncbi.nlm.nih.gov/16971751/
  11. Winkelman, J. W., Buxton, O. M., Jensen, J. E., Benson, K. L., O'Connor, S. P., Wang, W., & Renshaw, P. F. (2008). Reduced brain GABA in primary insomnia: preliminary data from 4T proton magnetic resonance spectroscopy (1H-MRS). Sleep, 31(11), 1499–1506. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2579978/
  12. Yamatsu, A., Yamashita, Y., Maru, I., Yang, J., Tatsuzaki, J., & Kim, M. (2015). The Improvement of Sleep by Oral Intake of GABA and Apocynum venetum Leaf Extract. Journal of nutritional science and vitaminology, 61(2), 182–187. Full text: https://www.jstage.jst.go.jp/article/jnsv/61/2/61_182/_article
  13. Kim, S., Jo, K., Hong, K. B., Han, S. H., & Suh, H. J. (2019). GABA and l-theanine mixture decreases sleep latency and improves NREM sleep. Pharmaceutical biology, 57(1), 65–73. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6366437/
  14. Boonstra, E., de Kleijn, R., Colzato, L. S., Alkemade, A., Forstmann, B. U., & Nieuwenhuis, S. (2015). Neurotransmitters as food supplements: the effects of GABA on brain and behavior. Frontiers in psychology, 6, 1520. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4594160/
  15. Auteri, M., Zizzo, M. G., & Serio, R. (2015). GABA and GABA receptors in the gastrointestinal tract: from motility to inflammation. Pharmacological research, 93, 11–21. Abstract: https://pubmed.ncbi.nlm.nih.gov/25526825/
  16. Baj, A., Moro, E., Bistoletti, M., Orlandi, V., Crema, F., & Giaroni, C. (2019). Glutamatergic Signaling Along The Microbiota-Gut-Brain Axis. International journal of molecular sciences, 20(6), 1482. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471396/
  17. Hartescu, I., Morgan, K., & Stevinson, C. D. (2015). Increased physical activity improves sleep and mood outcomes in inactive people with insomnia: a randomized controlled trial. Journal of sleep research, 24(5), 526–534. Full text: https://onlinelibrary.wiley.com/doi/full/10.1111/jsr.12297
  18. Streeter, C. C., Whitfield, T. H., Owen, L., Rein, T., Karri, S. K., Yakhkind, A., Perlmutter, R., Prescot, A., Renshaw, P. F., Ciraulo, D. A., & Jensen, J. E. (2010). Effects of yoga versus walking on mood, anxiety, and brain GABA levels: a randomized controlled MRS study. Journal of alternative and complementary medicine (New York, N.Y.), 16(11), 1145–1152. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3111147/
Previous article How to Heal Gut Microbiome Activity with Berberine